Very little changed in the circuit, but somehow it still led to the LED lighting up! This quickly turned into turning the paper into the pitchbend control, which worked. Some discoveries, some things I'd guessed would be true:
- Graphite has a really high resistance! When plugged into an analog in, which can take values from 0 to 1023 (0 means the contacts on the test leads are directly touching), the smallest value I've seen in the serial monitor is ~780. If you look at the Arduino code in the post below, change the map line to map(paper, 780, 1023, 0, 127). Still not perfect, but better.
- Having an extra, normal resistor in the circuit is important, as it is inevitable that your leads will touch accidentally at some point. RIP red LED.
- Interacting with the graphite as in the video will probably cause the connection to deteriorate over the course of the piece. In order for the graphite to work, the lines have to be really dark, and it helps if they're thick enough that the performer doesn't accidentally veer out of bounds. Since drawing is important here, the performer will probably have a pencil to correct issues. Or, I could take the slow destruction of the controller as part of its message/design, which could be cool.