Lesson 15 Touch Switch



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.


  • 1 * SunFounder Uno board

  • 1 * USB data cable

  • 1 * Touch Switch module

  • 1 * 3-Pin anti-reverse cable


In this experiment, 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.


Experimental Procedures

Step 1: Build the circuit


Step 2: Open the code file

Step 3: Select correct Board and Port

Step 4: Upload the sketch to the SunFounder Uno board


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 13 on the SunFounder 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.