Poetaster's Tonetoys

spires

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.

a scale monster

The completed version seen here sends midi and here are two examples of playing duets (with a neutron):

Here playing a traditional mode (spires has all of them 7 times 12) …

And here playing a raga (sort of :) …

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 :)

If you would like to purchase a completed version, it’s available on etsy at https://tonetoys.etsy.com/listing/1872836278 or you can buy it directly for 73 euros from me.

If you want to DIY: Open Sources includes fritzing files, and a folder of firmware. Gerber files are also in the repo, so you can just directly have it made by a pcb house….

Instructions

It’s kept fairly simple :)

  1. At startup, Spires is in the Modal program bank. Turning the encoder wheel (black thingy) selects: Ionian, Dorian, Phrygian, Lydian, Mixolodian, Aeolian, Locrian. In the traditional order
  2. Pressing the encoder button down in a mode increments the root/key, for all 12 from C to B. So you can play all the modes in any key.
  3. Hold the encoder button down and turn the encorder to change program bank
  4. In all program banks except the first, modal, pressing the encoder button short once switches to the chromatic and short click twice for scale mode.
  5. Long pressing (3 seconds) in any program bank but the first and the encoder button switches between sine wave and triangle.
  6. At the back is a small switch which lets you turn off the light dependant resistor which can be handy, for instance, in the dark :)

That’s it, really.

Older material

This is the first production version, not quite complete.

This is the first attempt on breadboard.

Firmware

There’s a bunch of firmware experiments in progress. I’ll post more information as it becomes ‘stable’. To install or update firmware use https://poetaster.org/webflasher , the chrome based flasher, with the limitation that it works in edge and chrome only. Of couse, you can get the source on github and just use the arduino ide :)

Other projects like it ….

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 :)