Spires is basically a scale arpeggiator theremin made with a laser ’time of flight’ sensor :)
I made it to play ragas, by their nature consiting of ascending and descending passages. Spires also has a continous tone mode so it can play more like a traditional theremin.
For vibrato/volume control, I tried a number of things. In the end, I settled on a simple light sensitive LDR (resistor) since you can place your hand near to it and make fairly ‘fine’ motions like you would doing vibrato on a cello. I like pivoting on a finger just like with a cello much better than free motion above spires.
I wanted it to be small and portable. So it runs on 4 AA batteries. The entire device is dimensioned around the battery holders shape :)
I’m still working on the midi out, but it does output midi already. I’m just thinking about frequency mapping and note gliding and the like …
This is the first attempt on breadboard.
This is the first production version, not quite complete.
Open Sources includes fritzing files, and a folder of firmware. I’ll add the gerber files when the final production run comes in.
There’s a bunch of firmware experiments in progress. I’ll post more information as it becomes ‘stable’.
After I started on this, I found a couple of similar approaches. The Luminiferous uses a more powerful processor (I’m using an arduino 328p) and two TOF sensors, but it similar https://extkits.co.uk/product/luminiferous-theremin-kit/
I’m sure there are others :)