What's going on here?

[dano12]

This is from https://www.thomann.de/gb/stompenberg_devices.html



So the microcontrollers connected via ethernet to the web server. And the the microcontrollers to individual pedals where controls have been replaced with PCBs:



I get the relay PCBs for replacing the switches on a pedal. But what about the other board...it appears to be quad opamp but somehow configured as a variable potentiometer? Any ideas on how to accomplish that?

Oh yeah, and the overall idea is extremely bad-ass!

[iainpunk]

digital potentiometer chips 
this video got me in to pedal designing, i remember when it came out in my first year of middle school, he's been a huge inspiration to me!

cheers

[matmosphere]

Wow, I saw a link to that pedal test website, I never imagined that anything like this was behind it. That is some pure mad scientist level stuff there, I love it!