The Nintendo Switch, with its dual removable controllers and ability to be used as both a handheld and TV-based gaming console, has become quite popular. One small annoyance, however, is that its Joy-Con analog sticks sometimes suffer from drift. Matteo Pisani decided he could fix this by eliminating the joystick altogether, instead subbing in a capacitive trackpad.
Pisani outlines his hack in a well-detailed Medium post, and while challenging, the process looks relatively straightforward. The analog joystick is simply a two-channel potentiometer setup plus a pushbutton, connected to the main Joy-Con board via a 0.5mm pitch flexible cable. He was able to find a circular capacitive sensor, with 63 levels of pressure sensitivity to simulate a push, and subbed this input in with a dual-channel ADC. An Arduino Pro Mini is used for control and to take care of the proper mapping.
All the bits are soldered onto a small PCB, which was attached to the Joy-Con with double-sided tape, then covered with Kapton tape for protection. Power and connection are a provided by ribbon cables and a slot in the Joy-Con itself, and though the build doesn’t appear to be stock, it does look quite usable.
Pisani is currently working on a new PCB that could sit inside of the controller in place of the analog joystick, and he's actually considering developing this into a sellable product. If you want to support this endeavor, he has shared a donate link in his write-up.