For the prototype I split up the two features: the sound and the color output. I separated the two for now because I am still working on the mapping the correlation of color parameters and sound. For the color prototype I am using a neopixel ring that is changing in Hue, Saturation and Brightness values from 3 potentiometers mapped to each parameter. For the sound part, I am for now sticking to what the arduino and ATTiny is capable with producing sound, 8-bit tones. The pitch and duration of the notes are controlled with two separate potentiometers. For the future iteration I will look into filter ICs and develop the arduino code so that it can play more complex melodies instead of just the one pitch that is controlled by the changing potentiometer values.
Initially, I was following a step-sequencer instructable that uses an ATTiny to get a sense of what is possible with a small chip. I did not manage to get it to work as intended but learned a few things along the way while troubleshooting the issues I was running into.
Things I learned and figured out:
The speaker (4ohm 3W) I was using did not sound loud enough. I knew I needed a transistor but I had to do some research to figure out what kind actually works for this application. After some digging I learned that BJT NPN types can amplify audio because the current from the Base will act as a multiplier as it joins the current from the Collector.
The author for the instructable was reading both a switch and a potentiometer from a single pin on the ATTiny because they ran out of pins on this very limited chip. The pin would be reading analog values and since potentiometers have a minimum resistance, if the analog value fell below that minimum resistance then logically the switch (connected to ground and the internal resistor set to pull up) would be on.
Next Steps:
Design the musical correlation between sound and color
Look into other ways I can manipulate the sound using perhaps filter ICs
Try to combine the two parts together onto one ATTiny
Step - sequencer board
Simplified “instrument” board
Bill of Materials - link to spreadsheet
