Color Commons

I recently heard about Color Commons, an interactive public artwork created by New American Public Art. The idea is to allow the public to change the color of the Boston Greenway Light Blades via text message. You simply send an SMS to the Light Blades number (917.525.2337) that says what color you want the lights to be and within about 1 second, the lights will change.

I think this is an awesome project on several different levels. First is the element of interactivity – I really like art that engages viewers beyond a passive consumption level. I also think that the creativity and diversity of perspective embodied by “the public” can discover and create really interesting usage scenarios that the original artist would never have thought of (perhaps this just betrays a lack of confidence in my own creativity and artistic vision but nevertheless…).

It is also interesting to learn more about how the project was executed from an engineering perspective. The creators have generously published their source code and other details about their implementation to help inspire others – check out their project page here. In short, they used a Rascal MCU that runs Python and has a built-in web server and linked that module to a server, which they connected to Twilio to receive the text messages. When a message comes in, they parse it using a Python script to determine which color is being requested and then send the command to the Light Blades controller (a Color Kinetics iPlayer3 with ColorPlay software).

I love seeing this kind of project and hope it inspires others to create interactive art. Hopefully one of these days Pocobor will have time to put together one of the ideas that have been rattling around the office lately…

Useless Machines

Machines don’t always have a functional purpose; sometimes they are built just to entertain. The machine in the video below takes that concept to a whole new level. It’s only function is to turn itself back off.

After finding this video, I came across an even more awesomely useless machine made by a German hobbyist named Andreas Fiessler. He adapted a broken printer for his machine, which is about the best use I can think of for a broken printer. The video is pretty amusing:

Just in case that video inspires you to make your own, Andreas offers a great description of how he made it happen on his website.

Swarm Robotics + Flying Drones = Awesome

This is a very cool video on swarm robotics. Specifically, it demonstrates how flying drones can work together with ground based robots to accomplish different tasks. Oh, and if you make it to the end of the video you get to find out the ultimate application of this amazing technology.

Village Tech Solutions

Pocobor recently started helping out Village Tech Solutions, an awesome non-profit organization dedicated to providing affordable and relevant technology solutions to the developing world. One of the first systems they developed was the WireBridge (shown below), which is a human-powered river crossing system that has facilitated over 3 million river crossings across deep river gorges in Nepal to date.

One of their current projects is to develop Looma, which is an affordable audio-visual technology device that can provide an interactive window to the internet and access to educational content for village schools that don’t have access to electricity, computers, or even books. The portable, battery powered system integrates a projector with control wand (imagine a Wii controller) so it can act as an electronic whiteboard. It also provides an internet connection over WiFi or any mobile data network if either is available. If not, there is a wide variety of educational content (textbooks, lessons, etc.) stored locally on the device itself to facilitate learning. The system can be recharged from solar panels in villages where the electric grid is not available or is unreliable.

A team of volunteer students from Stanford, Dartmouth, Columbia, Johns Hopkins, George Washington University and Menlo School spent this summer developing an amazing initial prototype. As the fall rolled around and field testing in Nepal begins, there were a few more design tasks that Pocobor started helping out with, including developing a custom power supply for the module and a circuit board for the IR camera used to track the control wand motion.

It’s been a great collaboration and Pocobor is excited to continue helping out with such an interesting and useful project!

Invisible Car

In what is actually a fairly clever marketing gimmick, Mercedes-Benz created an invisible(ish) car for a campaign to boost awareness of their F-Cell hydrogen fuel cell technology prototype (zero emissions = invisible to the enviroment…). My thoughts on fuel cells are a whole other post but I was really interested to see how they pulled off the invisible effect. As you can see from the video, the car is not truly invisible (and is pseudo-invisible only from certain angles) but it is pretty cool experiment nonetheless.

The car is modified with an LED array mounted over the driver’s side of the car and a camera assembly on the passenger side that can transmit the picture from “behind” the car (from the perspective of someone standing off the driver’s side) to the LED array. The idea is that the light waves hit the observer’s eyes from behind the car as if it were not there to block/reflect/etc. any of them. Invisibility systems taking this approach have been an active area of research in defense and other fields for many years and have become fairly sophisticated, particularly for static systems (both object and observer). However, when either the observer or the object (or both) are moving, the problem of sensing and transmitting the appropriate picture with the correct directionality becomes much more difficult.

Even though the car is not truly invisible, the application is effective enough to accomplish the goal for this situation. Look at the faces of the people who see the car… they are surprised, impressed, curious, excited. The car is noteworthy, interesting and cool, and I think that is the biggest takeaway for me. Although Mercedes did not care about boosting the profile of mechatronics with this campaign, they took advantage of technology’s ability to intrigue and inspire people. Mechatronics has the potential to change the world in both meaningful and fun ways, but it requires fuel – engineers, capital, and belief, among other things. Showcase projects like this one can be extremely useful as a way to get people excited about its potential and to encourage people to become engineers or support new technology.

In any case, it’s always nice to see ideas make the leap from science fiction to the real world… eat your heart out, James Bond.

Squishy Circuits

I get really excited when I find groups making electronics more accessible, more interactive, and more fun for young people. Squishy Circuits is using homemade playdough to make prototyping and exploration easy. It’s fun, simple, and a great way to facilitate learning. Playdough has come a long way since I was young; all my playdough did was act like playdough. Check it out:

LED Contact Lenses

Another day, another step closer to the world of sci-fi movies… I saw an article this week on the Elemental LED blog about electronic contact lenses that would allow wearers to view dynamically constructed images on the surface of their eyes. The work, much of which has been occurring at the University of Washington, has been underway for a while (for instance, here is an article from 2008 that gives some more details about the tecnology), but it is a great example of some cutting edge research pathways that I am really excited about for the next few years, including energy harvesting, micro-scale electronics, and bio-compatible systems. I think we are probably a long way away from seeing anything like this on the market but even the progress to date opens up worlds of possibilities. Heads-up displays, indeed.

Arduino Geiger Counter!

A company called Libelium has developed a new add-on (“shield” in Arduino speak) that lets you turn your Arduino into a Geiger counter. Scary that all of a sudden this seems like a good idea. Read more about it here.

Wearable Electronics

Not exactly what I mean.

One of the things I have been excited about lately is the burgeoning area of wearable electronics and e-textiles. Despite the sad fact that the Tron guy might get more mainstream coverage than anyone else in the field, there are actually a bunch of really exciting (and useful) projects in progress around the world. Additionally, although there is certainly some advanced work going on at institutional levels, wearable electronics as a field lends itself well to do-it-yourself (DIY) hacker culture and many of the projects that have grabbed me recently have not come out of corporate or educational behemoths. It is exciting to see cutting edge advancement in a field happen so democratically and I think it bodes well for electronics and smart products more generally that so many people are able to do such great work.

Things have been pretty busy here the last few months; when I started this post I meant to time it for release around the New York Maker Faire eTextile Fashion Show, but I missed that by about 6 weeks. The site is still worth checking out though – it links to some of the people and projects who were there. Anyway, I still want to highlight some of the areas in wearable electronics that have some cool work going on. If you are intrigued by any of these projects, dig a little more – this is the lightest possible scratch on the surface of the space. The Talk2MyShirt blog is a great place to start.


Integrating electronics into clothing in the service of aesthetics (“In matters of cloth he is as fickle as can be / Cause he’s a dedicated follower of fashion”) can be one of the simplest but most accessible forms of wearable electronics. From the sound-responsive equalizer t-shirt you saw someone wearing at the dance club to so-called haute tech fashion (get it?) like Angel Chang’s dress with heat-sensitive ink used to hide a map of Manhattan in the fabric of the dress itself, designers are pushing boundaries at the intersection of clothing, art, fashion and technology.


Wearable electronics is also progressing along more practical lines. Bio-monitoring clothing such as a smart baby monitor onesie that allows parents to monitor their baby’s biometric data and even emotional state from a cellphone or computer is approaching market and offers a wealth of possible uses. Or, consider products like the Frontline Gloves, designed as a gesture-based communication tool for firefighters to use in smoky, low-visibility situations. On a simpler level, there are a wide range of garments available that integrate cell phones, mp3 players or headphones with varying levels of seamlessness.

Where To Next?

In addition to continued progress in the directions designers are already moving, there is one advance on the horizon that I expect to fundamentally change the landscape of wearable electronics (as well as consumer electronics and smart products in general). That area is power harvesting. Right now, nearly all personal electronics, both wearable and otherwise, require frequent recharging of their batteries. However, imagine a world where batteries are recharged automatically as you go about your day. This could happen through harvesting mechanical energy associated with walking around, thermal energy associated with your body, solar energy, or even stray electromagnetic energy from the electronic communication-saturated world in which we live. As the above types of technologies become sophisticated enough to provide meaningful amounts of power, the spectrum of possibility will vastly expand. I can’t wait to see what people come up with to take advantage of it.

Hand Soldering – Part 2

Quad Flat No-Lead Chip

This post builds on my previous post, which discussed hand soldering surface mount passives and QFP chips. As I mentioned last time, these are vital skills for any circuit board designer – the ability to modify or rework a board is integral to a time-effective development process.

Today I’m going to talk a little about hand soldering QFN chips – these chips are extremely small, which can be very useful for tiny, densely packed boards but makes them a little difficult to work with by hand. As a reminder, these posts are building on some excellent tutorials created by Curious Inventor. The relevant information for QFN chips can be found here.

Quad Flat No-lead (QFN) chips are like QFP chips but don’t have leads extending beyond the sides of the chip; instead, they have pads on the bottom of the chip. For these types of chips, however, my experience diverges from the Curious Inventor tutorial a bit. Their method certainly works but I have found it easier and more effective to use solder paste with the hot-air station as opposed to tinning the pads with actual solder. In terms of equipment, you will need good tweezers, a hot air source (either hot air gun or dedicated soldering rework station), solder paste and solder flux.

The technique that we have found works best involves the following steps:

  1. Clean the chip and circuit board pads and make sure that the chip can lie flush on the board.
  2. Apply solder paste on all of the circuit board pads using an applicator syringe (below). Make sure there is paste on all pads but use sparingly – too much could lead to shorts.
  3. solderpaste

    Solder Paste

  4. Place the chip in the correct position on the board using tweezers. The solder paste may make it difficult to see if the chip is correctly aligned with the pads but use silkscreen markings on the PCB to index the chip’s location. Fortunately, surface tension effects with the large center pad will help the chip self-align as long as it is close to being in the correct position. Make sure that the chip is firmly pressed down on the board and is flush or as close as possible to it.
  5. Preheat the chip and board using the hot air gun to about 200 degrees Fahrenheit. Depending on your setup, this can be accomplished by varying the heat and flow rate of the gun or changing the distance between the chip and the hot air nozzle. The chip should remain in place without fixturing as long as the board is horizontal and the hot air is coming orthogonally from above.
  6. Turn up the heat to about 350 or 400 degrees. Once you see the solder melt, continue applying heat for up to 15 seconds more. You want to be sure that the solder has fully melted and reflowed to all of the pads but too long and you can overheat and break the chip and / or board.
  7. There will probably be excess solder along the sides of the chip. Apply flux and use a soldering iron and wick to remove this solder. Try to remove all accessible solder, not just visible accumulations.
  8. Verify that no shorts are visible with a loupe or microscope. Professional shops sometimes use x-rays to check underneath the chip and if this kind of equipment is available, it can be very helpful. However, in our experience it is not necessary.


QFN chip mounted on a PCB

I’d love to hear what works (or doesn’t) for others so feel free to add your two cents in the comments.

Happy Soldering!