Talking to Pocket Operators over i2c / use with Eurorack

Is it possible to use the pads on the back to access the i2c bus?

My end goal is to be able to inject certain settings on wake using a teensy or something, in order to bypass having to manually press buttons in order to get the setup I need.

I have been able to sync the PO's clock using a triangle wave from an LFO, but this requires putting the PO's into one of 4 (?) sync modes. I also need to be able to set the WRITE button to off in order to trigger the sounds on button press.

Hoping @punji sees this as i have seen a dump of i2c commands on his blog, but anyone else with knowledge/experience using the back pads on the PO's i'd love to hear from!


Hi Warren, the PO only uses I2C for controlling its CODEC. They could have implemented some code to allow an external device to inject key events or control the sound engines, since the exposed pads at the back are properly wired to an I2C interface, but they simply missed that. Now there is nothing we can do about it, unless we replace the original firmware. Of course, there is always the brute force approach by soldering wires to the keypad switches…

Hi Warren,

I’ve used the brute force approach soldering to the keypads - I used a Teensy 3 to drive it to let me connect the PO as a midi device and sequence it from a DAW.

For you’re use, simulating button presses to set it up would be easy as long as you were sure of the starting configuration (if I was doing it I would probably interrupt the power so I knew I was starting with it in a known state.

It looks messy with all the wires but I couldn’t find any other way of controlling it externally- if you find one let me know! cheers Paul