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Unit 10A, Block 1, Dockyard Industrial Estate, Woolwich Church Streeet
London SE18 5PQ
United Kingdom


We create circuits that are both beautiful and functional


Making a Boldport Club project

Ben Barwise

As we prepare to ship the last ‘monthly’ Club project (see announcement), I thought that it would be interesting to write about the first board I designed at Boldport. As it happens it’s also the most interesting of my projects to talk about too. Ananas is made of a simple circuit that’s repeated and built into a complex three dimensional two-PCB construction. It is a bit of a puzzle, involving some craft but rewards the builder at the end with some slow fading ‘blinky’ lights and, of course, it looks like a pineapple!

Why start easy? the board

Marking the sides of the maquette to check power connections could be joined

This PCB design was possible because of Boldport’s unique software called PCBmodE. The organic-like shapes you see on the board are directly worked on as part of the board layout rather than an after-the-fact separate graphic import (as is done with other circuit design tools). All components, shapes, and traces are drawn in SVG format using Inkscape, organized using JSON files and then compiled into Gerber format for manufacture. PCBmodE, however, is missing the ‘luxuries’ of DRC and schematic capture but there is far fewer restrictions on the shapes and traces. It is almost like a virtual equivalent to freehand PCB layout, like in the ‘old days’.

Detail of the shapes of the PCB, especially the pads which are all different shapes to denote where components can be placed.

It is hard to imagine what it is like to layout in PCBmodE unless I give an example. The pads on Ananas are not all round or square: some are diamond, hexagon, and even star shaped. This is because every part of the board is accessible as an SVG shape. With other software tools you have to stick with the simple built-in pad shapes like ellipse and rectangle because that is where the software’s pad feature stops. But in PCBmodE by default everything is an editable SVG.

You would think that starting out with new a new design tool I should try something simple and flat, but instead I challenged myself and went with 3D! By fixing together two round and slotted boards at 90 degrees I found that I could create a form that hinted at being a sphere.

I had a circuit in mind for the board but first wanted to test the idea by making a simple cardboard maquette. This is essential when designing a board, any board, as it is impossible to have a good feel for size when you only experience it on a screen. I worked out that if the board’s power connections were polarized in a certain way, I could make solder connections that would not only fix the boards together but also carry the power. This way, the two boards will be identical, making it more economical to manufacture.

Iterating through designs. (left to right) original size prototype, after shrinking down, with layout applied.

Making a model is important as it is very hard to mentally keep track of where the sides meet. Here, there are four surfaces to think of and I don’t think that I could have worked this out otherwise. This exercise also helped me realize that because of its shape I could fashion a simple battery holder that could be part of the PCB’s shape. I rather optimistically made the first version quite large but then had to shrink it down for cost reasons. I now think, however, that the compact version ended up looking better.

I tried out various conventional ways of marking component placement but found them to be too messy. My solution was to make the pads have different shapes (as discussed above). This also added to a puzzle-like quality to the project experience.

Next came the physical prototype PCBs and sourcing components. If you see below I actually made two prototype PCBs as my first had a few errors in it (always triple check your designs!). Because of the large component quantity per kit, it made it easier for me to get bulk prices on the components, which meant that we had budget for other project enhancements. On the middle design in the picture below you can see I also played with the idea of peeling the capacitors.

Left to right: First prototype, second prototype, finished product

Make it easy! the circuit

When designing a project it’s very tempting to make it have as many exciting features as possible (otherwise known as ‘feature creep’). With this project, I wanted to keep it quite simple and clean as the components were also a decorative element of the design.

I wanted this to be some kind of ‘blinky’ decoration so after going through a few ideas I decided to use a simple discrete circuit with NPN transistors and avoid ICs all together. Using discrete components allowed me to spread out the layout. By using ICs, traces typically all converge back to the IC which would be a real challenge to route for a circuit based on four planes.

The circuit is a type of transistor ring oscillator for which there are a number of variations. The way it works is number of sections oscillate from high to low in a circle. The frequency of the movement depends on the resistor and capacitor values. Due to the power restrictions of a 2030 battery I wanted to keep the number of sections active (drawing power) at the same time to a minimum. I concluded that stringing three sections in a row works best as only one LED is on at the same time. Then putting that circuit on each quarter of the shape (so four circuits altogether) would mean that it should draw a fairly low amount of current and all that needs to pass between the sides is power. I chose yellow LEDs because of all LEDs they have the lowest forward voltage drop (Vf), this was a useful property because there was not much voltage for the LEDs running off a 3v coin. I also like the colour yellow!

As there was no silkscreen reference designators — the yellow part of the PCB is the silkscreen layer — it is good to include a reference guide that you can use along side assembly. I provided that guide on a small green piece of card that also nicely doubled as the paper to create leaves on top of the assembled Ananas. Further help and instruction could be found on the Ananas page, as is common with other Club projects. In addition, I even did a detailed build video so if anyone gets stuck at any point could get some clues.

Packaging it up

Once designed you have to think about getting it to the end user! Boldport projects all come with thoughtful and interesting packaging, and this one was no exception. I thought it would be great to make the shipping package bright and colourful like someone is getting a surprise through the door. After a bit of searching I found these bright bubble mailers that reflect the cell-like pattern of the PCB. I realised it would be great to have a sort of logo for the kit to stick on the front again making it stick out when it comes through the door!

Ahhh they are all opening themselves!

Ahhh they are all opening themselves!

A last minute minor crisis that came up was that the adhesive on the envelopes sometimes failed after a day or so — some started opening all by themselves. We solved this by sticking the postage label over the flaps. This example is just one of many where one needs to test everything, even if it “should just work”. If we had not had a break between putting the components in the envelopes and shipping, some packages could have opened in transit!

Final Thoughts

The Importance of prototypes

Lite 2 Sound BC - It took making a board to realize the dimensions were off and the battery does not fit.

Every project I produced for Boldport club required many mock-up tests with cardboard maquettes and with the PCB prototypes. For example, with the project Lite2Sound BC I had to make the board and the battery fit into the tin enclosure. I thought I had it with the cardboard test with which I had even glued the battery contacts into the cardboard. But when the PCB prototype came both the contacts were too high and the board too large. Prototype often!

Another example is Krell, which I designed to fit in the palm of a hand. In this case the cardboard was not going to do, so I made a version out of a prototype board.

Krell - As it was hand held it took a lot of physical testing to get a feel for the board

I like stickers!

Something I could not stop producing for each kit was stickers, and below is a selection of them. With the Lite2Sound BC kit for example the sticker was actually used to block light out of an enclosure opening.

Actual final thoughts

It has been a great opportunity to design these kits with Saar’s direction and advice. I’ve learnt a lot about sourcing and producing designs on a rolling monthly schedule. One interesting takeaway is it is amazing what one little task can do to the production speed of 500+ projects. For example, wrapping PCBs in tissue paper can take a long time. At the end it’s a balance between the amount of work versus the effect each step has on the final result and user experience.

I have enjoyed working in the Boldport studio and there is so much encouraging enthusiasm from the Club members. Highlights have been watching members live-stream their builds and I always enjoy a satisfying shipping day! The work has always been interesting and challenging and I am looking forward to see what Saar creates for Boldport in the future, especially now some limits have been lifted. There will be many exiting new things to come!

Boldport Club is changing

Saar Drimer

Quick, quick, what’s happening?!

We’ll be shipping our last monthly project in January 2019. Then, we’ll continue to design unique projects on an ad-hoc basis that will be available at an open-to-all shop. From January new members will join the Club through purchasing items from the shop. Our community will continue to flourish on Discord where all current and past members are welcome to join.

OK. I’m sitting down now. Please tell me more!

At the Boldport Club we ship unique soldering projects and PCB art to members. I’ve set the rules when I started: unique and exciting project sent each month at fixed monthly cost that includes shipping to anywhere in the world. Over nearly three years we've had almost 1000 paying members and for the past year 500 active members. By January ‘19 we will have shipped 32 creative projects and over 15,000 packages to members in over 30 different countries.

Boldport Club has been a success on most measures. Through this service I've accomplished what I set out to do: combine art, product design, and electronics sold to those who appreciated the combination. All our projects are open source hardware, designed using our own open source software, PCBmodE. The subscription model allowed me to be more creative and experimental than I would with an ‘ordinary’ online shop. Having the freedom to create, knowing more-or-less how many instances to make a few months in advance, really helped with logistics, finances, and the mind. I’ve met my ambition to deliver on time ─ only one project was late ─ at a time where many ‘speculative’ hardware projects fail to (crowdfunding, etc.) It’s an achievement I’m proud of. It wasn’t my goal to satisfy everyone all of the time and with every project. I tried, though, to make sure that something hit everyone’s preference sweetspot ─ aesthetics, build challenge, functionality, etc. ─ within a few projects. I did my best to provide a unique experience and good value-for-money to those with little, or a lot of, experience with electronics and soldering. Trying and failing to build a project was part of the experience, and we supported it. Ultimately, I strived to create experiences through electronics.

To my delight many supported this model and vision, paying in advance to get the Club's projects without knowing what they would be. 170 of you signed up before I shipped the first project in March 2016! This is incredible and humbling to me, but also a strong vote of confidence in my ability to deliver and innovate high quality projects on a tight budget and time constraints.

People overwhelmingly love the Club, the projects, our community, and what we are about. We did the surveys. We read the feedback and see the numbers. Our community on Discord ─ we moved from Slack last week! ─ is incredibly insightful, helpful, and respectful, and a key benefit of the Club for many. From past experience I know that creating such a community is hard, but together with you we've done it! I'm so satisfied with that.

With every project I tried to introduce something new that I hadn’t seen before or that I wanted to try out. Initially, for coming up with interesting projects I relied on past concepts, ideas, and experiences that I collected throughout my career. Naturally, this became increasingly more challenging with time. I recently realised that I'm essentially competing with myself, while others are catching up (it has been great seeing #BadgeLife become a thing, for example). Constantly ‘levelling-up’ is hard while the budget and time constraints remain the same. I found that for every project that we end up sending to members we go through evermore fleshed out project candidates that I then decide are not good enough. It’s consuming.

We’ve no lack of creative juices and energy for doing more in the space that Boldport is a recognised name in. We have loads of promising concepts and project ideas that we aren’t able to realise as ‘Club projects’ in the current format. My decision to stop the monthly shipments, perhaps only temporarily, will give us time and mental space to investigate those further.

Some things didn’t quite work out, obviously. Initial growth was fast and when I established the current price of a subscription ─ £19 per month ─ in early 2017 the membership growth curve was steep and I assumed a break-even at 500 members. That growth didn’t continue. (This also meant I still have a large amount of stock I created in anticipation of this growth.) Having about 500 active members for a year now, it’s an amount that’s more than 'not worth the while' but also 'too frustratingly close to breaking-even'. I could not currently see a way to get to 1000 or 2000 members with our available resources ─ if that market exists at all is an open question ─ and I certainly do not want to compromise our high standards. I’ll also happily admit that I’m not good at marketing and promotion. All this contributed to my decision for a change.

Another contribution to my decision for change is the uncertainty of the unnecessary and misguided national self-harm called Brexit. The confusion, logistics overhead, and higher costs that have already been a burden for over two years and that will continue are affecting my outlook, of course. Commercially, small voiceless businesses such as Boldport will suffer a great deal. Being more nimble during this period ─ that is, having fewer commitments to customers and suppliers ─ will allow Boldport to ride the transition and then evaluate if, when, and where I’d like to continue the work once the dust settles.

Many thanks for all of you who are and were members of the Club and are part of our wonderful community. Some of you stuck with it since the very beginning, which is incredible. You are part of something special. Special thanks to Mr Barwise who joined me at Boldport September of last year and who initiated and/or designed the PCBs, packaging, and associated materials for wonderful, creative, and loved Club projects (Ananas, The Conehead, Whiteboard, Lite2Sound-BC, and Krell). We’ve had the privilege to collaborate with talented and kind people who allowed us to remix their work as Club projects: Lucky Resistor (PissOff), James Hutchby of Madlab (Stringy and Krell), Eric Archer of RareWaves (Lite2Sound-BC), and Jez Siddons of Peak Electronic Design (Capaci-meter). Our projects have also been supported to various degrees by the good folk of Eurocircuits, Snaptron, AMS, and Microchip. Our support contacts at Farnell and Toby have been very helpful in getting us the best possible component prices. Finally and especially, remarkable Club members contributed their time and talent without any reward to help the Club grow and glow. My gratitude is yours.

To stay up to date, join the Boldport Club mailing list or follow us on Twitter.

So what will happen after January?

We’ll be working on exciting new projects that will be larger, smaller, and different than Club projects so far. We’ll be exploring new concepts, but also revisiting past successful projects that can benefit the new format (we’re currently thinking of a more elaborate 3X7 and The Matrix, for example.) We’re likely to make projects in limited quantity, and we’ll announce them to the community first.

The Club shop will become open to all. Joining the Club community will be easier, requiring a shop purchase of a certain TBD amount. Existing stock of Club projects will be available at the Club shop, although at noticeably higher cost than they are now available to members.

If you’d like to support our future work, please do so by spreading the word, and by purchasing items from the shop ─ they’d make great gifts.

What about the existing subscriptions?

We have three monthly projects to send you and they are great: Respot (November), Capaci-meter (December), and Pease-out (January). If you’re an active member we’ll be adjusting your subscription so that you continue to pay the same amount per project of your current subscription, but won’t be charged for projects beyond January. (For example if you’re on a 12-month cycle paying £17 per project you’ll continue paying that amount, just billed once a month.)

If you’ve already paid for projects after January you’ll be able to choose to either get a refund, or ─ this option is far better for us! ;) ─ up to twice what we’d owe you as shop credit. We’ll be in touch about this.

Solder on,

Boldport Club at 500

Saar Drimer

Boldport Club now has over 500 active members! That's 500 people the world over receiving the soldering projects that we design and manufacture every month in London. It's certainly reason to celebrate and reflect. We've compiled some stats to evaluate what's been going on for the past two years and to understand the make-up of our wonderful community. We've gathered data from our subscriber and shipping records and from a questionnaire that was completed by nearly 200 people.

Looking back

Growth curve of Boldport Club membership, composed of joined and cancelled memberships. Each data point is an accumulation over about 15 days.

We shipped Pease, our first project, mid-March 2016. By then we already had an astonishing 170 members who were confident enough that we will deliver interesting projects. We've had strong growth in 2016 and gained a net of 100 members in 2017.

We strive to create a diverse community. We'd like to have people from different personal and professional backgrounds, varied levels of experience with electronics, and different life experiences. This is how we can learn from and inspire each other. This diversity creates a healthy environment for making the Club fun, creative, and stimulating. In our questionnaire we learned a bit more about our members backgrounds. 


Most of our members are from technology-related industries, but we have members from many other sectors. Based on questionnaire responses.

Based on questionnaire responses

We learned from the questionnaire that most of our community is from the technology industry (software, engineering, IT, etc.) It's great to see that we are also able to attract members from other fields such as healthcare, law, and transport. Most of our members 'dabble' with electronics or do it professionally. About 10% of members are women and we would very much like to improve on that.

On our Slack — where the majority of community interaction happens with about 75K messages so far — it's remarkable that there's an expert in almost any topic discussed. We discuss everything from individual projects to cooking, 3D printing, and PCB design. For every question, however trivial or complex, there are a few people that almost immediately help out. This community works! Members also contribute to a member-managed contribution site with project resources.

In the coming year we'll continue working towards making the community even more engaging, stronger, and more welcoming to everyone.

Members by country. We show only countries with active+cancelled >= 10. Based on our records.

We have members from all over the world; most are from the US. In the US, California is where most members are. In total we've shipped 22 projects in about 8300 packages. Only one project was delivered late; that is, shipped after our self-imposed deadline of the 15th of the month.

In our questionnaire we asked people about their expectations when they've joined the Club and whether those expectations were met after experiencing being part of the Club. Most people regard the Club to be good value for money.

People seem to be satisfied, which is great for us to hear. Another strong indication for this is that the average length of subscription is well over a year! (We've only been shipping for two years.)

Based on questionnaire responses

Based on questionnaire responses

Based on questionnaire responses

When we asked what attracted members to the Club, the answers were about what we expect: all the things we created the Club for and what we enjoy working on. Also, this is what puts the Club apart from other electronics project creators.

A multiple-answer question from the questionnaire

Members can buy previous projects from the Club shop. The figure below shows what people ordered over the past couple of years. It's interesting to identify popular projects like The Matrix and The Monarch. Less popular projects are SPOOLT and IxpandO. Pease was very popular but was sold out right after we shipped it to members. We constantly study what works and what doesn't, but without compromising of our vision and what we aim to deliver.

Amount of projects ordered from the shop from our shipping records. This graph isn't normalised to how long the project was available and whether it is sold out. For example, 'Pease' was sold out right after we shipped it to members.

In July of last year we moved to Woolwich (the birth place of Arsenal FC). We have a large office with a separate workshop with a lot of room for activities and room to grow. We've had meetups in London, Munich, and Cambridge and a member-organised  meetup in Ohio. It's lovely to meet some of our members and guests in person, in a casual atmosphere for exchanging project ideas and random thoughts. 

When we put up the new sign!

Saar in the workshop ;)

In September we doubled our workforce by welcoming Ben Barwise, who started designing projects like Ananas and Whiteboard. More recently we started a 'Variety Show' YouTube channel, which will be more active this year.

Ben's first day.

Finally, it's natural for people to leave the Club. We found that when people do, it has little to do with our projects and service, but most to do with changing life circumstances. By far, most people indicate that they intend to come back.

When people cancel, they are asked to optionally provide an explanation. First they choose a pre-set category then have a text field to explain. We've taken 'Other' explanations and combined them to other categories where they exist. 'Planning on re-subscribing later' often has within it an explanation to do with time and financial reasons.

Looking ahead

We'd like to share the celebration with you in way of a £10 discount at our Club shop. Members can use this code at checkout


This code will expire March 9th. If you're not a member you can still use the code after signing up (the code won't work for memberships to the Club).

In the coming months we'll initiate a rewards programme where we send a small token of appreciation to members. For example, you'd get something with your first, tenth, twentieth project, etc. We really appreciate the people who stick and we want to show that appreciation somehow. We will also organise another London meetup soon. Details TBD. Otherwise things remain the same. It's working.

We're very encouraged by the responses we've received to this 'project' over the past two years and look forward to continue inspiring people with creative electronics for a long time to come.

I'd like to thank everyone who has supported us with encouragement and money over the past two years. Particular thanks to members who have taken an active role in suggesting and creating projects, community-related activities, and help with presenting our projects. It's a special kind of joy to know that we're creating something that genuinely inspire people, and an environment that encourages participation and engagement. Thanks for that.

Bob Widlar’s 723 chip toolkit adventures

Jenny List


Before we begin

This is an electronic project with the aim of taking the user through an interesting corner of the world of linear electronics while paying tribute to one of the greats of electronic design. Though like all Boldport projects it is aesthetically pleasing, it delivers its results in the form of voltages rather than lights or sounds. Thus alongside all the usual soldering tools it is probably essential that you have a multimeter or other voltmeter to hand to fully appreciate it.

The project contains a single surface-mount integrated circuit in a so-called “SOIC” (Small Outline Integrated Circuit) package. If you are daunted by the prospect of soldering an SOIC then never fear, a Google search should deliver plenty of tutorials for what is a surprisingly simple procedure. As well as the SOIC there is a power transistor, and while both semiconductor devices are fairly robust there exists a small possibility that they could succumb to damage from static electricity. Therefore we would like to suggest that you take some precautions against accidental static discharges when handling these devices.

Lastly, the μA723 datasheet is an essential companion to this adventure. Make sure you have it handy.


The Fairchild μA723 voltage regulator is not at first sight a particularly exciting integrated circuit. Designed by the legendary Bob Widlar and released in 1967, it should have followed the majority of its contemporaries and faded from supplier catalogues and parts lists during the 1970s as it was superseded by more capable devices. Instead it has persisted, and five decades later it can still be found in the product lists of several semiconductor companies. We’ll try to answer the question of why that is the case, and delve into its operation with a selection of circuits using it that you can try for yourselves.

Have a look at the functional block diagram on page 1 of the datasheet. The 723’s internals comprise a collection of parts from which almost any voltage regulator circuit can be constructed. There is a buffered voltage reference, a comparator (labeled ‘Error Amp’), a current limit transistor, and an output transistor that is only capable of delivering a modest power level. Except for the comparator output being internally connected to the two transistors, nothing is preconfigured: the designer is required to create their own circuit and is forced to think about the internals of a voltage regulator.

On the following datasheet page we see a much more detailed schematic of the internals. Normally, you wouldn’t need to follow the innards of the chip in this detail, but an interesting exercise is to identify the building blocks. The top left corner with the three resistors and two transistors, for example, is the Widlar current source. It allows the designer to achieve low currents without large value resistors, which were expensive and large as discrete components, and hard to achieve within an integrated circuit using the technology available at the time. What other blocks can you identify?

The appeal of the chip then is in this presentation of a blank canvas. Whether you are learning about voltage regulators for the first time or a seasoned designer seeking to push a regulator circuit beyond the performance confines of commonly available but less flexible devices, the 723 offers the required tools to achieve your goal. Unlike other survivors from semiconductor catalogues of yore such as the NE555 timer or the μA741 op-amp it does not have applications beyond the relatively narrow field of voltage regulation, but within that field it provides such a wealth of functions that it has justified its place alongside them as a classic among integrated circuits.

The functional diagram of the 723 from the datasheet

Principles of a basic
linear regulator circuit

Today, when we build a power supply it is likely that it will include some form of switching regulator. In simple terms, an LC circuit of some form is used as an energy store fed by pulses of electricity, and regulation is achieved by adjusting the length of those pulses in response to feedback from the output voltage. In this way voltages can be changed and regulated with maximum efficiency. Though the 723 datasheet includes a switching regulator application, it’s fair to say that in 1967 a switching regulator would have been considered something of a Space Age technology. Huge advances in transistor speed as well as in materials such as the ferrite used in the inductors have given us switcher modules that cost pennies, but back then they would not have delivered the performance we are used to and would have been beyond many component budgets.

Instead, a typical power supply of the day would have derived a rough DC from the mains through an iron-cored transformer and a bridge rectifier, with a large electrolytic capacitor for smoothing. The regulator, if there was one, would have been a linear design, an all-analogue affair in which regulation was achieved by varying the current flowing into the load in response to feedback from the output, and dissipating any voltage drop between rectifier and output as heat.

The key component of this type of linear regulator is a comparator. This is an amplifier with two inputs, that performs the simple job of deciding whether or not the voltage on one input is higher or lower than that on the other. If one of the comparator inputs is connected to a stable reference voltage and the other to the power supply output, the answer produced by the comparator can be used to say whether the output current should be decreased, or increased. If the base of a transistor in series with the power supply output is connected to the output of our comparator comparing the two voltages, we have built a simple but effective voltage regulator. This principle forms the basis of all linear regulator circuits using the 723.

We shall now move on to some real-life examples of regulators using the 723, and show how they can be built using the "Widlar" Boldport Club project. Before starting then, it’s worth taking a look at the kit itself with a quick description.

The "Widlar" Boldport Club project contents

The kit comprises a PCB and a pack of components that should allow you to experiment with a variety of linear regulators using the 723. It features a 723 in a surface-mount SOIC package rather than the classic 14-pin DIP. This device has been available over the years in a variety of packages from a metal can to a tiny quad flat-pack. The PCB meanwhile has been designed to be used as both a prototyping board and a base for a permanent regulator circuit. Aside from the IC footprint it also has holes, traces, and pads for placing a variety of different components and connecting them through jumper wires. There are no hard-and-fast rules as to which component might go where, and many circuits might not use all available holes. When building your circuit feel free to place components wherever you wish, as long as the connections are correct. We do recommend planning the layout before committing to it with solder.

Figure 1 from the datasheet in its original form on the left and in a physical form on the right.

A simple positive linear regulator

There are two basic 723 configurations, one for use when the desired output voltage is less than that of the 723’s internal voltage reference (Vref in the datasheet, equal to 7.15V), and the other for when it is greater. They follow the same principle of using a comparator to compare reference and output voltages, their only difference is that the lower voltage version derives its reference for comparison through a potential divider while the higher voltage one does so with the output voltage. (See the differences between Figures 1 and 2 in the datasheet.)

So this circuit is a straightforward linear regulator in which the output voltage is compared with one derived from the reference via a potential divider in the form of R1 and R2. These two resistors determine the output voltage, and we have supplied a pair suitable for a 5 volt regulator, as conveniently specified in Table 1 of the datasheet. There is another resistor, R3, which is not critical but can be calculated from a formula in the datasheet. We have supplied a 4.3KΩ resistor for this part.

An interesting refinement to the most basic regulators comes with Rsc, the current sense resistor. This is connected across the base and emitter of the current sense transistor, whose collector is connected to the base of the output transistor. When the voltage across Rsc reaches a point at which it starts to turn on the current sense transistor, the base of the output transistor is pulled down. This reduces the output voltage, and thus the current stays at the same level. The current sense transistor turns on with about 0.6V on its base/emitter junction, thus with a 10Ω value of Rsc the current is limited to about 60mA (using Ohm’s law).

Follow this diagram to create the 5V regulated output. This is one of many ways to lay out the circuit on the PCB. How interesting can you make it?

This should be a simple enough circuit to construct whether you wire the discrete components via the holes in the board or by soldering them directly to the exposed pads. A pitfall lies with R2 from ground to pin 5, it is all too easy to wire it to the wrong end of R1 on pin 6 by mistake. This yields the happy accident of the output voltage being the reference voltage plus a diode drop, or a serendipitous 7.23 volts, but is not the intended result.

Modern regulators are often designed to work from a supply voltage just above their output voltage, and are usually referred to as “Low dropout” as a result. In 1967 integrated circuit regulators were in their infancy, so the 723 requires a relatively high input voltage of between 9.4 and 40 volts to keep its internal 7.15 volt reference operating (see these and other handy figures on the first table on page three of the datasheet). Your input voltage for these circuits should be within that range, and when building our versions of them we used a 12 volt input.

Fixed 5V regulated output circuit example (note that the capacitor should be connected to pin2, not pin11 as shown in this image)

Fixed 5V regulated output circuit example ( note that the capacitor should be connected to pin2, not pin11 as shown  in this image)

Fixed 5V regulated output circuit example (note that the capacitor should be connected to pin2, not pin11 as shown in this image)

Making your regulator variable

Any voltage within the range available can be selected with careful choice of R1 and R2, so a variable supply can thus be created by replacing them with a variable resistor. This is a technique that should work with both the high and low voltage variations of the basic linear regulator circuit, we have shown you the high voltage version for voltages above 7V. A small 10KΩ trimmer (a variable resistor) is in the parts pack for this purpose, along with a pair of 470Ω resistors to place at its ends.

Building this circuit should be simple enough, the fixed components share very similar placement to those in the previous circuit while the variable resistor can be placed in the appropriate set of holes to the left of the 723 and linked to the rest of the circuit by the 470Ω resistors and a piece of hook-up wire. Upon power-up you should find the output to be adjustable from somewhere just above 7V to just below whatever is the value of your input voltage.

Higher current pass transistor

The 723’s internal transistor is only a modestly powered device, so in order for a 723 to provide juice for more demanding circuits an external transistor must be used. The 723 output drives its base directly, and its emitter feeds the current sense resistor. It is important that the pass transistor has sufficient gain to ensure that the base current drawn from the 723 for the desired output current does not exceed the 723’s 150mA maximum output current as specified in the datasheet. Larger current outputs may therefore adopt a Darlington pair configuration to reduce the current from the 723. We have supplied a BD239B NPN pass transistor in a TO-220 package and a 3Ω current sense resistor to deliver a current limit of about 200mA. Building this circuit should present few challenges to someone who has already made the previous two circuits. The power transistor should fit in the set of holes at the top right of the board, and care should be taken to observe its correct connection.

In a series linear regulator such as these, the energy involved with the voltage drop between input and output at whatever current is being drawn will be dissipated as heat in the output transistor. Even at the fairly modest 200mA current limit set by that 3Ω resistor, there can be enough energy involved to heat the transistor to the point at which it fails. You can easily demonstrate this using the circuit, when you short its output through a suitable ammeter you will see the current remain stable at just above 200mA but if you place a finger on the transistor you will find it rapidly heats up. We couldn’t hold a finger on the transistor for more than 15s in this configuration, and we would strongly recommend that you do not operate it in this way for longer than that time.

The solution to allowing higher currents without destroying the transistor is to add a heatsink, a device designed to conduct the heat away from the transistor and dissipate it. And since there are a bewildering array of heatsinks available it makes sense to have some knowledge of the factors surrounding heatsink selection.

Variable output voltage with transistor

The efficiency of heat transfer from the semiconductor junction to the atmosphere is expressed through a thermal resistance in °C/W (degrees in Celsius per Watt), where for example a heatsink with a 10 °C/W rating will rise in temperature by 10 degrees for every watt of power that pass through it. Commercial heatsinks will all provide this figure as part of their data sheet, and even semiconductor packages will often include it in theirs. The TO-220 package of the BD239B included in the kit of parts for example has a thermal resistance to the atmosphere quoted in its datasheet of 63 °C/W, meaning that with no attached heatsink it will rise in temperature by 63 degrees for every watt of power it dissipates. The full calculation takes into account such factors as the room temperature or the efficiency of the bond between the transistor and the heatsink, but for our purposes here a more back-of-an-envelope calculation should be sufficient to gain an angle upon it. Assuming our regulator is taking a 12V input and is shorted out with the current limiter holding it to 200mA, we can therefore calculate a temperature for our experiment holding a finger on it. The power P=I*V, is 0.2Ax12V, or 2.4W, therefore the temperature should eventually reach 2.4x63, or 151.2 degrees. The datasheet shows a maximum junction temperature of 150 degrees for the device, so running continuously in that configuration would cause it to fail.

Selecting typical clip-on TO-220 heatsinks, we find a variety of parts with quoted thermal resistances of around 25 °C/W. If we were to attach one of these to our transistor and repeat the calculation, we would arrive at a temperature of 2.4x25°C, or about 60 degrees. It would still run quite warm with such a heatsink, but not to the point at which the transistor would fail.

A switching regulator using a 723

The μA723 is a linear regulator kit-of-parts as we have described, but its operation is not solely limited to that task. As you might expect, as an analogue integrated circuit it can be configured as an oscillator with the application of some feedback, and the resulting oscillations can be pulse-width-modulated according to the difference between the voltages on the input of its comparator. It can then be used to drive a straightforward buck converter with a suitably fast diode and inductor combination, and you can find the circuit diagram in figure 9 of the data sheet. (The Texas Instruments μA723 data sheet has an error in this case, the collectors of both transistors should be connected together. Compare with the TI LM723 sheet.) It’s by no means the circuit you would choose for a switching regulator today as far better switching regulator controllers exist, but it must have been a particularly impressive application back in 1967. The Widlar kit does not include all the components to make this circuit, but it is included here simply to demonstrate the versatility of the device.

The circuit uses a pair of PNP transistors, a fast rectifier diode, and a small inductor. The discrete semiconductors from the 1967 datasheet have long ago been superseded, but fortunately over the decades since we have seen a multitude of better and faster devices replace them. If the more up-to-date alternatives on the most recent Texas Instruments data sheet are not available then you should have few problems finding equivalents.

The inductor is specified on the data sheet as a particular number of turns on a specific core, but yet again the benefits of the electronic component supply chain are in our favour and there are plenty of 1.2mH inductors on the market designed specifically for use in such converters. We used a TDK wire-ended component for ours.

The construction of the switching regulator follows a similar pattern to those of the linear regulators. Care will have to be given to the order of the leads on the transistors and to place the diode in the right orientation, but otherwise it is simply a case of placement of resistors. The same values for the potential divider can be used as with the linear regulators, so you can use the same resistors as in the earlier example to make a 5 volt regulator.

Making a bench power supply

With this project you should have created a perfectly serviceable voltage regulator that can serve as the nucleus of a useful bench power supply should you choose to take it further. Searching the Internet will lead you to plenty of projects showing suitable circuits containing a mains transformer, bridge rectifier, and large smoothing capacitor to deliver a rough DC supply as your input voltage. If you take this path, we would suggest that you build either of the linear regulator circuits with the variable resistor option, replacing the trimmer with a full-size potentiometer which can be mounted on the front panel of any enclosure you place the circuit in. If you produce the version using the pass transistor you will definitely need a suitably large heatsink as explained above, and you may wish to pick a current sense resistor to give you a higher current limit. A popular choice is a 1Ω resistor with a power rating of greater than 0.5W, this delivers a 600mA current limit which is high enough to be useful but low enough to cause little harm in the event of a short circuit. Please exercise caution with the mains voltage wiring as you build it, and enjoy a useful bench instrument which should last you for many years.

The changing face of
Horowitz and Hill

If you are building this kit, there is a strong chance that somewhere close to your bench you have a copy of The Art Of Electronics, the seminal undergraduate text by Paul Horowitz and Winfield Hill. First published in 1980, with a third edition published in 2015, it remains a text that electronic engineers do not discard at the end of their university courses. We know engineers still using their over-30-year-old first editions as works of reference, it’s that useful a book.

As you would expect from an electronics text book, Horowitz and Hill has an extremely useful chapter on power supplies and regulators. Because of the handy kit of regulator parts it contains, the μA723 is used as the teaching example by the book.

Near the start of the chapter in the first edition, the authors introduce the chip thus:

“The μA723 voltage regulator is a classic. Designed by Bob Widlar and first introduced in 1967, it is a flexible, easy-to-use regulator with excellent performance. Although you might not choose it for a new design nowadays, it is worth looking at in some detail, since more recent regulators work on the same principles.”

First published only 13 years after the chip’s debut, this seems to be a damning indictment of its future prospects, and nine years later in the second edition the paragraph appears unchanged.

In the 2015 third edition though, they have the good grace to eat their words and say the following, before listing the chip’s virtues:

“Lest we leave the wrong impression, we hasten to remark that rumours of the death of the vintage 723 were greatly exaggerated. We have been using dozens of linear regulated power supplies manufactured by Power One for more than three decades without a single failure. All of them use the humble 723 regulator chip, as do other OEMs”

This remarkable component has confounded even the seminal text in its field, though it’s fair to observe that to have so many engineers learn about regulators in this book through the one chip certainly does no harm to its prospects.

One chip: many datasheets

Any references to a data sheet in this document relate to the Texas Instruments SLVS057D document for the μA723. There are many 723 data sheets from the multiple sources for the chip which contain similar information, and to seek them out is to both explore five decades of the semiconductor industry’s corporate history and examine the way that dissemination of information to engineers has evolved over that time.

Our earliest copy comes from the original source, the Internet Archive holds a Fairchild Semiconductor linear integrated circuits data book from the early 1970s (see section 5-2). It sits alongside some other familiar Fairchild greats such as the μA7805 and μA741, but also in the same book as drivers for magnetic core memory, AM car radio chips, and colour TV decoders. In the days before easy access to any data sheet via the Internet, these books that could be had from semiconductor sales reps were highly prized and much read, spawning an intimate familiarity with a manufacturer’s range that is much more difficult to gain from a website.

Fairchild Semiconductor passed through a variety of owners over the decades, first Schlumberger in the late 1970s, then National Semiconductor in the following decade, then independent again, and finally disappearing into the ON Semiconductor behemoth. ON Semi do not appear to list the μA723 as a current product, but through Fairchild’s corporate history there are sheets from the National Semiconductor days to be found.

The μA723 production from Fairchild and its descendants form only half the story, for the chip was produced by many secondary manufacturers. Here a cursory Google search will find data sheets from ST, Texas Instruments, and JRC among others. TI even have two completely different data sheets for two different part numbers, a μA723 and an LM723, that have probably arrived in the TI empire by the means of different corporate acquisitions.

Reading the different versions of the same data sheet from so many different sources over the years it has been extremely interesting to spot the differences between them, and uncover quite a few errata that have crept in as they have passed through many corporate publishing departments. It is perhaps unfair to single out the worst offenders as their offerings are no longer currently manufactured, but we have found missing figures referenced from text, figures with the wrong labels, and schematics with glaring mistakes. Even the current Texas Instruments μA723 sheet that we have used as a reference for this document has some minor mistakes in the schematic for the switching regulator, the collectors of the two transistors should be connected to each other.

So take a while to lose yourself in the datasheet for the μA723, but be careful, some sheets are better than others!

Bob Widlar

The "Widlar" project pays tribute to the designer of the μA723, Bob Widlar. Widlar was a person whose legacy is defined not only by his huge contribution to the art of linear integrated circuit design, but also by his larger-than-life reputation as an eccentric and prankster. The picture of him that surfaces most often is one of a bearded man smoking a cigarette, holding a beer, and giving the photographer the finger, with the caption expressing his contempt for digital electronics: “Every idiot can count to one!”.

His career with Fairchild began in the early 1960s, and he brought to integrated circuit design an approach that treated it as an art in itself rather than simply a miniaturisation of existing full-size designs. To overcome some limitations involving passive components that could not be replicated on silicon he developed circuits which have since become the standard components of linear integrated circuit design. Some of them bear his name, for example the Widlar bandgap reference, or the Widlar current source.

While at Fairchild and during his later time at National Semiconductor, he was responsible for the creation of a variety of groundbreaking chips, some of which like the μA723 were destined to become defining standard components of their class. The μA702 of 1964 for example was the first monolithic op-amp to market, with the then-revolutionary feature of integrating all components except the optional frequency compensation parts with no hybrid construction on the same piece of silicon. Following his move to National Semiconductor he continued with the first 3-terminal voltage regulators, the LM100 series, and then the first op-amp requiring only a single capacitor for frequency compensation, the LM101. In 1970 he left National Semiconductor and famously became a recluse in Mexico, before returning to the industry a few years later as a contractor. He spent some time with Linear Technology in the early 1980s, and finally passed away in 1991 of a heart attack aged 53 while jogging near his Mexican home.

If Widlar’s professional achievements tell us about his career, it is the larger-than-life legends that survive which tell us about the man himself. There is a famous episode in which he brought a sheep to the National Semiconductor offices and tethered it on the slightly unkempt lawn, there are tales of his wild drinking escapades, and of his electronic devices designed to annoy noisy colleagues. That we are celebrating him with a kit so many decades later probably owes as much to this aspect of his character as it does to his work, it is probable that only when the semiconductor industry was in its infancy could he have found such a place within it.

One concise quotation about Widlar from someone who knew him stood out for us:

“Bob Widlar never talked about his early years, or anything personal. He was very charming but always a bit mysterious. He seemed to be more artist than engineer; he cherished creativity more than the concept of general intelligence.”
─ Bo Lojek, History of Semiconductor Engineering

Credits and license

This article was written by Jenny List with contributions from Saar Drimer. It is licensed under the CC BY-SA 4.0.

We don't do holiday projects

Saar Drimer


It's tempting to create holiday-themed projects for the Boldport Club. People suggest that to me quite often. I've decided not to do that; here's why.

Not everyone celebrates Christmas
Or Hanukkah or Ramadan or Pastover. Or any of the other shopping-motivated 'holidays' (I'm looking at you, Valantine.) Not everyone lives in the northern hemisphere and associates Spruce or Fir trees with Christmas. My southern-Brazilian friends associate Christmas with beaches and camarão, for example. We have members from all over the world; why would I presume?

Everyone is doing it, so I'm generally not interested. It's easy, it's obvious, and it's been done. I feel the same about NeoPixels, by the way.

We start planning projects four to six months in advance. We order the production boards (ideally) 90 days ahead of shipping, so we need to nail down the amount we'll build then. We create a fixed amount of stock for each project and won't make more. Normally we try to project how many members we'll have by the time we ship plus about, say, 100. (We used to do a lot more, but then we got stuck with a lot of stock to shift. Anyway.) This means that whatever date-specific project we don't ship, no one would want until next year. That's no good.

The realities of shipping world-wide is that it can take up to a month to get to someone — we've had much longer! So if we want to hit a specific date we'd need to ship the project at least a month before, possibly two depending on the date of the holiday. Some people will receive it way too early and some won't receive it in time. People would want, justifiebly, to swap projects. All that kind of sucks.


Part of the intended appeal of our projects — whether obvious or not — is that they are 'timeless'. I don't mean this in a pompous kind of way. Our projects will be as enjoyable in five or ten years as they are today. TAP, MOSTAP, and the upcoming Widlar are based on circuits that are 40-50 years old! You cannot say that about a Raspberry Pi or Arduino you buy today and use years later, twenty generations behind, stale and inadequate.

So now you know :)

Failure is definitely an option

Saar Drimer

Failure is part of getting better, at anything. Failures are markers in our journey towards expertise, ones that are often more memorable than the successes. The Boldport Club has many members that are engineers by profession (I am one too!); they are here, I think, for experiencing electronics in a different way that they do in their day-to-day work. My goal is to give them this experience. (See Limor Fried say 'I love these kits. Finally someone is making kits for me', which was delightful to hear.)

While I don't market the Boldport Club for beginners — in fact, I intentionally don't target anyone specifically — I leave the door open for them when they peer in. It is a unique kind of pleasure seeing someone who hasn't done any soldering, or has only dabbled, graduate to surface-mount soldering through Boldport Club projects with the support our wonderful community on our members-only Slack. My goal is to provide these experiences too.

Beginner, expert? The 'contract' is that you accept that there will be failure and that a non-trivial part of the experience will be frustrating (welcome to the life of an engineer!). You'll need to ask for help, embrace failure, share it, and by doing so improve. You will be challenged. I will support you in this process; if you do fail in building a kit and share it with the community so that we can learn from it, I will gladly send you a replacement in order to practice again. That's why you're a member of a Club that cares about your journey.

A case study of designing a trophy for engineers

Saar Drimer

ElectronicsWeekly and RS components have contacted me earlier this year to design a trophy to be awarded to the 29 winners of the Bright Sparks 2017 programme at the beginning of May. This is a first in what will become an annual event.

It was a given that the trophy would be made of circuit board material since this is what I specialise in. The brief was completely open except for a unit cost. More generally, EW and RS were interested in something that stands out from typical trophies one can get anywhere. For me, the challenge was to create an item that naturally sits on an engineer's desk and that is the least likely to be forgotten in a drawer. Moreover, I wanted this trophy to spark a conversation about creativity in engineering generally, and at the engineer's workplace.

Already during the initial phone call with EW I knew that some elements of circuit board manufacturing could fit well here: ENIG (gold) finish, edge plating, and detachable panelised elements. Initially I sketched concepts where the three pieces came as a panel — the main body and two smaller stand pieces that will slot into the main piece, and then soldered in place by the recipients. This would have given them an active part in assembling the trophy, an experience that they could never have with a traditional trophy.

First concept sketch. A panel to be assembled by the recipient with a detachable medal. Here I already had concerns about how to reattach the medal once it has been removed.

First concept sketch. A panel to be assembled by the recipient with a detachable medal. Here I already had concerns about how to reattach the medal once it has been removed.

Second concept sketch. Adding metal backing would add weight and could solve stability, assembly, and reattachment of the medal.

Second concept sketch. Adding metal backing would add weight and could solve stability, assembly, and reattachment of the medal.

I viewed the trophy itself as a stand for a 'gold' medal that could be detached and be placed back. So while the trophy as a whole will attract attention from afar, the medal itself is the centrepiece.

I often use a cardboard mock-up to check stability and physical appearance. This image was sent to EW and RS for approval.

I often use a cardboard mock-up to check stability and physical appearance. This image was sent to EW and RS for approval.

A typical trophy would be quite heavy. Weight is sometimes how we intuitively associate value with. The finished article needed to weigh around 300g, and for that I knew that I needed to add something heavy to the piece, as the circuit board a alone (about 15cm in diameter) would only weigh about 100g, even with the use of 2.4mm thick circuit board.

I started looking at stainless steel backing. Together with screws and nuts — which gave the piece some depth and an industrial look — I could reach 300g.

At this point I re-evaluated the 'delivery-as-a-panel' concept as it

  • would make it hard to display, like they did at the event;
  • would need to come with some instructions;
  • may never be assembled; or
  • may be assembled poorly.

I also realised that with the metal backing and a thick bracket I could both have the weight I wanted, lower the centre of gravity for better stability,  and create a robust construction without soldering. That sounded good.

By coincidence, we had our first Boldport Club meetup in London just when I was finalising the outline of the circuit board. There, Mike Harrison mentioned — without knowing about this project — that he uses a 'trick' where he adds ridges to slots that could be easily filed away if the dimension isn't quite right. Since I had only one go at this I adopted this idea. It turned out to be quite helpful as it allows very fine adjustment during assembly, as there is some tolerances in PCB outline routing.

The view of the top layer from within Inkscape using  PCBmodE . Notice the ridges in the outline's slots.

The view of the top layer from within Inkscape using PCBmodE. Notice the ridges in the outline's slots.

View of the bottom layer.

View of the bottom layer.

Once I had the final outline of the circuit board my friends at Aeguana, with whom I share an office, helped me with modelling the trophy and generating the files for a metal fabricator.

The mechanical drawings by  Aeguana  helped get the dimensions right for the metal work.

The mechanical drawings by Aeguana helped get the dimensions right for the metal work.

For PCB fabrication I chose Garner Osbourne. They are a UK manufacturer and I've been impressed with their top quality PCBs in the past. I knew that they do 'edge plating', which is something that I wanted to use in my previous designs but never had a chance to. ('Edge plating' can mean several things; here it's carefully routing through plated holes to leave finished copper on the edges of the PCB.) This was a good opportunity to both work with them and gain experience with this manufacturing technique. It was very helpful to have a direct line with their technical staff to make sure that I designed the board correctly for their maunfacturing process.

The back of the trophy. The main body and stands have a 1.5mm thick stainless steel backing attached with M3 screws and nuts. A custom 3mm thick stainless bracket holds everything together and adds weight. The position of the bracket also lowers the centre of gravity so that the piece sits solidly on the surface.

The back of the trophy. The main body and stands have a 1.5mm thick stainless steel backing attached with M3 screws and nuts. A custom 3mm thick stainless bracket holds everything together and adds weight. The position of the bracket also lowers the centre of gravity so that the piece sits solidly on the surface.

My aim with the design itself was to use elements that I would otherwise use with a functional circuit. There are pads, tracks, plated holes, and a hatched pattern that's called 'thieving' (this more evenly distributes copper on the board for the plating process). The exposed and covered tracks connected to the pads on the edges is meant to look like a network switch. The medal is made with the reverse of exposed copper and soldermask as one would normally expect, using the soldermask as a colour accent over gold. I've used this technique before for the 'tiny engineer superhero Emergency kit'.

I delivered the trophies under budget and on time, which is always a nice outcome for all involved. The event took place in early May at the Houses of Parliament in London and I understand that the recipients liked what they've received. I wish them the best and I sincerely hope that they do not put the trophy in a drawer any time soon!

All the best to the recipients of the award!

All the best to the recipients of the award!

Beyond square and green

Saar Drimer

The TAP , a  Boldport Club  project featuring a TI component.

The TAP, a Boldport Club project featuring a TI component.

Last time I sat to write this blog post I ended up writing a story about the borderline abusive nature of some of the kits and tools engineers use, ironically supplied to us by semiconductor companies who would like us to evaluate, and develop with, their components. My point was going to be that as an industry we can do much better in this area and here I'll describe how.

If there was semiconductor heaven, companies would get as many multi-million-unit orders as they can handle with the minimum amount of pre-sale costs and minimum support (also 100% yields, their own fab, and no distributors, but perhaps even heaven cannot manage that!)

The Cuttle , a Boldport Club project featuring an ATMEL MCU.

The Cuttle, a Boldport Club project featuring an ATMEL MCU.

Since there is no heaven, semicon companies and distributors make an effort to entice engineers to evaluate, switch, or become aware of their products in the hopes that one of those leads will eventually become a multi-million order. Part of this effort culminates in embarrassingly bad videos, vital documentation behind a registration-wall, vital information behind a distributor-wall, or really hard to use hardware. Whilst I can only whinge about the former few on Twitter, I can actually help with the latter. I've dedicated a few years of my life to exploring this space, even writing my own PCB design tool to do a better job at it.

Let's take evaluation kits. Ideally, we'd like them to

  • Be well presented and evoke a sense of purpose, curiosity, excitement, and anticipation;
  • be easy to use — from unpacking to useful within minutes;
  • demonstrate the unique features of the product very well; and
  • be memorable, useful, appealing, and worthy of sharing with others. 
Touchy , a Boldport Club project featuring a SiliconLabs MCU

Touchy, a Boldport Club project featuring a SiliconLabs MCU

These properties demonstrate great care for the engineer's time, and project a modern approach to user experience (as opposed the what we get from the tradition of 'walled favelas' and an entrenched lock-in culture). It's clear to me that respecting engineers through hardware, documentation, and tools has great positive impact on brand association.

Unfortunately, most kits I see out there fail the points above. They are more likely to end up in a drawer, cursed at, or smashed than be on an engineer's desk when they are designing in components for a new project. They are also much less likely to be shared with colleagues or on social media.

OK. Maybe it's not so bad, but we can certainly do better.

PissOff , a Boldport Club project featuring an NXP MCU

PissOff, a Boldport Club project featuring an NXP MCU

I'm an engineer, but my approach to hardware has changed over the years. From complete focus on function early in my career, to treating form and function with the same import. I argue that considering form as early as spec'ing functionality invariably leads to more effective designs. This is the method we apply to all our work at Boldport.

The Matrix  is a  Boldport Club  project kindly sponsored by  AMS  and  Eurocircuits .

The Matrix is a Boldport Club project kindly sponsored by AMS and Eurocircuits.

I cannot share ongoing work with semiconductor companies who have bought into this narrative, but here's a recent public example.

I've designed The Matrix as a soldering kit for the Boldport Club and sent it to over 430 members last month. It is designed around AMS's very capable AS1130 LED matrix driver, which AMS kindly donated for the project. Eurocircuits, my go-to PCB fab, also kindly supported the project through sponsorship. After having a Boldport Club membership this kit costs £17.

Putting the soldering bit aside — eval and demo kits come assembled — let's evaluate The Matrix against the criteria above. It's packaged neatly in a multi-purpose box that's normally used for jewellery. Once soldered it's immediately useful with any platform that can drive an I2C peripheral — Arduino, Raspberry Pi, etc. — helpfully Boldport Club members have written comprehensive open source drivers for the chip (Arduino, Python). It can work with any OS; the kit itself does not require any special drivers or software. It simply and effectively demonstrates the features of the chip, nothing more; it's not over-engineered. It's useful and fun — just look at what Joey Hagedorn did with it. (I'm pretty certain that this one won't go into many drawers.) Finally, the design is open source hardware so that engineers can easily use it in their projects.

Now compare this with the existing $249 AS1130 demonstration kit.

I encourage companies to think about their target audience's time and mentality. We engineers have very acute sense for marketing spin; we want to get stuff done effectively, but we also like playing with 'toys'. Understanding and factoring this and other 'engineering culture' aspects into a complete experience journey with a product is vital for a successful launch or promotion of a product, even if it's a humble eval kit! Those companies who understand that will undoubtedly benefit from this refreshing approach.

Of course we can help companies with all of that at Boldport, and we'd like to work with you to make this happen. But being an end user of some of these products, I'm generally more interested in better tools for engineers, whoever ends up designing them.

Juice , a Boldport Club project featuring a TI component

Juice, a Boldport Club project featuring a TI component

A fictional story in square and green

Saar Drimer

So I walked down the endless aisles of a large trade-show full of companies selling electronic components. The company I work for sent me here. I'm wading past dozens of them seeking something that catches my eye. They all sell basically the same stuff but with a slight twist that's promoted to 'game-changing' by marketing. Slightly less power here, slightly lower cost at 1M+ units there, slightly longer detection range in the rain, or slightly more robust on Tuesdays. Stripping down the flashy branding everything pretty much looked the same. Not to make this a waste of time and my employer's money, I decided to talk to a few of them. In the process I picked up a couple of evaluation kits. They were the typical 'square green and boring' fare and certainly not something I'd tweet a picture of or show the gang back at the office. It's as if they didn't care that they look and feel like they came from the 90s. Well, I'm kind of used to that; a lot of stuff I use in engineering looks this way. Anyway, there's a remote possibility that these eval boards become useful, but they're drawer-filler material and everyone knows it.

Months later I got an assignment and while looking for an evaluation kit for a chip, I remembered that I have one in my drawer! That drawer is full of these poor neglected evaluation and development kits that I've never touched. I feel sorry for them sometimes. I know that it's strange to feeling sorry for electronics, but there you go. That eval board had the previous generation IC on it, which is mildly annoying. I like having the latest stuff but to save the company some money I decided to try and make it work.

It came with a USB stick that miraculously survived the journey, and even more of a miracle is the fact that it's still next to the board! Damn. Windows software and I run Ubuntu. ("What if the stuff on this stick is malware? That could be a great vector to infect my machine. At least it's not a WindowsXP CD any longer because my laptop doesn't even have a drive for that.", I remember muttering to myself.) As the ritual goes I then spent two hours setting up a Windows virtual machine and fought it to recognise the USB1.1 device through the USB3 host port. What made it work eventually was plugging it through a USB2 hub. Go figure. I tamed the machine but it didn't feel like a victory at all.

I fired up the software. It asked for my contact details so that it can email me an activation code. Craaaap! Those pesky market-y types even made sure that it won't accept addresses. "Why should I need to give them my details to evaluate their product?! It doesn't make any sense!", I shouted internally. Then I calmed down. I got the activation code. I cursed at the two marketing emails. I activated the software. The relationship with this vendor hasn't started too well. They're abusing my good will from the get-go.

Yup. The software couldn't talk to the evaluation board as it needed some drivers that are bundled with the manufacturer's custom IDE. The firmware also needs to be updated otherwise the thing won't work. I spent another couple of hours downloading and installing the IDE. While I waited I realised that this 'kit' felt more like a punishment than a gift and I started regretting my decisions at the show, much like what I imaging a Brexit voter feels with the rising cost of Marmite.

OK. It worked. All of this so I could move my hand in front of the thing and see numbers change on my screen. I guess that all of that was worth it. Well, hell, I'm actually pretty sure that it wasn't. I couldn't conveniently use this board because idiotically the sensor was in the centre of the board instead of a protruding edge where it might be useful for evaluation under other conditions. The I2C pins weren't conveniently exposed and I completely lost the motivation to go to the soldering station and hack on it. This shit should work out of the box! I ended up buying a £249 'development' kit from a competitor that was only slightly better. That shows me for trying to save money.

Now, if only they exposed the I2C pins through a header, put the IC somewhere sensible, and made some drivers available for Arduino or whatever, I could have just used it straight-away. But, no, they have to always create this 'walled favela' around their products. The lock-in is strong with this industry, you know. I'm starting to be fed up with 'them' not thinking about these sort of things. Next time I'm going to try to give 'my' business to a company that gives me a good experience — like decent datasheets, complete footprints and usable boards! — even if their devices are a bit more expensive. Unit cost is not all that should matter... the design experience should too.

What Boldport Club members say...

Saar Drimer

A few months ago I've asked members — and x-members and everyone else — to fill in a questionnaire. I wanted to learn a bit more about who members are and what they thought about the Club, projects, community, value, cost, etc. The questionnaire is still live if you want to fill it in.

I've also asked those who indicated that they are members to provide a public quote that I could later use on the website. I'm refreshing so I just had a read through all of them in one go again. It made me feel really pleased with how the Club turned out, a year after conception. Even more so, it fills me with great joy to know that people appreciate the effort that I put into the work and that it has touched their lives. Thanks to all of you who take the time to write to me about what my work means to you. In turn, that means more than you can imagine to me.

Below are all the quotes that I've received, as I received them. Add more in the comments if you wish.

I never knew a soldering project could be beautiful!
— Happy BPC Member
As someone without any background in electronics or engineering, I was skeptical as to whether the Boldport Club would be fit for me. However, the stunning designs and the pleasure I get from building, documenting, using and even troubleshooting the projects together with other Club members soon made playing with electronics something I’m proud to call a hobby now!
— @Lophification
Boldport Club is the best source for pointless beauty, thought-provoking circuits and plain-old soldering practice in the world. I am thrilled to have an opportunity to experience all that plus the excitement of getting fun stuff in the mail every month.
— krisjaniz
I have long thought about learning more about electronics and this was a great format. The projects have taught me a lot of practical skills and the community is one of the most helpful, open and engaged I’ve ever encountered.
— Calle "Zeta Two" Svensson
I was taught electronics but I have never really understood it. Now I can solder, dimension a low-pass filter, program a microcontroller. This is just the beginning!
— Ronan
The projects are beautiful and so well thought through they are a joy to solder and assemble. Once they are built they are so many ways you can hack on them and play with them. On top of all that there’s a community built around the club with great people.
— Adam Bregenzer
Being a member has been awesome for 3 reasons -
1) I get to keep adding to my collection of PCB art from various designers.
2) I get a fun and interesting electronics kit each month without having to track down missing componants or have to submit files to OSHPark for my own boards. You get everything you need!
3) Its been super cool as a tool to help me teach my niece and other family members about basic electronics (and not so basic), which has been really positive!
— N.Pearce
The Boldport Club’s projects are nothing short of art. As well as teaching me valuable lessons about physics as a student, I really believe they encapsulate the spirit and the essence of kit building.
— Archie Roques — a young maker
You know when you get a vacation, a tropical island where the drinks on the beach come with little parasols? Yeah, me neither, but clever circuit boards are pretty cool, though.
— nocko
The Boldport Club provides a rich and engaging learning experience. I really enjoy receiving the projects.
— KR
As long as I receive the beautiful projects from Boldport I am sure the world hasn’t ended and the good is going to win in the end. Because the projects were manufactured with love and this is what you get to see.
— Member from Berlin
I’m a brand new member so have only just completed my first kit, but what I found irresistible about Boldport Club is the combination of electronics fun and self-education, packaged in an elegant regular monthly project, wrapped in a thriving and supportive community.
— Delighted New Club Member
I know I’ll build at least one circuit that works every month! And, it will look cute!
— whitequark
It’s Art. It’s Fun and it’s a challenge! Be a f**ing soldering electronic hero! :-)
— alias
The best part? Receiving a surprise box in the mail which gives me some quality time with my soldering iron and ends up in a beautifully designed piece of electronics, that even my girl find attractive.
— Toby Aumüller
A little time to myself...
— Anonymous
Strangely shaped boards with peculiar layouts that awaken your curiosity in electronics!
— Marc
As someone not good with electronics, I always learn from these projects and they are creatively designed so I have fun completing them.
— Conor Patrick
As someone just delving into the world of electronics the Boldport projects are challenging but incredibly rewarding. I have been impressed with the high quality and the beautiful design of each project and learn something from every one.
— Anonymous
After looking for solder kits that are beyond the “learn how to solder” ones out on the market, Boldport really helped satisfy my love for kit builds since it’s a unique service.
— Daniel Lukach
Saar offers another Engineering trade off for us to challenge our output. Are we always focused on putting out the cheapest, or smallest products? It’s time we put back form and function in our designs. Saar balances aesthetics in with cost, sourcing, size, scale, power etc. Sure it’s harder but that’s why we call it engineering and when it all falls into place you know it because it ‘feels right’!
— Mike Baranowski
Gained confidence that I can build ANYTHING by hand, even though I have years experience in the field as a professional. Great projects I cant find anywhere else.
— @F4R4D4Y.DC414
Once a month I get an interesting package from Britain that stretches my imagination and skills. After spending a few hours with a hot soldering iron I end up with an elegant bit of kit that I can show to family and friends to puzzle and delight them.
— Shoultz
“Want to finish that board?” “When time and enthusiasm has failed you” “boldport worthy of that center place in the display cabinet” Scratches the itch. The above semi cheesy marketing tag line thing says it all for me... mostly.
— Anything goes...
Ever looked for a DIY electronics kit subscription with projects which are not only cleverly designed, nicely documented but also very artful and sometimes challenging? Look no further, Boldport is exactly that!
— Which ever you prefer. ;)
The best part of the Boldport Club is knowing there are other people just like you out there.
— Alex Hitchins
I love being introduced to new and interesting parts through Boldport Club and the real-world projects they provide.
— @gareth__
Simple, quiet fun and “I built it” bragging rights
— Ted H
For anyone who enjoys building electronic circuits this is a great way to keep in practice and have some artistic conversation pieces you would not be afraid to put on the coffee table.
— Lawrence, Buranby, BC
Beyond the tangible aspects of the club, the (Slack) community adds immeasurable value to the membership. For any electronics enthusiast — be it the experienced professional through an amateur hobbyist — this is much, much more than a kit in your mailbox each month.
— Keith
I’s fun, it’s interesting and you wait for the next project.
— Robert Schwarz
I have the feeling I am part of a very interesting project going on
— GW
Small, but not simple, beautiful shapes in the form of kits that every month will teach you not only electronics and design, but without knowing it, what is to be human.
— Jorge A.
I really enjoy building electronics kits and learning new things. Boldport Club satisfies both.
— Anonymous
BoldPort has taught me that the hardware guys and gals have it just as hard as us software guys and gals... especially when it comes to soldering header pins on straight.
— MyztikJenz
The Boldport Club is a community of engineers and makers who appreciate the beauty of design hidden inside the devices that make our lives easier and more efficient every day. If you enjoy looking inside computers, taking apart phones, or fixing appliances, the Boldport Club might just be the place for you.
— Corey Shuman
Even practising engineers feel a disconnect between creative arts and technical work. The Bolport Club serves as a reminder that these are two sides of the same coin.
— Domenzain
A confluence of art, design, science humor and whimsy from an imaginative maker. Tinkering for fun, knowledge, and blinkly stuff. There’s a blurb for your book jacket.
— Zeke from Philadelphia
As a hobbiest, the regular high quality kits are a lot of fun to assemble and it is very fulfilling to receive a steady stream of projects to complete.
— merk

Boldport Club changes 2017

Saar Drimer

Hello Boldport Club members,

It's been over a year since I've announced Boldport Club. With more than 400 members and ten projects shipped I've learned a lot about a lot. I've had a clear vision for what I wanted to achieve and that remains as strong as ever; it's definitely working. How to achieve this vision changes with the parameters and time: the financial climate, number of members, availability of staff, availability of materials, my own availability, and many other factors.

During the two-month shipping pause I've decided to make some changes to how the Club operates. These are operational changes not changes in substance. Those changes are based on what I've learned through doing and also from what you've told me. The changes also reflect the maturity of the Club and it advancing from an experimental phase to something that will be running for a long time. That requires adjustments.


The monthly cost of a subscription is rising to £19 per month, still billed in three-month cycles at £57. This still includes taxes and shipping to where ever you are. The cost of projects at the shop will also increase.

A plummeting Pound and a near universal increase in prices by my suppliers pretty much forces me to take this administratively burdensome and possibly unpopular move. But I'd like to point out two things while I'm on the topic. Firstly, the original price was on the low side while still giving great value. I'm convinced of this because nearly all who responded the questionnaire — about 100 members — expressed that the Club provides good value for money. Also, remarkably, the churn rate has consistently remained under 4%. Secondly, the price that you pay is not only for the projects; it funds the concept that drives the Club and gives me resources and breadth to experiment, expand, and make exciting things happen.

The new membership price will be applied on the next renewal of your membership. This is done automatically; you don't need to do anything. Billing happens on the 28th of each month, so the month that this happens depends on when you last paid. To see when your next renewal is, log on to you account and check. If you don't want to be billed at the new cost, simply cancel the subscription before the billing date, and you'll only receive the projects that you paid for.

New subscription structure

There will now be only one membership option — a single project a month. To receive multiple instances of the project each month, you can purchase the subscription multiple times. (That is, we'll no longer have three-a-month or ten-a-month subscription options.) This subscription can be purchased on a three-month basis, as before, or a new yearly billing basis at a reduced price. These billing terms correspond to three and twelve different projects, respectively, not necessarily to a specific period.

If you're currently on a three- or ten-a-month subscription you'll be automatically moved to a single subscription from the next renewal. You'll then be able to add additional subscriptions as above. An alternative would be to buy additional kits at the shop each month while only having a single subscription.

If you want to move to a yearly billing cycle subscription, change your subscription at your admin console; this change will take effect on your next renewal.

No more 'deals'

I never felt comfortable with 'sign-up' discounts. They inadvertently mean that one values new customers over existing ones, which is exactly the opposite of what I want. Existing members are what makes the Club special and their satisfaction is my focus. My view is that a strong existing community will attract new members organically without gimmicks and monetary incentives. I will therefore not offer any future sign-up discounts and everyone will pay the same for their membership. I will instead invest in increasing the value of the Club to members.

Deals for students and academics

That lasted long! :)

This 'deal' is the exception. I'm convinced that an option that's more affordable to students makes a lot of sense. I've long struggled with how to make this viable while keeping admin costs low. (Verifying that someone is a student over a long period of time is not a trivial task.)

For a discounted membership a student will need to ask a faculty member to contact us for a unique discount code that can be used multiple times. The faculty will then distribute this code to students or use it themselves for teaching, or getting students excited about electronics. The delivery address for each unique code must be the same university address so that all projects can be shipped together.

The codes will be for a 20% discount and apply for a total of twelve projects. After that the process will need to repeat, or the subscription will go to the normal price. There will be a more detailed set of instructions for this programme in the coming weeks.

Assumed equipment and materials

Many subscription boxes assume that you have basic materials. Our HelloFresh food boxes, for example, assume that we have salt, pepper, oil, and basic cooking equipment. For the Club we'll also assume that people have the basics: a soldering iron, solder wire, small wire-cutter, wire, fine tweezers, a microcontroller-based board for driving some projects, and a USB-to-serial cable for serial programming microcontrollers.

Not all of the above will be necessary for all projects, but these are the essentials for hardware work. We'll have a more complete list ready soon.

These changes will roll out in the next couple of weeks together with a refreshed website. I'm excited about the coming year and about the things that I'm planning on sending your way and I hope that you are too!

All the best,

Be part of a Boldport project

Saar Drimer

I've been asked by a gallery in Dublin to design a very large (180x60cm!) circuit board. That is, it needs to look like an 'ordinary' circuit board, just very very large. It will be single sided and will not be functional. We've gone through the preliminaries and have found a manufacturer to work with on making it for us. Now I just need to design the thing! :)

My plan is to stitch together many designs from many sources using PCBmodE. Here's where you may come in. If you have large designs that you can share and that I could freely use, please send them to me.

Whoa. Not so fast. I can't handle all of the formats out there!

Here's the best way to send the designs to me. For each copper, soldermask and silkscreen layer, convert to SVG or PDF using your EDA tool (most should be able to convert to PDF). Black content on white background is best. Label each with 'top', 'bottom', and 'internal-n', where 'n' is the layer number, corresponding to their position.

Send them to with the following statement:

I am the owner of the attached work and I authorise its use by Boldport for any purpose. I accept that I will not be able to revoke this authorisation once it is given.


In exchange for your help, work, and kindness, we will do our best to include your name as contributor next to the piece when it is displayed and on the work's on-line page.


About the Boldport Club's future

Saar Drimer

Update: here are the changes.

Dear Boldport Club members and friends,

Boldport Club is a success. When I started advertising this concept in January 2016 I expected a 100 people to sign up within six months. 170 people joined before I made the first shipment in March. We're now 370 active members and steadily growing by out-pacing the churn.

We have cultivated a very strong community thanks to your participation. I'm delighted that the Club has attracted such interesting and engaging people from all backgrounds and expertise levels; it is rewarding to follow the wide range of topics discussed on Slack and know that those were facilitated through a common appreciation of what the Club offers.

I'm about to ship the tenth project to you. We will then have shipped over 3000 packages in ten months. This fast pace ─ concept, research, design, prototype, production, shipping ─ is the good kind of challenge and I'm happy that we have been able to (mostly) meet our goals. I've been reviewing the answers to our recent questionnaire and learning a lot from them; it's clear that most of you are very happy with what you've been getting out of the Club.

For the first few projects I've had previous work to build on while the more recent projects were completely new. I currently have the prototypes for Project #11 working on my desk, and Project #12's design is almost done. With each project, however, the time margins have been shrinking. What this means in practice is that I'm not spending as much time with each project as I think is necessary to achieve the result I’d like to ship to you. Things have become a bit too rushed. The creative element of the designs I create cannot be crammed into an all-nighter; this sort of work requires 'rest' and time to mature in order to be effective. Recently, I've also noticed that I've not had enough time for important things other than project creation and shipping: project-build content, website revamp, and engaging with our community.

So, all of this to say that there will be a two month pause in deliveries after Project #10. The next project after that will be shipped mid-March 2017. I'm not taking a break. I'll be dedicating some more time to attending to the operational side of running the Club: recruitment, supplier relationships and engagement, assembly and shipping improvements, and dealing with growth. Basically, the things that would make the operation get into a sustainable pace. I will apply all that I’ve learned this past year and consider the changing financial environment. I will, of course, continue to create kits that will be sent to you when deliveries resume.

The general format will not change. It's obviously working. But I’m now considering more subscription options (like a 'pro' as in 'prototype') and lengths (subscribe for a year at a discount), bigger projects that members can buy at the shop, and ways to engage with the community better. I’m going to re-evaluate subscription costs that can accommodate different members ─ such as students ─ better.

There's nothing you need to do at this point. I'll sort out your accounts so that you only pay for what you get. If you decide to cancel the subscription during this time and would like a refund for the kits you've paid for that are delayed, just email me. I do hope, however, that you'll stay with us. New members will still be able to sign up during this ‘shipping pause’ period.

Our community on Slack will remain as active as usual and you're welcome to discuss this message on the #meta channel. If you'd like to collaborate on a project or have some ideas, now would be a good time to get in touch and start making plans. Also, if you’d like to collaborate on, or contribute to, some aspects of the Club ─ newsletter, curation of member-generated content, graphics and design, etc. ─ I’d love to hear from you.

I’m grateful to you all for making Boldport Club what it is. I’ve been working full-time on the concept of ‘beautiful and functional’ circuits for several years now, and only with the success of the Club I can be finally confident that I will be able to continue doing this work for a living, work that I thoroughly enjoy. Thanks for that.

All the best,


Component side, solder side

Saar Drimer

The first board with the solder polarity symbol

Anyone who's soldered even (or especially!) for a short while will recall the sinking feeling of soldering a component on the wrong side of the board. It's usually not a disaster, but it is annoying to have to deal with the re-work when you're excited with getting on with building the thing to completion.

Several people soldered the components on the wrong side while assembling this board

For stylistic reasons, Boldport Club Project #1, the Pease, confusingly had the component symbols on the back of the board, while the components actually needed to be soldered from the top side. Even though pin-1 markings for the IC (the most crucial component in this context) were there to avoid the ambiguity, many — particularly experienced engineers who make assumptions based on prior experience — soldered the components on the wrong side.

This is a design — not a user — issue that needs addressing. While there's only so far a designer can go in order to prevent users from making mistakes, helping them with effective but unobtrusive cues greatly helps attain a better overall experience. This is a primary goal in my work.

I thought for a while how to elegantly convey the soldering 'polarity', as I did not want to do the obvious: explicitly writing 'solder side' and 'component side'.  It's ugly, and takes away attention from other, more important, visual features on the board.

I thought that a symbol could work well and here's what I came up with

and it is first used on the TAP board, an upcoming Boldport Club project.

Symbol on the component side

Symbol on the solder side

Symbol on the solder side

The problem with new symbols is that those who are meant to pay attention to them need to know what they're looking at, or for. For that, there's this blog post, and I do intend on including a little note to draw the attention of future project recipients.

The symbol files are at our GitHub repo and are licensed under the Creative Commons Zero.

Boldport Club Project #2 — the tiny 'engineer superhero' emergency kit, second edition

Saar Drimer

This started it all, a PCB business card.

It all started when in search for a unique design twist almost three years ago I experimented with embedding through-hole components inside of the PCB itself. Researching this, I found that other than the slots that sometimes cost extra, there's nothing preventing me from achieving this with a standard manufacturing process. I then made the "engineer's emergency business card", which got a very positive response [Hackaday | HackerNews].

The first edition kit

The first edition kit

This response led me to create my first ever kit, "the tiny 'engineer superhero' emergency kit, first edition", spiced up with a tale of where an engineer might use it

It's meant to be an engineer's emergency kit. When all hope is lost, the MacGuyver engineer could snap out one of the components and save the day. Recall the countless times you desperately needed a 1 KOhm resistor to fix an amplifier at a party, only to see the person you were trying to impress slip away with an OCaml programmer? Never again with this little kit.


It's a functional circuit. When you apply voltage the LED turns on, and the solder wire bit is part of this circuit.

Another new 'thing' was gently laser etching a compressed cellulose sponge so that when wet expands to fit the tin the kit arrives in and can be used to clean a soldering iron as one is soldering.

This kit is special because — other than the in-circuit components, visuals, and sponge — it's the kit through which I learned a lot about kitting and selling kits. I felt that it would be great to send members of the Boldport Club the second edition of this kit, and in this way share this first experience that eventually led me to start the Club.

This 'second edition' comes in a black tin can and has new two-tone visuals. Next week I'll be sending these kits to Club members, and all of those who joined the Club by the cut-off date of April 9th will receive a second one as a gift for their support! Sign up here.

The second edition has a two-tone visuals, using soldermask at places.

The sponges for this kit were supplied by our friends at Oomlout — who are also enthusiastic members and supporters of the Boldport Club. The PCBs were manufactured by Eurocircuits. And, as usual, the design is open source hardware, and is available at our GitHub repository. A full album of the kit is here.

Could this little kit save your career?!

Boldport Club project #1 — make sure one is yours!

Saar Drimer

The Boldport Club — a monthly subscription to electronics projects — has been very well received. We now have over 85 members, even before we shipped our first project! We're getting ready for delivering our first project to members: a tribute to Bob Pease and an electronics discovery kit based on his LM331 chip.

An engineer and an artist?!

The famous quote from Robert Allen Pease

Bob Pease was an analogue design expert and technical writer of legendary status. He had the unique ability to communicate very technical topics in a relatable style, character, and authority, and thus becoming an educator to generations of engineers. One of Pease's most memorable sayings was 'My favorite programming language is... solder', which captures so much of our love for electronics and creating things with our minds and hands.

The original 'Pease'. I made only50 and mostly given them away...

A couple of years ago, I designed a tribute to Pease, which was one of the first boards that I've created with PCBmodE. I've not sold the board widely — I only made 50 and most of them I gave away — but it was always a board that got attention. When I considered which of my designs should be the first to be sent to Boldport Club members, it had to be this one.

Now updated to a 'second edition', the board is based around Pease's LM331, a voltage to frequency converter chip. The circuit on the board is a light intensity to frequency converter, exactly as shown in Figure 20 of the datasheet. (There's an extra bit for flashing an LED with the output.)

The schematic for the circuit is drawn on the back of the board for easy reference, and either through-hole or surface-mount components can be used (the kit only contains through-hole components, though).


The contents of the kit. Each kit comes with two instances of the PCB.

It's a 'discovery kit' since you should figure out how to tweak the values of the components to do different things. You may need to use different components, and you're likely want to consult the datasheet for how the chip works. Maybe even connect it to a scope! Power can be applied through the USB connector or through the holes on the other side. There's even a handy ruler, and a keyring if you want to carry the board with you.

As usual, this board is open source hardware, and the design files for both the PCB and package are here. The full album for this kit is here. And here's a video of the board in operation

So here's the deal: we're shipping this project to members of the Boldport Club at the beginning of March. If you're not a member by then you won't get this project, as we don't repeat projects or send new members old projects (members can still buy old stock while it lasts, though). We're building a limited amount of this special project, so we suggest that you hurry :)

News from the Boldport front

Saar Drimer

A quick update.

Boldport Club accepts memberships


After a few months of planning, we've opened the Boldport Club for people to join as members. For £49 you'll get three projects of our making; you know, the good stuff that we've been making for a while. We're very excited about the potential of the Club, and we hope that you'll join us, along with your friends and relatives ;)

New website

Towards the end of November we released a new version of our website at We've got a new logo, and a better message. Please explore the website, and send anyone who could use 'electronics craftsmanship' our way.

PCBmodE version 4.0

PCBmodE is our own (open source software) circuit design tool with which we design all of our boards. Over the past few months we've implemented new features — most notably, support for multiple layers — and improved usability. Several boards at the repository are compatible with the new version and are a great place to start with the software.

FOSDEM presentations

FOSDEM (Free and Open Source Software Developers' European Meeting) is a large, free, gathering for open source software developers, happening next weekend in Brussels. I'll be speaking at the eda-devroom twice; once about PCBmodE and another about the future of EDA. If you'll be at FOSDEM, make sure to let me know and we'll arrange to meet.

Finally, the office move

Our place off of Borough High Street was great, but we needed more space. After a few weeks of searching, I've found what I think will be a great place to work from. It's at the Arch Collective, along-side a laser-cutting and model-making businesses. We're moving in tomorrow, and I'm looking forward to working at the new space. Feel free to come by and say hello!


Haute circuits

Saar Drimer

This one didn't make it to the printed magazine. Credit: Marie Claire, Mitch Feinberg

It was a privilege and a pleasure to work with Mitch Feinberg, an accomplished still-life photographer with a long record of amazing work. Marie Claire US magazine commissioned photographs of luxury jewellery — Tiffany, Chopard, Bulgari, Cartier, Yurman, and Harry Winston — from Mitch.

Mitch conceived the idea of having large bespoke circuitboard designs as the backdrop for the jewellery, and a Web search led him to Boldport and me. It was serendipitous; the old Boldport website was not explicit about us doing this kind of work, but Mitch was acute at sensing that this is the exact kind of work I wanted to attract! Our custom tool, PCBmodE, allows us to achieve the visuals and designs like no other tool can, and we were just the right company for the job.

The work appears in the December 2015 issue of Marie Claire US

The six photographs below are the ones taken by Mitch and belong to himself and Marie Claire magazine. They cannot be used without their permission. Unfortunately, the Bulgari piece — my personal favourite! — did not make it to print.

Cartier. Credit: Marie Claire, Mitch Feinberg

Yurman. Credit: Marie Claire, Mitch Feinberg

Chopard. Credit: Marie Claire, Mitch Feinberg

Tiffany. Credit: Marie Claire, Mitch Feinberg

Bulgari. Credit: Marie Claire, Mitch Feinberg

Harry Winston. Credit: Marie Claire, Mitch Feinberg

Harry Winston. Credit: Marie Claire, Mitch Feinberg

Below are photographs that I took of the boards and of the magazine. Please ask for permission before use elsewhere. A full gallery of images is here.

The circuitboard designs were inspired by the jewellery piece that would be placed on them. It was an enjoyable creative process. Finally, some of the boards have LEDs. These are SMD LEDs that poke through a hole in the board. Their intensity is controlled by a potentiometer and power is supplied via a microUSB port.

And finally, my credit! :)

EDIT: A couple of my prototype sketches

Let's talk about '3D printed' circuit boards

Saar Drimer

If you haven't yet used a consumer-grade desktop '3D printer' you might still be under the illusion that they are going to 'change the world' as the hype used to promise. Someone once remarked to me about the dynamics of a hackerspace, "they come for the 3D printer but stay for the laser cutter". I certainly did, after fighting with the 3D printer that produced inconsistent, and poor, results, no matter how much effort I put into it. The next time I wanted the wonder of 3D printers I designed a model with OpenSCAD and sent it off to Shapeways and got my item in three different materials a week later. I saved a ton of faffing time, and money, that way. Then, if I wanted twenty, they would be the same quality and shape, and someone will be there to answer if they are not.

So on the heels of that hype arrived a slew of '3D' desktop circuit boards printers — Voxel8, Argentum, and Voltera to name some — which promise the same but for circuitry. The advantages, they say, are faster iteration of prototypes, extended material possibilities, and mechanical construction that isn't otherwise available.

It's easy and natural to get excited about these prospects. But there is only one case I can think of that a consumer-grade '3D' circuit printer justifies its cost: a hackerspace. Other than there, these machines are near useless.

How does a circuit bring-up work? We research the technologies and ICs that we may use. We'll read the datasheets and order evaluation and development kits to play with. If the circuit is simple we'll wire it up with a breadboard, cables, or an Arduino. There's no need for a custom circuit board at this stage. If the circuit is more complex, we'll need a board that can meet our needs -- this may be a 2-or-more-layer board with plated vias or a controlled impedance board with 0.5mm pitch devices. Crucially — and this is what those who promote these devices fail to mention — we want the prototype boards to be the same technology that your production unit. Otherwise, we may be doubling our work and spend more money.

"But you'll have to wait a week for the board to arrive!" It's called 'planning'. If an engineer cannot plan their project to fill their time between sending the boards out and waiting for them to arrive, then something's already wrong. There is so much more to do in a project to fill that time up. Save the two grand you'll spend on a printer you'd use twice for a 'quick-turn emergency fund'. Besides, PCB manufacturers are not sitting idle in the face of demand for quicker turns; most offer a day turn, and that should be good enough for prototypes in a bind. Or, find a local PCB manufacturer and save yourself some shipping time and money.

As for materials, I personally have worked with 'exotic' circuit materials that are production ready and well characterised. Even if I could produce novelty items with one of those printers that would look good on Twitter, how would I scale? How would I make them robust? I couldn't unless I re-do it with a different technology and have to go through a new learning process. As for new 'paradigm changing' constructions, I still haven't seen an example for this that isn't contrived. 

In conclusion I'll say that these consumer-grade desktop circuit printers could have a loving home at hackerspaces for educational and fun one-off projects. But please don't buy into the hype that they are all that useful elsewhere.