MFC-101 Solid state switch, no moving parts....

[trixdropd]

How is it done?

On my board it looks like only an actuator and spring pressing the pcb directly. Is there stuff sandwiched inside the pcb itself?

Fractal Audio MFC-101 Midi Controller

"Mark III: solid-state switch technology. No moving parts except a spring "actuator". Switching is fully electronic and silent with no switches to wear out. Mechanical lifespan is 1 million actuations"

[anotherjim]

Capacitive touch sensing probably. Usually, that switch type is operated by the user's finger, but in the absence of such a digit, an actuator can be made.

[GGBB]

If the PCB looks something like the pic below, it's the same technology that's in remote controls, game pads etc - momentary switches activated by a conductive pad. When you boil it down, that's very simple technology but in a modern form.