motorNet – proof of concept

quick video of a potentiometer controlling a servo motor over the interwebs.

arduino -> processing -> PHP [serverside] -> .txt file [serverside] and all the way back on the other computer.

i’ll put up code when it’s all ready to go. as it is, this is ready to go both ways, but for clarity i just filmed it going one way.

these two computers could be thousands of miles apart, just need to be online.

5-volt USB Breakout board

I actually made this back in February (you can see the date etched next to my initials on the board), and never got around to posting about it.   It’s a super simple breakout footprint for a USB mini type-B port.  I wanted to make a really simple way to power my breadboard, and since my computer is usually on my work table, this seemed like a great idea.  I made about 60 of these tiny boards which measure about 2cm x 3cm and hope to sell them as a really cheap, tiny kit one day.

Other than the board itself, the only components necessary are a USB mini type-B port, a 22uF SMT capacitor, and two header pins, which can plug directly into the power rails of your breadboard.  My friend Jen asked me to help her put together a glowing LED circuit inside some ceramic pottery, and part of the concept was that the organic piece would need to plugged into to your computer to ‘live’.  Here are some images of the Arduino Pro Mini powered by my breakout board.

USB 5v Breakout board

USB 5v Breakout board

USB 5v Breakout board

USB 5v Breakout board

USB 5v Breakout board

bootloading an ATMega328 with an Arduino

Awesome! Arduino finally released a tutorial on how to bootload a chip using an Arduino board.

There have been several hacks to do this, but now they have released code to do it legit style!

The tutorial can be found here. I played around with the setup, and successfully did it by inserting my blank chip into another an Arduino, and used a second Arduino with their code uploaded to bootload the firmware. I discovered: 1. This is a feature available only with Arduino0018 (the latest version of the IDE). and cannot use an ATMega168 as the chip performing the bootload. It must be a Duemilanove with a 328 on board.

I then did it with a blank chip in a breadboard with a barebones circuit around it, and an Arduino board uploading to it. Here’s a really blurry, really anticlimactic video of the breadboard setup doing it’s thing. You can see once the bootloading has completed, the chip is no longer blank and begins flashing LED13.

Perfboard Hackduino Instructable!

Finally completed an instructable on how to assume your own $8 Arduino-compatible circuit.  I started last year to spread the word of using ATMega chips outside of the standard blue Arduino board.  There are so many benefits to this including cost and size/shape, but the ability to create entire circuits including other analog or digital parts (opAmps, relays, LED drivers, anything!) is the biggest reason any serious pcomper should know how to do this.

I’ve been busy, and so the hackduino blog has just been pretty much my projects (and a few of Nick Hardeman’s!) that use ATMega chips programmed with the Arduino IDE in completely custom circuits.  No more having to take apart a project just to reuse that bulky $30 Arduino board!! Hackduino 4-eva —

prototyping solar robots!

Amber Krishan, Justin Blinder, and I have begun prototyping solar robots in phys comp. The current goal to is to create a kinetic object, powered using solar energy. The only problem is, solar cells are not the most efficient, reliable, or consistent power source, so it is quite a challenge. Walking/rolling robots have been done sooo many times in so many ways, that we decided a flying robot was the way to go.

solar flying fail #1
"The Emu"

As I mentioned, solar energy is not the easiest to harness, and the key to ‘amplifying’ the power source is using large capacitors and a 1381S74U voltage detector (as well as several PNP and NPN transistors).  The schematic for this 1381-based solar engine came from solarbotics. These components (particularly the caps) add a lot of weight to the structure.  This translates to failure.  We kept the structure as light as possible, using hollow plastics, as little perfboard as possible (in fact the first prototype used a “dead bug” configuration, soldering the legs of each component directly to each other), and thin flexible solar panels.

"the Emu" : solar flying fail #1

In the end, we got all four blades to spin (these are hacked vibration motors), but failed to take off due to excessive weight, and let’s be real: not enough power.  It seems to me that building  really small bots using a photo-popper circuit will be the only way for any real success with solar energy.

"the Emu" : solar flying fail #1

augmented facemask

This was a project I made in June 2009 in Beijing, China. The facemask had green, yellow, and red LEDs that would indicate safe, medium, and dangerous levels of proximity. The project was inspired by the crowded streets of Beijing, and how physical walking down the street could be. The lights would color your face depending on how close something or someone might be to you, emphasizing personal space and public interaction.






EKG-controlled Game of Life Hoodie

I have finally completed my latest : the ” EKG-controlled Game of Life Hoodie “. That’s a wordy title if there ever was one.

First Wear!

The concept here is a wearable version of Conway’s Game of Life, that is controlled by the current state of your life.  Essentially, a wearable extension of your heart, externalized in the form of Conway’s Life. A custom circuit includes an infrared EKG monitor that resets the Game each time a heartbeat is detected. Heartbeat data is analyzed by a hackduino which resets an ATMega48 chip, part of Adafruit’s kit controlling Life, which is embedded in the chest of a hoodie.  Conductive thread is used to connect the 16 LED matrix to the circuit board which is kept in a pocket towards the bottom of the hoodie.

If you are checking this out and are unfamiliar with John Conway’s Game of Life, please read about it, as it is a seminal piece of work, in my opinion one of the most important intersections of art and science.  For the LED matrix playing Life, I used Adafruit’s kit, which is brilliantly designed – able to be daisy chained for larger boards. Unfortunately (or, perhaps, fortunately) I only had one kit to work with, which mean a 4×4, 16 LED matrix. I decided to use red LEDs, as they represent life, blood, and the heart much more to me than green. Also makes this an even better Valentine’s Day gift 😉  I decided that since I was embedding this into a hoodie, I would not need her PCB, which is bulky.  I designed my own breakout for her chip, which you can see in the circuit towards the end of the post.

I used conductive thread to connect each LED from the chest of the hoodie to the pocket holding the circuit and battery, which is lined with an anti-static bag, inside the wearer’s left hip area. The LED embedding technique was picked up from Becky Stern, and worked out quite well. It was, however, a challenging amount of sewing for a novice such as myself, however I accepted the challenge.  I would say it came out functionally ‘great’ and aesthetically ‘ok’.

Check out the flickr set that documents the entire build process.

For detecting heartbeats, I recreated a circuit originally saw on Make, and then through further research found Meng Li‘s project, and finally this schematic – many thanks to Justin Downs for posting his work. The technology here is very simple – an infrared LED (emitter) and detector pair can “see” through your finger: each time blood is pulsed through (= a heartbeat) there is a spike in the amount of light detected.  A LOT of fidgeting and troubleshooting went down in building this circuit, and the result in the video only looks so nice because of a lot of smoothing and averaging done in the code.

Here’s a breakdown of the final circuit I designed to run the hoodie:

It most definitely overkill to be using 2 28-pin ATMega chips for a job that could most definitely be done by one. In Adafruit’s glorious open-sourcery, all code is even posted for their Game! Unfortunately, I do not yet own an AVR programmer and their chip is not bootloaded or supported by the Arduino IDE (the code is all in C). Soon enough I will get my hands on a programmer and if a second version of this arises, I will most certainly use just one chip.

This project would not have happened without Ira Goldberg and Becky Stern.

3 segmented LED display

j-murph made us do something that i still believe is an enormous waste of time. nonetheless, i’m going to make something with it.

here is the display showing infrared range values:

here is the display counting. with elton.

code for a simple counter ( 0 – 999 ) can be downloaded here.