Arduino - Touch Sensor Toggle LED

In a previous tutorial , We have learned how to turn on the LED if the touch sensor is touched, and turn off LED if the touch sensor is released. In this tutorial, We are going to learn how to toggle LED each time touch sensor is touched.

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×Touch Sensor
1×LED
1×220 ohm resistor
1×Breadboard
4×Jumper Wires
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About LED and Touch Sensor

If you do not know about LED and touch sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino Touch Sensor LED Wiring Diagram

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Arduino Code - Touch Sensor Toggles LED

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-touch-sensor-toggle-led */ // constants won't change const int TOUCH_SENSOR_PIN = 7; // Arduino pin connected to touch sensor's pin const int LED_PIN = 3; // Arduino pin connected to LED's pin // variables will change: int ledState = LOW; // the current state of LED int lastTouchState; // the previous state of touch sensor int currentTouchState; // the current state of touch sensor void setup() { Serial.begin(9600); // initialize serial pinMode(TOUCH_SENSOR_PIN, INPUT); // set arduino pin to input mode pinMode(LED_PIN, OUTPUT); // set arduino pin to output mode currentTouchState = digitalRead(TOUCH_SENSOR_PIN); } void loop() { lastTouchState = currentTouchState; // save the last state currentTouchState = digitalRead(TOUCH_SENSOR_PIN); // read new state if(lastTouchState == LOW && currentTouchState == HIGH) { Serial.println("The sensor is touched"); // toggle state of LED ledState = !ledState; // control LED arccoding to the toggled state digitalWrite(LED_PIN, ledState); } }

Quick Steps

  • Connect Arduino to PC via USB cable
  • Open Arduino IDE, select the right board and port
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • Keep touching the touch sensor several seconds and then release it.
  • See the change of LED's state

Code Explanation

Read the line-by-line explanation in comment lines of code!

In the code, ledState = !ledState is equivalent to the following code:

if(ledState == LOW) ledState = HIGH; else ledState = LOW;

Video Tutorial

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