According to this fellow who lists a circuit-bent PSS-15 (same model as this but with a silver control panel), connecting part of the audio output to the keyboard matrix returns can re-trigger ...

In the silicone keyboard, the carbon contact (a ‘pill’) is molded into the silicone button, and the contacts for the keyboard matrix are constructed with traces on a printed circuit board.

Figure 1 This circuit for a 4×3 keyboard shows a more efficient architecture using two CD4017 Johnson counters with only two I/O pins. The example described here showshow to implement this method to ...

Asus' latest mechanical keyboard adds a tiny dot-matrix LED display Customize the look of your keyboard with images and animations By Shawn Knight January 5, 2022, 9:27 9 comments.