Chapter 11. Digital Inputs
In this chapter, we look at recipes for using digital inputs, such as switches and keypads. This chapter also covers modules that have a digital output that can be connected to a Raspberry Pi input.
Most of the recipes require the use of a solderless breadboard and male-to-male jumper wires (see Recipe 8.10).
11.1. Connecting a Push Switch
Be sure to check out the accompanying video for this recipe at http://razzpisampler.oreilly.com.
You want to connect a switch to your Raspberry Pi so that when you press it, some Python code is run.
Connect a switch to a GPIO pin and use the RPi.GPIO library in your Python program to detect the button press.
To make this recipe, you will need:
Figure 11-1 shows how to connect a tactile push switch, using a breadboard and jumper wires.
Open an editor (nano or IDLE) and paste in the following code. As with all the program examples in this book, you can also download the program from the Code section of the Raspberry Pi Cookbook website, where it is called switch.py.
This example code displays a message when the button is pressed: