Lesson 21 Button Switch

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Most SunFounder boards already have an LED attached to pin 13 on the board itself. So we will use this LED and a button module to make the LED light up.


– 1*SunFounder Uno board

– 1*USB data cable

– 1*Button module

–  Several jumper wires

Experimental Principle

With the LED attached to pin 13, connect the button module to D8. When the button module inducts button-pressing signals, the LED will be on. Otherwise, it will be off.

Experimental Procedures

Step 1: Build the circuit

Button ModuleSunFounder Uno

Step 2: Program (Please refer to the example code in LEARN -> Get Tutorials on our website)

Step 3: Compile the code

Step 4: Upload the sketch to the SunFounder Uno board

Now, press the button, the LED attached to pin 13 on the SunFounder Uno board will light up.


const int ledPin = 13;//the number of the led pin
const int buttonPin = 8; //the button pin attach to
int val = 0;//variable to store the value read from button
void setup()
  pinMode(ledPin,OUTPUT);//initialize the ledPin as an output
  pinMode(buttonPin,INPUT);//initialize the buttonPin as an intput
void loop()
  val = digitalRead(buttonPin);//read the value from button
  if(val == HIGH)
    digitalWrite(ledPin,LOW);//turn the led off
  else //when pressed
    digitalWrite(ledPin,HIGH);//turn the led on