Chapter 12. Digital Inputs

12.0 Introduction

In this chapter, we look at recipes for using digital components such as switches and keypads. This chapter also covers modules that have a digital output that can be connected to a Raspberry Pi general-purpose input/output (GPIO) acting as an input.

Many of the recipes require the use of a solderless breadboard and jumper wires (see Recipe 9.8).

12.1 Connecting a Push Switch

Problem

You want to connect a switch to your Raspberry Pi so that when you press it, some Python code is run.

Solution

Connect a switch to a GPIO pin and use the gpiozero library in your Python program to detect the button press.

To make this recipe, you will need the following:

Figure 12-1 shows how to connect a tactile push switch using a breadboard and jumper wires.

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Figure 12-1. Connecting a push switch to a Raspberry Pi

An alternative to using a breadboard and tactile switch is to use a Squid Button (Figure 12-2). This is a push switch with female header leads soldered to the end, which you can directly connect to the GPIO connector (Recipe 9.11).

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Figure 12-2. A Squid Button

Open an editor and paste in the following code (ch_12_switch.py ...

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