Raspberry Pi With Processing – Push Button – Lesson 3

In the third lesson, we are going to learn to interface a momentary push button with Raspberry Pi and program to display some output on the screen when the push button is pressed.

Hardware Required

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Raspberry Pi 3b+ cart iconcart iconcart icon
Micro Push Buttoncart iconcart iconcart icon

Circuit

  • Connect the 3.3v of Raspberry Pi to one of the terminal of Push Button.
  • Connect the GPIO 4 (Physical pin 7) of Raspberry Pi to the other terminal of Push Button.
  • Connect a pull down resistor from GPIO 4 to GND.

Code

//  https://diyusthad.com
//  https://youtube.com/diyusthad

import processing.io.*;

// On the Raspberry Pi GPIO 4 is physical pin 7 on the header

void setup() {
  GPIO.pinMode(4, GPIO.INPUT);
  background(0);
}

void draw() {
  if (GPIO.digitalRead(4) == GPIO.HIGH) {
    // button is pressed
    fill(255,0,0); // color changes to RED
  } else { 
    // button is not pressed
    fill(0,204,0); // color changes to Green
  }
  ellipse(width/2, height/2, width*0.75, height*0.75); // to draw a circle
}

Output

When Button is released

When Button is pressed

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