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
1	×	Jumper Wires
1	×	(Optional) 9V Power Adapter for Arduino
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno
1	×	(Optional) Transparent Acrylic Enclosure For Arduino Uno

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.

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

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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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Touch Sensor and LED on Commercial Products

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