I want to build a little box with switches, so that I can flip a switch and it will hold down a keyboard key on my PC. My idea is to take the little PCB from an existing keyboard (a Microsoft Wired 600) and figure out the grid locations for keys of my choice. "W" would be a good one, since it's "forward" in many games and needs holding down a lot, leading to a roaring case of RSI.
The pcb has an edge connector that presses against the keyboard membrane, the contacts are small, but not too small, but they're covered in this black stuff. It doesn't look like it's solderable. So any ideas? Do I use conductive glue? Could I scrape it off and find metal underneath? I'm asking if anyone has experience with this, what did you do?