For this assignment, I programmed an ATTiny85 to run Neopixels when triggered by a capacitive touch sensor. I had a bit of previous experience working with an ATTiny85 + Neopixel combo, and began by trying to recreate that. Initially, I was a bit nervous that the soldering of my programming jig had introduced some integrity issues to the code uploaded to my ATTiny85, but I ran many tests with both Blink and Neopixel’s strand test and found that the jig (and each of my programmed chips) performed just fine.
The implementation of capacitive touch sensing was quite similar to my previous experiences working with it. I placed a 100k ohm resistor across pins 4 and 2 of my chip, using pin 2 as my input or sensing pin. You can see the behavior here:
The housing you see is a junk shelf find. The contraption is powered by two 3V coin cell batteries in series.
Basically, the code on the chip includes small tweaks to the sample code that comes with the Neopixels library and the capacitive sensor library. With a bit more time, I would have soldered my circuit, because as it stands, it is quite fragile.