Face buttons (A, B, X, Y) typically use conductive rubber pads, while bumpers and stick-clicks (L3/R3) use tactile micro-switches.
Depending on the model, these use Hall effect sensors or potentiometers to measure pull depth. Xbox 360 Controller Schematic Pdf
The "brain" that processes all inputs and manages communication with the console or PC. Face buttons (A, B, X, Y) typically use
While no single "official" PDF exists, high-quality community resources provide the necessary detail for most projects: Face buttons (A