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