Responding to a button
Many applications using the Raspberry Pi require that actions are activated without requiring a keyboard and screen to be attached to it. The GPIO pins provide an excellent way for the Raspberry Pi to be controlled by your own buttons and switches without a mouse/keyboard and screen.
Getting ready
You will need the following equipment:
- 2 x DuPont female-to-male patch wires
 - Mini breadboard (170 tie points) or a larger one
 - Push-button switch (momentary close) or a wire connection to make/break the circuit
 - Breadboard wire (solid core)
 - 1K ohm resistor
 
The switches are as shown in the following diagram:

The push-button switch and other types of switch
Note
The switches used in the following examples are single-pole, single-throw (SPST), momentary close, push-button switches. Single pole (SP) means that there is one set of contacts that makes a connection. In the case of the push switch used here, the legs on each side are connected together with a single-pole switch in the middle...