Editors’ Pick: Adafruit’s Limor Fried on the DIY Electronics Revolution

The proliferation of open-source hardware and software has made do-it-yourself electronics accessible to both professional electrical engineers and newbies. Today we’re just at the start of an exciting DIY revolution that promises innovation, adventure, and new social, creative, and business opportunities. How will you get involved? In this essay, Adafruit founder Limor Fried offers her thoughts on the present and future of open-source technology.

I’m an MIT-trained electrical engineer and founder of Adafruit Industries, an open-source hardware (OSH) company in New York City. Normally, I tell people that we design and manufacture electronic gadgets—mostly kits and parts for students who are learning to become engineers—or project packs for people who didn’t realize that they wanted to get into electronics. But really what we do is teach, and we do that by creating OSH. Every design we make is fully documented and given away for free—to anyone, for any purpose. But we also sell completely assembled designs as products. Most people just buy from the Adafruit store or from one of our many distributors, but there are still thousands who look at what we create as points of origin for their own businesses or products.

Another way to put it: we’re basically like a test kitchen with a restaurant attached to it. We come up with new dishes, write the recipes up for others to follow at home (or in their own restaurants), and also serve up the dishes to those who don’t have all the equipment and ingredients—they just want to chow down. Other aspiring chefs look at our videos and recipes and adapt them for their own kitchens all over the world. And, once in a while, those same cooks turn around and give away one of their techniques or recipes to the community. Not everyone gives back, but that’s OK. Enough people contribute to create a vibrant culture of sharing.cloud

The best part about talking about OSH is how easy it is. So much has happened with OSH in the last few years that it’s not like I need to sell a pipe dream. It’s not some “experimental future” or “speculative fiction” about what could occur. OSH is already happening, so all I have to do to predict its future is to accurately describe what’s going on right now. But first, a brief introduction.

Open-Source 101

Nearly everyone knows about open-source software (OSS). Sure, you may not be a coder, but you’ve used the Internet, which is pretty much fully made of OSS: websites running the ubiquitous Apache webserver software, displaying customized sites written in Ruby or PHP, drawing on pools of data stored in MySQL databases all running on server computers running the open-source Linux operating system.

The fantastic thing about all this free OSS is how it has helped proliferate the Internet, improving the functionality of the web through rapid mutations in code (that’s the free-as-in-speech part) and driving down the cost to commodity levels (that’s the free-as-in-beer part). The commodification of the Internet—that is, the marginal cost of an blog or email account is so low that it’s essentially free—and indeed nearly all computer software and hardware would not be possible without OSS.

OK, so that’s the state of the Internet as of circa 1995. Although the details have evolved, the essence of OSS is the same. But something interesting started happening a few years ago in the hardware world (i.e., atoms instead of bits): stuff started getting both complex and cheap. Suddenly, everything had a microcomputer inside of it, and if you had a microcomputer, you needed data to crunch. The market for sensors—what would normally be shoved into extremely expensive military hardware—started ballooning. (When I was in college, a triple-axis accelerometer motion sensor would cost $60. Now it costs less than $1.) Once low-cost sensors and easily reprogrammable logic chips started flooding the market, online communities of engineering geeks started to take notice. Engineers start using what they had learned at work to build hobby projects. The parts were finally cheap enough. And as a result, they started laying down the groundwork: compilers, simulators, and toolchains. That was the mid-1990s. Soon thereafter, geek artists started taking a look and liked what they saw. They started designing interactive art, building on some of the great electronic art concepts of the 1970s. And finally, non-geeks had a crack at it. Complex electronics and electrical engineering went from something requiring years of differential equations to weekend fun.

While all this was happening, something cool began occurring. Just as code geeks created OSS to help commodify the Internet, solder geeks decided to apply the same principles to the creation of hardware (both mechanical and electronic). They started sharing schematics, CAD files, and layouts on social websites. Today, designers use a variety of sites (e.g., Instructables.com, Thingiverse.com, and LetsMakeRobots.com) and via various social services (e.g., Flickr, Twitter, Facebook, and Google+) to give away inventions and post tutorials and instructions for free.

The Proliferation of OSH

The first response we can have is this: OK. Free and OSS erased the costs of software while also increasing demand (and thus lowering the price) for desktop computers. Then followed laptops (say, OLPC, which runs exclusively OSS) and finally cell phones (e.g., Android). So, we’ll also see OSH reduce costs and simultaneously speed up iterations of new and better devices by separating the IP control (say, patents) from the ability to manufacture.

There’s also another response we can take to the proliferation of OSH. Not only is it making it easier than ever to design and manufacture original products to fit a group’s needs, it’s also providing a broad curriculum to the world. Someone who has the desire to learn how to build and repair electronics will not learn much by taking apart a modern cell phone—everything is too small, poorly documented, and hidden. But with OSH, documentation is an essential part of the process—describing why a certain component is chosen and possible alternatives gives insight. The student is empowered to trace the design from thought-process to mathematical analysis to specifications to fabrication.

OSH Projects

Let’s consider some examples of what is happening in OSH right now. First of all, I’m sure you’ve already heard about 3-D printing from MakerBot. It used to be a technology only available to high-end prototyping houses that could spend the tens of thousands of dollars on both machinery and upkeep. But then about five years ago, a few different groups such as Fab@Home and RepRap decided they wanted create low-cost home versions as well as make the projects OSH. So they gave away all the plans with the hopes that others would build, improve, and proliferate the basic plan of low-cost 3-D printing. Now there are over 100 low-cost 3-D printer design variations available for anyone to make. In addition, a massive community is constantly improving the quality, lowering the price, and simplifying things. It’s possible that within a few years we could see 3-D printers that cost $100 and are built of common hardware store parts.

Another example that has promise is the Global Village Construction Set, which is a “manual” of simple, easy-to-repair construction equipment. Instead of high-cost specialized tools from John Deere or Caterpillar, each of a dozen machines can be fabricated using basic steel welding, electrical wiring, and some basic common components. The hope is not that it would replace the many powered tools already available, but that it would enable people to approach the design of new tools without fear that they had nowhere to start from. That is to say, by being broad and simple, it can encourage specialization when needed, whereas most equipment manufacturers would not be interested in selling something unless they had tens of thousands of customers.

Finally, one of my favorite projects is the Dili Village Telco project. There are no phone lines in the East Timor village. There is a cell network, but it’s expensive and not very useful for making calls within the village. David Rowe, a telephony engineer, designed a sort of “micro cell” so that the Timorese in the village could use regular phones to call each other, basically like a little version of AT&T. Rowe designed the very complex hardware, which not only has to work but also has to work well in the difficult environment of a village without cables or consistent power. What I thought was most interesting about the project is how he was giving  away the years’ worth of work, posting up schematics, DSP code, filters, and more with the hope that some company would come by and rip him off. The best thing that could happen for the project is to have the design mass manufactured because then he could get on with the work of deploying and configuring the network boxes instead of figuring out how to get them made.

The Speed & Power of OSH

Now I’ll share personal example of the speed and power of open-source hardware and software. About a year ago, I was mucking about with trying to design a low-cost, high-efficiency solar battery charger. Solar panels are really annoying to deal with, and although there are lots of off-the-shelf solutions for big solar panels—say, over 50 W—there isn’t a lot available for 5 W or under. I ended up designing what I thought was a pretty clever battery charger that used off-the-shelf parts and then began selling it in the Adafruit store. A few months later, I got an e-mail from a fellow who had designed a solar-powered cell phone charger and liked the design and efficiency. He had a Kickstarter going to sell them, and just wanted me to know that he had taken the design and remixed it. Some people would consider such a scenario a nightmare: I spent months in the sun tweaking the design and some guy just rips it off to make money. But I thought it was great. In fact, nothing would make me happier than to hear that every design I’ve worked on and published was used to create a useful product.

Share Knowledge, Share Success

So, on to the future! One thing that makes me most excited is the proliferation of low-cost cell phones that are easy to program (Android in particular). Once you take a programmable cell phone and connect ultra-low-cost sensors, you’ve got a global sensor network—a very powerful tool that enables anyone to measure and monitor the environment.

More sensors, more things talking. You’ll hear about the “Internet of Things” a lot more in the future. A lot of OSH makers cross-pollinate from hobbyist projects to manufacturer products to other industries. For instance, you’ll see medical devices get smarter. Quickly being able to pull from a library of open-source projects and make a Kickstarter or some other crowd-funded service will lower the entry barrier for many engineers and makers. Sure, there are challenges once you actually get the funding, but it’s never been a better time to work on OSH and get your designs out there. Previously, capital needed to be raised via venture capitalists, loans, or friends and family.

What I like about the future of electronics—and DIY electronics in particular—is that it’s more than just about the physical bits. The OSH movement has a built-in cause: sharing knowledge. If we can all provide a little more value when we make something, we can develop more things by standing on each other’s shoulders and make more engineers who share the same values.

FriedLimor Fried founded Adafruit Industries in 2005. She earned a Bachelor’s in EECS and a Master’s of Engineering from MIT This essay first appeared in CC25 (2011).

Self-Reconfiguring Robotic Systems & M-Blocks

Self-reconfiguring robots are no longer science fiction. Researchers at MIT are rapidly innovating shape-shifting robotic systems. In the August 2014 issue of Circuit Cellar, MIT researcher Kyle Gilpin presents M-Blocks, which are 50-mm cubic modules capable of controlled self-reconfiguration.

The creation of autonomous machines capable of shape-shifting has been a long-running dream of scientists and engineers. Our enthusiasm for these self-reconfiguring robots is fueled by fantastic science fiction blockbusters, but it stems from the potential that self-reconfiguring robots have to revolutionize our interactions with the world around us.

Source: Kyle Gilpin

Source: Kyle Gilpin

Imagine the convenience of a universal toolkit that can produce even the most specialized tool on demand in a matter of minutes. Alternatively, consider a piece of furniture, or an entire room, that could change its configuration to suit the personal preferences of its occupant. Assembly lines could automatically adapt to new products, and construction scaffolding could build itself while workers sleep. At MIT’s Distributed Robotics Lab, we are working to make these dreams into reality through the development of the M-Blocks.

The M-Blocks are a set of 50-mm cubic modules capable of controlled self-reconfiguration. Each M-Block is an autonomous robot that can not only move independently, but can also magnetically bond with other M-Blocks to form larger reconfigurable systems. When part of a group, each module can climb over and around its neighbors. Our goal is that a set of M-Blocks, dispersed randomly across the ground, could locate one another and then independently move to coalesce into a macro-scale object, like a chair. The modules could then reconfigure themselves into a sphere and collectively roll to a new location. If, in the process, the collective encounters an obstacle (e.g., a set of stairs to be ascended), the sphere could morph into an amorphous collection in which the modules climb over one another to surmount the obstacle.  Once they have reached their final destination, the modules could reassemble into a different object, like a desk.

The M-Blocks move and reconfigure by pivoting about their edges using an inertial actuator. The energy for this actuation comes from a 20,000-RPM flywheel contained within each module. Once the motor speed has stabilized, a servomotor-driven, self-tightening band brake decelerates the flywheel to a complete stop in 15 ms. All of the momentum that had been accumulated in the flywheel is transferred to the frame of the M-Block. Consequently, the module rolls forward from one face to the next, or if the flywheel velocity is high enough, it rapidly shoots across the ground or even jumps several body lengths through the air. (Refer to www.youtube.com/watch?v=mOqjFa4RskA  to watch the cubes move.)

While the M-Blocks are capable of independent movement, their true potential is only realized when many modules operate as a group. Permanent magnets on the outside of each M-Block serve as un-gendered connectors. In particular, each of the 12 edges holds two cylindrical magnets that are captive, but free to rotate, in a semi-enclosing cage. These magnets are polarized through their radii, not through their long axes, so as they rotate, they can present either magnetic pole. The benefit of this arrangement is that as two modules are brought together, the magnets will automatically rotate to attract. Furthermore, as one and then two additional M-Blocks are added to form a 2 × 2 grid, the magnets will always rotate to realign and accommodate the additional modules.

The same cylindrical magnets that bond neighboring M-Blocks together form excellent pivot axes, about which the modules may roll over and around one another. We have shown that the modules can climb vertically over other modules, move horizontally while cantilevered from one side, traverse while suspended from above, and even jump over gaps. The permanent magnet connectors are completely passive, requiring no control and no planning. Because all of the active components of an M-Block are housed internally, the modules could be hermetically sealed, allowing them to operate in extreme environment where other robotic systems may fail.

While we have made significant progress, many exciting challenges remain. In the current generation of modules, there is only a single flywheel, and it is fixed to the module’s frame, so the modules can only move in one direction along a straight line. We are close to publishing a new design that enables the M-Blocks to move in three dimensions, makes the system more robust, and ensures that the modules’ movements are highly repeatable. We also hope to build new varieties of modules that contain cameras, grippers, and other specialized, task-specific tools. Finally, we are developing algorithms that will allow for the coordinated control of large ensembles of hundreds or thousands of modules. With this continued development, we are optimistic that the M-Blocks will be able to solve a variety of practical challenges that are, as of yet, largely untouched by robotics.

Kyle Gilpin

Kyle Gilpin


Kyle Gilpin, PhD, is a Postdoctoral Associate in the Distributed Robotics Lab at the Massachusetts Institute of Technology (MIT) where he is collaborating with Professor Daniela Rus and John Romanishin to develop the M-Blocks. Kyle works to improve communication and control in large distributed robotic systems. Before earning his PhD, Kyle spent two years working as a senior electrical engineer at a biomedical device start-up. In addition to working for MIT, he owns a contract design and consulting business, Crosscut Prototypes. His past projects include developing cellular and Wi-Fi devices, real-time image processing systems, reconfigurable sensor nodes, robots with compliant SMA actuators, integrated production test systems, and ultra-low-power sensors.

Circuit Cellar 289 (August 2014) is now available.

The Future of Small Radar Technology

Directing the limited resources of Fighter Command to intercept a fleet of Luftwaffe bombers en route to London or accurately engaging the Imperial Navy at 18,000 yards in the dead of night. This was our grandfather’s radar, the technology that evened the odds in World War II.

This is the combat information center aboard a World War II destroyer with two radar displays.

This is the combat information center aboard a World War II destroyer with two radar displays.

Today there is an insatiable demand for short-range sensors (i.e., small radar technology)—from autonomous vehicles to gaming consoles and consumer devices. State-of-the-art sensors that can provide full 3-D mapping of a small-target scenes include laser radar and time-of-flight (ToF) cameras. Less expensive and less accurate acoustic and infrared devices sense proximity and coarse angle of arrival. The one sensor often overlooked by the both the DIY and professional designer is radar.

However, some are beginning to apply small radar technology to solve the world’s problems. Here are specific examples:

Autonomous vehicles: In 2007, the General Motors and Carnegie Mellon University Tartan Racing team won the Defense Advanced Research Projects Agency (DARPA) Urban Challenge, where autonomous vehicles had to drive through a city in the shortest possible time period. Numerous small radar devices aided in their real-time decision making. Small radar devices will be a key enabling technology for autonomous vehicles—from self-driving automobiles to unmanned aerial drones.

Consumer products: Recently, Massachusetts Institute of Technology (MIT) researchers developed a radar sensor for gaming systems, shown to be capable of detecting gestures and other complex movements inside a room and through interior walls. Expect small radar devices to play a key role in enabling user interface on gaming consoles to smartphones.

The Internet of Things (IoT): Fybr is a technology company that uses small radar sensors to detect the presence of parked automobiles, creating the most accurate parking detection system in the world for smart cities to manage parking and traffic congestion in real time. Small radar sensors will enable the IoT by providing accurate intelligence to data aggregators.

Automotive: Small radar devices are found in mid- to high-priced automobiles in automated cruise control, blind-spot detection, and parking aids. Small radar devices will soon play a key role in automatic braking, obstacle-avoidance systems, and eventually self-driving automobiles, greatly increasing passenger safety.

Through-Wall Imaging: Advances in small radar have numerous possible military applications, including recent MIT work on through-wall imaging of human targets through solid concrete walls. Expect more military uses of small radar technology.

What is taking so long? A tremendous knowledge gap exists between writing the application and emitting, then detecting, scattered microwave fields and understanding the result. Radar was originally developed by physicists who had a deep understanding of electromagnetics and were interested in the theory of microwave propagation and scattering. They created everything from scratch, from antennas to specialized vacuum tubes.

Microwave tube development, for example, required a working knowledge of particle physics. Due to this legacy, radar textbooks are often intensely theoretical. Furthermore, microwave components were very expensive—handmade and gold-plated. Radar was primarily developed by governments and the military, which made high-dollar investments for national security.

Small radar devices such as the RFBeam Microwave K-LC1a radio transceiver cost less than $10 when purchased in quantity.

Small radar devices such as the RFBeam Microwave K-LC1a radio transceiver cost less than $10 when purchased in quantity.

It’s time we make radar a viable option for DIY projects and consumer devices by developing low-cost, easy-to-use, capable technology and bridging the knowledge gap!
Today you can buy small radar sensors for less than $10. Couple this with learning practical radar processing methods, and you can solve a critical sensing problem for your project.

Learn by doing. I created the MIT short-course “Build a Small Radar Sensor,” where students learn about radar by building a device from scratch. Those interested can take the online course for free through MIT Opencourseware or enroll in the five-day MIT Professional Education course.

Dive deeper. My soon-to-be published multimedia book, Small and Short-Range Radar Systems, explains the principles and building of numerous small radar devices and then demonstrates them so readers at all levels can create their own radar devices or learn how to use data from off-the-shelf radar sensors.

This is just the beginning. Soon small radar sensors will be everywhere.

MIT’s Self-Assembling Robots

Calling it a low-tech solution to a high-tech challenge, MIT researchers have received a lot of attention recently for their modular system of self-assembling robot cubes. The video of the so-called M-Blocks in action, which MIT posted earlier this month on YouTube, has also become high profile. A recent tally has the video at nearly 1.5 million views and counting.


The text accompanying the video explains how the cubes are able to move around and climb over each other,  jump into the air, and roll across surfaces as they connect in a variety of configurations. And they do all this without any external moving parts. Instead, each M-Block contains a flywheel that can reach speeds of 20,000 rpm. When the flywheel brakes, it imparts angular momentum to the cube.  Precisely placed magnets on every face and edge of each M-Block enable any two cubes to attach to each other.

The simple design holds short- and long-term promise.  According  to an October 4 article by Larry Hardesty of the MIT News Office, it is hoped that the blocks can be miniaturized someday, perhaps to swarming microbots that can self-assemble with a purpose. Even at their current size, further development of the M-Blocks might lead to “armies of mobile cubes” that can help repair bridges and buildings in emergencies, raise scaffolding, reconfigure into heavy equipment or furniture as needed, or head in to environments hostile to humans to diagnose and repair problems, the article suggests.

While it may not rise to “cooperative group behavior,”  the ability of one cube to drag another and influence its alignment is impressive. What could 100 or more of these robots accomplish as MIT researchers continue to develop algorithms to control them?

A prototype of the new modular robot, with its flywheel exposed. (Photo: M. Scott Brauer)

A prototype of the new modular robot, with its interior and flywheel exposed.
(Photo: M. Scott Brauer)

Embedded Sensor Innovation at MIT

During his June 5 keynote address at they 2013 Sensors Expo in Chicago, Joseph Paradiso presented details about some of the innovative embedded sensor-related projects at the MIT Media Lab, where he is the  Director of the Responsive Environments Group. The projects he described ranged from innovative ubiquitous computing installations for monitoring building utilities to a small sensor network that transmits real-time data from a peat bog in rural Massachusetts. Below I detail a few of the projects Paradiso covered in his speech.


Managed by the Responsive Enviroments group, the DoppelLab is a virtual environment that uses Unity 3D to present real-time data from numerous sensors in MIT Media Lab complex.

The MIT Responsive Environments Group’s DoppleLab

Paradiso explained that the system gathers real-time information and presents it via an interactive browser. Users can monitor room temperature, humidity data, RFID badge movement, and even someone’s Tweets has he moves throughout the complex.

Living Observatory

Paradiso demoed the Living Observatory project, which comprises numerous sensor nodes installed in a peat bog near Plymouth, MA. In addition to transmitting audio from the bog, the installation also logs data such as temperature, humidity, light, barometric pressure, and radio signal strength. The data logs are posted on the project site, where you can also listen to the audio transmission.

The Living Observatory (Source: http://tidmarsh.media.mit.edu/)


The GesturesEverywhere project provides a real-time data stream about human activity levels within the MIT Media Lab. It provides the following data and more:

  • Activity Level: you can see the Media Labs activity level over a seven-day period.
  • Presence Data: you can see the location of ID tags as people move in the building

The following video is a tracking demo posted on the project site.

The aforementioned projects are just a few of the many cutting-edge developments at the MIT Media Lab. Paradiso said the projects show how far ubiquitous computing technology has come. And they provide a glimpse into the future. For instance, these technologies lend themselves to a variety of building-, environment-, and comfort-related applications.

“In the early days of ubiquitous computing, it was all healthcare,” Paradiso said. “The next frontier is obviously energy.”