STS VS eurorack-awesome

We’ll, I made a thing that does that, it’s a sample player that has a Control Voltage input to select the sample being played back (0-5V is divided into 10 regions that select one of 10 samples in a bank). It’s got a lots of other features you don’t need, but it’s a place to start. Uses the STM32F427 chip and an external codec via SAI/I2S firmware: https://github.com/4ms/STS

For open source gerbers you can send off to get made there is lots of stuff out there. This is a big list on Github. I've built the nickajeglin analog logic module which is really good. Maasijam has some really good stuff as well.

There's a good list in Eurorack-awesome although many are analog designs.

if you’re okay with 0-5v cv there are lots of references like https://github.com/mattb/teensy-cv. more here https://github.com/newdigate/eurorack-awesome

A good place to start is sdiy and the legendary modwiggler forum modwiggler or github. github

With that background, if you're comfortable with schematics and doing pcb layouts, open-source modules can be the cheapest way to go. Here is a link with a bunch of github repos. Some have gerber files, you can send off to somewhere like JLCPCB to have the panels and PCBs made. Minimum order is 5 I think.

You can get a lot cheaper with some of the open source stuff out there. Here is a link with a lot of stuff. You'll have to source companies to do panels and pcbs.