One special feature of the Raspberry Pi is its [<googa>https://www.raspberrypi.org/documentation/usage/gpio/ |GPIO]</googa>, or General Purpose Input/Output connector. This is the strip of pins that runs along one side of the Pi, which acts as a connector to a number of physical inputs or outputs.
This ability to wire up custom physical inputs, switches or buttons, is part of the reason Box Of Stops was written for the Raspberry Pi. Perfect for a bit of DIY organ building.
In [[Configuration mode]], if you click the [[File:Plus.png|middle]] icon to add a trigger to a [[Stop]], [[Coupler]] or [[Combination]] in the usual way, then the screen will wait for you to press the new input button. Assuming everything has been wired up correctly, the screen will then confirm which button you pressed.
== Plugging in a breakout board ==
The other possibility is dedicated Gpio board like the [[Status Board]] from The Pi Hut. This comes pre-wired with sockets for buttons, and LEDs to indicate which controls are active.
== Sharing Gpio inputs with another application on the Pi ==