?Can also be used on Ev3?
Using the NXT brick, the touch sensor detects pressure – i.e. when the button is pressed or released. The sensor is also able to count single press and multiple presses. A LEGO cross axle can be attached to the sensor button. You will need a connector cable, which is included in the 9797 Base Set.

The analog EV3 Touch Sensor is a simple but exceptionally precise tool that detects when its front button is pressed or released and is able to count single and multiple presses.