Capacitive Touch Pad 16-Key - TTP229 4x4 Keypad 270 degree and others with the same

and others with the same form factor

and modules

S (signal) → D8 (or any digital pin)

and your preferred sensors for line following or obstacle detection

heatsinks help the components to breathe and make their functions more appropriately

Capacitive Touch Pad 16-Key - TTP229 4x4 Keypad 270 degree and others with the same16 key capacitive touch pad on the TTP229 IC. Drop in swap for mechanical buttons, with no moving parts to wear out. Pads extend over wire and detect touch through glass, plastic, fabric or wood, so you can hide controls behind a panel. Built in auto calibration, works with Arduino or standalone. Specs Chip TTP229 Keys 16 capacitive Voltage 2. 4 5. 5V Modes Fast low power selectable Response ~100ms fast, ~200ms low power Output Direct toggle, CMOS