High level overview
As we can see in the reMarkable wiki, the reMarkable 2 has 2 USB ports. One is accesssible through the pogo pins on the left-hand side of the device, the other one is the USB-C used for charging and for computer file synchronization. The problem of using the pogo pins is that no cables are available, and that you need to solder your connector (tricky). The problem of using the USB-C port is that the reMarkable USB C port is not powered, so it's not possible to power any device through this port: either you need to use passive devices (tricky) or devices externally powered.
I chose the solution of using the USB C, which an external power for my device.
Some researches have shown that actual tweaked keyboard do actually work, so all I had to do was to create a device that emulates a keyboard sending the proper key strokes when the pedals are pressed.
The global solution can summarized with the following schema:
The physical schema is here:
