Well I keep meaning to make a better build video/description for this, but suffice to say it's hard when you're moving over a thousand miles away in less than a week.
This is my Halloween costume. It's basically an Arduino microcontroller powered by a 9v battery and running a modified version of the code included in the Knock Tutorial on the website. 12 LEDs are connected in parallel to one output on the Arduino, and are triggered every time I speak into the piezo disk. The piezo is mounted on a sponge to ensure that bonking the helmet won't trigger it, only my voice.
Things I would have done had I had more time:
- Wired the eyes to flicker also when I spoke (currently they are powered independently by another 9v battery)
- Twisted the wiring and shortened the leads on the LED's so I wouldn't be talking sideways into the piezo
- Made a voicechanger, rather than using one bought from a big-box chain store
It scared the bejeezus out of every kid coming to our door. Mission accomplished.