Easy Basics: Project 017a Touch Switch

of Acoptex.com in UNO

Basics: Project 017a

Project name: Touch Switch sensor

Attachments: sketch

In this project, you needed these parts :

1.Aruduino Uno R3 (you can also use the other version of Arduino)

2.Arduino IDE ( you can download it from here  )

3.Jumper cables

4. Resistor 1 pc (220 Ohm)

5. Breadboard

6. Touch switch 1 pc

7. LED 1 pc (red)


In this project we will learn how to connect touch sensor to Arduino board. 

Understanding the touch sensor

A metal touch sensor is a type of switch that only operates when it's touched by a charged body. It has a high-frequency transistor which is energized when receiving electromagnetic signals.

In this project, touch the base electrode of the transistor to make it conduct electricity, for human body itself is a kind of conductor and an antenna that can receive electromagnetic waves in the air.

When the module is electrified, the original state of pin SIG is low and the LED onside is on. Now, touch the electrode with your finger. Then it outputs high and the LED on it and that attached to pin 12 on the Arduino Uno board will go out. Move away and touch it again, and it'll output low with the LEDs turned on, and so forth. Thus, the output level changes between high and low with each touch, together with LEDs brightening and dimming.  

Signals and connections of touch sensor

The touch sensor has 3 pins: VCC (+5V), GND, SIG. VCC pin connected to Arduino board 5V, GND connected to Arduino board GND and SIG (Signal) connected to any Arduino board digital pin from 2 to 13.

Signals and connections of LED

The operating voltage of the LED is 1.8V and the operating current is 10mA-20mA. The Arduino Uno board can supply 5V or 3.3V power. We will use 5V for this project, so the minimum resistance of the current limiting resistor should be (5 V to 1.8 V)/20 = 160 Om. The 220 Om offered in the kit is suitable and you can also choose other resistors that meet the condition. The larger the resistance is, the dimmer the LED will get.

Build the circuit

The following picture shows the needed connections with the Arduino Uno 

Step by Step instruction

  1. Plug your Adruino Uno board into your PC and select the correct board and com port
  2. Open up serial monitor and set your baud to 9600 baud
  3. Verify and upload the the sketch to your Adruino Uno board
  4. When you touch the sensor the LED is off


We have learnt how to connect touch sensor to Arduino board


  • No libraries required for this project


  • See attachment on the begining of this project description. 

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Published at 11-08-2017
Viewed: 861 times