Touch Toggle

Note

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Kit purchase

Looking for parts? Check out our all-in-one kits below — packed with components, beginner-friendly guides, and tons of fun.

Name	Includes Arduino board	PURCHASE LINK
Ultimate Sensor Kit	Arduino Uno R4 Minima	BUY
Elite Explorer Kit	Arduino Uno R4 WiFi	BUY
3 in 1 Ultimate Starter Kit	Arduino Uno R4 Minima	BUY
Universal Maker Sensor Kit	×	BUY

Course Introduction

This Arduino project uses a touch sensor and a traffic light LED module to simulate a simple traffic light system. Each time the touch sensor is pressed, the LEDs switch in sequence from red to yellow to green. This example demonstrates how to use a touch sensor as an input trigger to control multiple LEDs in a sequence.

Note

If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.

• 1.1 Install Arduino IDE(Important)

• 1.2 Introduce of Arduino IDE

Required Components

In this project, we need the following components:

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	Arduino UNO R4 Minima	1	BUY
2	USB Type-C cable	1
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	Touch Sensor Module	1	BUY
6	Traffic Light LED	1	BUY

Wiring

Common Connections:

• Traffic light LED

  • R: Connect to 7 on the Arduino.

  • Y: Connect to 8 on the Arduino.

  • G: Connect to 9 on the Arduino.

  • GND: Connect to GND on the Arduino.

• Touch Sensor Module

  • SIG: Connect to 2 on the Arduino.

  • GND: Connect to breadboard’s negative power bus.

  • VCC: Connect to breadboard’s red power bus.

Writing the Code

Note

• You can copy this code into Arduino IDE.

• Don’t forget to select the board(Arduino UNO R4 Minima/WIFI) and the correct port before clicking the Upload button.

/*
  The code controls a traffic light LED module with a touch sensor.
  Once the touch sensor is activated, the LEDs cycle through turning
  on in sequence: Red -> Yellow -> Green.

  Board: Arduino Uno R4 (or R3)
  Component: Touch Sensor Module and Traffic Light Module
*/

// Define pins for touch sensor and LEDs
const int touchSensorPin = 2;  // touch sensor pin
const int rledPin = 7;         // red LED pin
const int yledPin = 8;         // yellow LED pin
const int gledPin = 9;         // green LED pin

int lastTouchState;     // the previous state of touch sensor
int currentTouchState;  // the current state of touch sensor
int currentLED = 0;     // current LED 0->Red, 1->Yellow, 2->Green

void setup() {
  Serial.begin(9600);              // initialize serial
  pinMode(touchSensorPin, INPUT);  // configure touch sensor pin as input

  // set LED pins as outputs
  pinMode(rledPin, OUTPUT);
  pinMode(yledPin, OUTPUT);
  pinMode(gledPin, OUTPUT);

  currentTouchState = digitalRead(touchSensorPin);
}

void loop() {
  lastTouchState = currentTouchState;               // save the last state
  currentTouchState = digitalRead(touchSensorPin);  // read new state

  // check if the touch sensor was just touched
  if (lastTouchState == LOW && currentTouchState == HIGH) {
    Serial.println("The sensor is touched");

    turnAllLEDsOff();  // Turn off all LEDs

    // switch on the next LED in sequence
    switch (currentLED) {
      case 0:
        digitalWrite(rledPin, HIGH);
        currentLED = 1;
        break;
      case 1:
        digitalWrite(yledPin, HIGH);
        currentLED = 2;
        break;
      case 2:
        digitalWrite(gledPin, HIGH);
        currentLED = 0;
        break;
    }
  }
}

// function to turn off all LEDs
void turnAllLEDsOff() {
  digitalWrite(rledPin, LOW);
  digitalWrite(yledPin, LOW);
  digitalWrite(gledPin, LOW);
}