Wiretapped for your protection


Arduino Code for Costumes



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“Searching For Home” Costumes

Kyle Chan and I created these costumes over the last 5 months. The initial designs were based on an earlier version of the piece. Its costume was an early piece from Cyber Optix. The process was as follows:

Sketching initial ideas. The more interesting costumes are conceptual planets. They have their own rings which can be seen as tutus. They have their own set of stars. I found  a costume house that provided the basics of the costume. In this case it was Cicci’s.

Next was prototpying the electronics while Kyle worked on the tutus. I did not have time to do my own boards and early research indicated that I would need to do more programming to get the customized effects I wanted. Given the budget, flexibility, and timing allotted, I went with a Lilypad Arduino solution.

As many of you know Arduino is easy to use for beginners but can be annoying if you are already embedded savvy. As a result I had to allocate more time for tuning. For each costume, I customized according to:

  1. Blue costume- slower relaxed movement utilizing a light sensor to control the ripple rate on the arm. The same sensor controls the colored light flashes.
  2. Red costume- faster twitchy movement based on an accelerometer to control the ripple rate on the arm. Difference accel axises control the colored light flashes.

I created a separate RippleLib and PulseLib to leverage as much of the common code as possible.

Meanwhile, Kyle created the pan tutus. She used plastic boning with the gauzy organza. To enter and exit the tutu, we used snaps along the boning. The tutu is then attached to the trunks.


When costumes, came in, I began sewing in the electronics. Naturally, planning is most of the battle.I attempted to remove the chance of shorting the devices. First, sew in the parts, then connect them, test for shorts, and power up. The connecting was the longest and most arduous.  What if you needed to cross lines? Fortunately, single running stitch can handle this as well as a double layer of fabric can be seen as layers of a PCB.

Other factors to consider is testing the fabric to ensure it isn’t conductive or so thin it doesn’t provide an adequate barrier between trace thread lines.

We finally put it together by sewing snaps to the tutu and the flasher stripe. This design allows ease of attachment to other costumes.


Here is the picture of the pattern I made:


Coding is coming.

To start your own project even with only a basic knowledge of programming and sewing, checkout:

  • http://aniomagic.com/
  • http://web.media.mit.edu/~leah/LilyPad/
  • http://arduino.cc/en/Guide/ArduinoLilyPad
  • http://www.adafruit.com/category/92

Brushing up on basics and beyond with @logicalelegance new book

Elecia White has released her new book on O’Reilly media, “Making Embedded Systems: Design Patterns for Great Software.
Book release
Her initial motivation was to guide another good engineer into arcane and relatively undocumented world of firmware and embedded systems. Disclosure: She’s a friend and I have provided comments on some chapters…and an interview question.

If you have read any of my blog entries you know I am all about this topic. While I have ready many books on the topic, she has formalized what typically I have picked up on the job or by reading articles by Jack Ganssle. I would not hesitate to provide a junior engineer or application software engineer this book to get started. That said, even a seasoned person can gain value from this book. For example, while I have had to optimized code for memory size, she laid out a different procedure that can help hone in on critical spots quickly. Another facet, I enjoyed was that someone finally addressed how to read a datasheet. Sure hardware engineers are already comfortable here but the uninitiated need some guidance and many engineer programs don’t and won’t cover this but this skill is key.

O’Reilly books are generally readable but White improved on this with a whimsical style to keep it fun and interesting. Some of the sections felt a lot like Russell and Norvig classic book on AI. This  topics matched with a bit of silliness in the examples makes learning the material fun and a breeze. The questions at the end test more than the basics. They get you thinking beyond the basics and that’s what I want in anyone I hire for my team start-up or not.

And to the one person who has already commented on my interview question contribution: I really love seeing engineers get a chance to be silly and inventive.

Twinkling star at night

For the High Release Dance Company show piece “Searching For Home,” there were several wearable electronic elements.

  1. A Cyberoptix skirt which features 2 blinking bars
  2. Teal EL wire from Adafruit.com
  3. Twinkling star LED – Only twinkles when it is dark. Turns off when light and shows it with the red led turning on. It is tuneable for different lighting situations using two trim pots. To make your own go to the project page for the schematic and code.

The Open Source Hardware Spec and Why Should You Care

A few weeks ago the initial full release was made of the OSHW specification. The Open Source Hardware spec is the first attempt to start an open source revolution for hardware. At first glance it isn’t terribly interesting. It has a lot of license and definitions about what must be included to be OSHW compliant. And if you are like me, were expecting something more technical and meaty. You are hoping for pin outs or a platform specification, not the mention of documentation that must be written. After reading reading it, I moved quickly onto other things not thinking about the possibilities.

This week I revisited it, thought about why this is important and how it could affect professional hardware people (EEs, MEs, and FWEs). Honestly, I struggled because I wanted the reasoning to have technical merit. I read a few blog posts that pointed out the current issues with trading designs and what that might  mean for hobbyists where tools are not standardized and tool costs matter heavily for design adoption and permeation through the community. I had not considered this problem. Not to mention the uncouth ways that vendors and manufacturers can make it hard to share information later on. It wasn’t until late last night I thought about what the impact could be.

I sense two possibly positive impacts in my work. In my mind, parts vendors are a pain. They want you to sign NDAs for the most mundane of parts. They obfuscate whenever possible for no good reason until you tell them you are looking at other vendors to replace them. I would love it if I could know beforehand if a vendor was held to the standard of providing reasonable documentation as well as let me share my design in the future without a legal gymnastics routine and costly per chip royalties paid out. OSHW provides for that! A vendor with the little logo such as the proposed below:

With a consistent way of allowing for release, distribution, and reuse, the hardware hobbyist community can flourish in a similar manner that the open source software community did. At first, Open Source Software not taken very seriously by the professional community, but in the last 10 years has become a force to be reckoned with. How many times have I had to place a Linux distribution on a microprocessor that was not x86? Too many to count, but each time it gets a bit easier because the OSSW community is updating and refining it to make it easier.  This movement was enough to get WindRiver’s VxWorks to start thinking about Linux and restrategizing due to developers taking their money elsewhere. Perhaps it will be enough to get large vendors to provide more client-favorable sales strategies or at least take their documentation more seriously so more people will be willing to use parts from them.

My second vision of how this could upset the current status quo is based on how it could reshape  rapid prototyping and potentially change the web-driven startup landscape to something more diverse.  Right now, prototyping hardware falls into two camps:

  • cheap and clunky, or
  • expensive, over-kill, and difficult to obtain.

OSHW could allow more iterative design among the community which bring a lot of choice; choices that bring down cost and clunkiness in prototyping.  I could try an idea out faster and closer to my desired specs and form-factor without signing a bunch of NDA’s before I even start to dig in. Sadly, removing this road block saves me days, not just hours. Think about how productive you could be without this. Then roll the fact that in that mechanical drawings, layout, and so forth will also be opened and available. The only thing that could be better is if the design was already FCC certified. How fast could you now deploy? And at what cost savings? We are now talking about development iterations closer to software and web projects. Hardware now has a chance to wrap its head around Agile methodology. And faster development times, mean the possibility of getting to market faster and breaking even sooner. Could this mean VC’s eyes will start looking at hardware again as a good place to invest? One can only hope.

Who is going to She’s Geeky 4: Bay Area?

So who’s going next weekend?

I’ll be around plugging the next Office Hours, a program offering free engineering assistance to entrepreneurs and companies who make physical products.

I hope to see several colleagues from previous years.

Planet moo pinata getting smashed at alison 2.0

Our future robot overlords will take care of us (Please go stand by the stairs)

On one hand this is so silly. On the other, at least people are considering the human interaction that required to make robots acceptable by humans.

Tmobile Defy really is waterproof.

Wow. I am impressed. You can barely hear Obama talk under water. And yes, I do get to do this type of thing at work.

Getting my Kinect Hacks on

After someone hacked the kinect and another person made a MIDI music app back in December, I quickly decided to reverse my decision to buy one. Magically Amazon still had them and I had one in house before the end of the week.

The game responsiveness has improved since I test it out back at a Macy’s in July.

Hooking it up over my XP install with the NUI install has not brought success but in Win7 it worked great. So now I have to consider whether to upgrade or not.

The plan is to use it to control a large Tetris installed in a store window. Whee. Updates should be place in the new project page made just for this idea.