Available as an assembled Module and as a DIY project.
This Module is currently available.
Small Form Factor VCO
A VCO, albeit a microcontroller-based one, in 2HP? Yes indeed.
Obviously, given the limitations of the 2HP form factor you're not going to find huge amounts of functionality - there's an input for pitch CV and an output for the PWM filtered waveform, plus pots for pitch CV attenuation and waveform selection - if you want to break out the generated PWM signal then there's a pad on the PCB for that; there's not enough space on the front panel to break it out there, at least on this iteration.
Despite the 2HP form-factor I've decided to stick with a through-hole microcontroller - in fact the entire module is through-hole apart from a pair of 0805 resistors mounted behind the control pots. I did consider using a surface-mount controller but reprogramming SMD controllers isn't exactly user-friendly (the upshot of this is that a PCB/panel set might appear at some point)
The oscillator has a range of around 5 octaves, but be aware that the V/oct tracking will not be perfect - this is due to the limitations of using the internal clock on the microcontroller plus a 10-bit DAC. You can get round this if you're willing to tinker with the firmware.
Works best with a sequencer, and the base frequency is around 32Hz.
The firmware is largely the same as I've used for past microcontroller-based VCOs, apart from necessary tweaks to allow it to build and run on an ATTiny85 . The firmware is made available under a permissive license and you are positively encouraged to do interesting things with it.
