Thanks for this Allan. I'm stuck on one wall wart due to wanting the design to be usable for other pedals as well. This is mainly my "proof of concept" to design a solution for adding MIDI to any effect pedal which uses analog POTs to control parameters. Most pedals use 9vdc, although some use 12v and even 18v. I'm keeping the scope here to the 9v ones though. So having the circuit not require an additional power supply is very desirable.
I have the resistors and the diode, but I don't have an opamp on hand right now to put this together. I can certainly order one though.
The diagram makes sense to me, except for the following connection points:
- Does point #1 remain "floating" (ie: not connected to anything), or do I need to find the artificial ground within the pedal's PCB and attach it there?
- Is point #2 a connection point, or is it just the line extending on the drawing?
- Where do point numbers 3 and 4 connect on the pedal PCB?
- I'm assuming point 5 is the "5v" pin on the Arduino, and point 6 is the "GND" pin on the arduino, correct?
Thanks again, this is very appreciated.