A powerful feature of the Raspberry Pi is the row of GPIO (general-purpose input/output). A 40-pin GPIO header is found on all current Raspberry Pi boards.
Any of the GPIO pins can be designated (in software) as an input or output pin and used for a wide range of purposes.
![188681-c06f001 188681-c06f001](https://raspberryautomation.com/wp-content/uploads/2019/03/188681-c06f001-2-e1553632881665.png)