Lesson 6 Button Module

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Introduction

In this lesson, we will use button module to control a dual-color LED module.

Required Components

– 1 * Raspberry Pi

 1 * Breadboard

– Several Jumper wires

– 1 * Button module

– 1 * Dual-color LED module

– 2 * 3-Pin anti-reverse cable

Experimental Principle

Use a normally open button as an input device of Raspberry Pi. When the button is pressed, the General Purpose Input/Output (GPIO) connected to the button will change to low level (0V). You can detect the state of the GPIO through programming. That is, if the GPIO turns into low level, it means the button is pressed, so you can run the corresponding code. In this experiment, we will print a string on the screen and control an LED.

The schematic diagram of the module is as shown below:

Experimental Procedures

Step 1: Build the circuit.

Raspberry PiGPIO Extension BoardButton Module
GPIO0GPIO17SIG
3.3V3V3VCC
GNDGNDGND
Raspberry PiGPIO Extension BoardDual-Color LED Module
GPIO1GPIO18R
GNDGNDGND
GPIO2GPIO27G

For C Users:

Step 2: Change directory. 

    cd /home/pi/SunFounder_SensorKit_for_RPi2/C/06_button/

Step 3: Compile.

    gcc button.c -lwiringPi

Step 4: Run.

    sudo ./a.out

For Python Users:

Step 2: Change directory. 

    cd /home/pi/SunFounder_SensorKit_for_RPi2/Python/

Step 3: Run.

    sudo python3 06_button.py

The LED on the module will emit green light. If you press the button, “Button pressed” will be printed on the screen and the LED will emit red light. If you release the button, “Button released” will be printed on the screen and the LED will flash green again.