Arduino - Touch Sensor - Relay

We are going to learn how to:

Turn on relay if the touch sensor is touched.
Turn off relay if the touch sensor is NOT touched.

We will learn how to toggle relay each time touch sensor is touched in Arduino - Touch Sensor Toggles Relay tutorial.

By connecting relay to light bulb, led strip, motor or actuator... We can use the touch sensor to control light bulb, led strip, motor or actuator...

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B (for USB-A PC)
1	×	USB 2.0 cable type C/B (for USB-C PC)
1	×	Touch Sensor
1	×	Relay
1	×	Jumper Wires
1	×	(Optional) Solenoid Lock
1	×	(Optional) 12V Power Adapter
1	×	(Optional) DC Power Jack
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno
1	×	(Recommended) Breadboard Shield For Arduino Uno
1	×	(Recommended) Enclosure For Arduino Uno

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some links in this section are Amazon affiliate links. If you make a purchase through these links, we may earn a commission at no extra cost to you.
Additionally, some links direct to products from our own brand, DIYables.

About Relay and Touch Sensor

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

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Arduino Code

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-touch-sensor-relay */ const int TOUCH_SENSOR_PIN = 8; // Arduino pin connected to touch sensor's pin const int RELAY_PIN = A5; // Arduino pin connected to the IN pin of relay void setup() { Serial.begin(9600); // initialize serial pinMode(TOUCH_SENSOR_PIN, INPUT); // set arduino pin to input mode pinMode(RELAY_PIN, OUTPUT); // set arduino pin to output mode } void loop() { int touchState = digitalRead(TOUCH_SENSOR_PIN); // read new state if (touchState == HIGH) { Serial.println("The sensor is being touched"); digitalWrite(RELAY_PIN, HIGH); // turn on } else if (touchState == LOW) { Serial.println("The sensor is untouched"); digitalWrite(RELAY_PIN, LOW); // turn off } }

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

Touch and keep touching the touch sensor several seconds
See the change of relay's state

Code Explanation

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

Video Tutorial

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Touch Sensor and Relay on Commercial Products

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