What is distance sensing
The Touch Board can work without touch too. Try distance sensing (proximity).
Although it’s called the Touch Board, what the electrodes are really doing is sensing proximity via capacitive sensing. When you set a sensors’ thresholds to be relatively high, the Touch Board only responds to actual contact or touch, rejecting proximity events.
If you want the Touch Board to sense something from further away, or even through an insulation such as glass or plastic, you can lower each sensors’ threshold to increase sensitivity — turning the Touch Board into a ‘Proximity Board’.
If you would like to change the sensitivity of one or more of the electrodes on your board, just follow the proximity tutorial.