Behind The Scenes of Modulo*

Photo taken by OSH Park's Kelly during Bay Area Maker Faire 2015.
Co-written with Erin Tomson

I met Erin Tomson at her lovely purple Maker Faire booth shortly after the kickstarter launch for Modulo, a set of tiny modular circuit boards that enables you to create custom electronics projects without the hassle of designing and assembling circuits from scratch!

Photo taken by OSH Park's Kelly during Bay Area Maker Faire 2015.

The inspiration for Modulo was a direct result of Erin trying to learn about control systems and actively balanced robots, by teaching herself how to make a small two wheeled “segway style” balancing robot.

She had a grasp of the necessary electronics: an IMU (accelerometer/gyro), motor driver, and microcontroller. So, she thought it’d only take a few minutes to connect those components and she’d have her robot. The reality became more an exercise in electronics design than control theory and robotics. Before she had a working robot, she found herself devoting a large amount of time to researching and studying datasheets, designing a circuit, and breadboarding it, making mistakes that damaged components, then finally transferring it to a robust soldered proto board.

She determined that this aspect of designing an assembling electronics has lagged far behind the powerful easy to use microcontrollers and single board computers that we have to today, and decided to do something about it. That something is now known as Modulo.

Unfortunately, there’s no magical wand for instantly transforming an idea into a product. However, there are methods that help the process. For example, Erin explained that setting the launch date for the kickstarter campaign, a week and a half before Maker Faire, set the entire schedule for the project. Fortunately, her team was able to stick to that schedule, and we didn’t slip even by a day. I’m sure I’d still be tweaking if I hadn’t drawn that line in the sand. Bringing the project to fruition in time was also guided by the principle: Done is more important than perfect.

While discussing her process, Erin commented that she views Modulo as a software engineering approach to hardware. She has taken successful concepts from the world of programming, such as object oriented design, separation of concerns, and abstraction, and applied them to hardware. This is evident in the way each module is literally a separate object, dealing with one particular function and handling the low level operation, exposing only a high level API.

Erin explains, Modulo has some really interesting features that go far beyond just breaking out pins of a microcontroller. Devices communicate using the well known I2C protocol, but on top of that we’ve added some fantastic new capabilities. Those new capabilities are what make Modulo the perfect hardware/ software combination for someone first learning about making, educators, and established makers too busy to complete all the necessary tasks for what they’d like to be a quick and easy weekend project.


For starters, Modulo devices are discoverable. This means the controller can efficiently find every device that’s connected to the bus, and determine such things as manufacturer, device firmware version, and what capabilities the device supports.

Secondly, the modules support dynamic addressing. Usually with I2C devices, you need to solder address jumpers when using more than one of the same type of device. Even then, you may be limited to just a few. With Modulo, you can connect any number of the same device and the controller will automatically assign I2C slave addresses to them.

Third, the modulo protocol uses error correction, allowing you to use longer cables than would normally be advisable with I2C. If a transmission fails due to electrical noise, the controller will detect that and retransmit.

Finally, one of the best built-in features of Modulo, is it has a higher level serial protocol that makes devices controllable over USB. This means a program running on your computer (perhaps a script or a program with a UI) can use convenient APIs to control the hardware you build.


When describing her favorite and most difficult experiences when breathing life into the project, Erin shared the most difficult obstacle was communicating her vision behind the project to the rest of the world. As an engineer at heart, she’s found sales, marketing, and advertising are not her strongest talents. If I just did what came naturally, I’d probably never tell anyone about Modulo. That doesn’t make for a very good business plan, though. Her background is in developing very large, proprietary software for a huge organization. So as you can imagine, she’s found switching to running a tiny company, doing lean open hardware, a major shift with a steep learning curve. With manufacturing, the challenge is designing for someone else to make thousands of something. And unlike software, she’s confronting the tough realities regarding inventory, supply chain, and volume pricing.

With a lot of help from talented friends, Erin was able to overcome this.They have all done really incredible work and I’m fairly certain the project would have flopped without them. Brandon Smith and Tim McLoone, who run the design/marketing boutique, designed the Modulo logo, website, and materials for Maker Faire. They also helped establish a social media presence on facebook and twitter. Another friend, Jason Kim, lent his filming and editing talents to create the kickstarter video.

The kickstarter ends soon, and more backers are needed to release the amazing Modulo modules currently ready for manufacture but trapped in the land of stretch goals.  Perhaps more importantly, the kickstarter needs to hit stretch goals for Modulo to become a viable company.  Therefore, supporters waiting until after the campaign to buy a module or kit may leave Modulo in a difficult spot.


If you wish to support the campaign, you should go to kickstarter project page at and make a pledge before the campaign closes on Tuesday at 8pm PDT.

Additional credit:

This post contains some content Erin shared from her interview with Rob Reilly. The article written from that interview can be found here.

*Erin and I originally co-wrote this post for the OSH Park blog.


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