HOW to Use Capacitive Sensor with ESP32

Description

In this kit, there is a capacitive touch module which mainly uses a TTP223-BA6 chip. It is a touch detection chip, which provides a touch button, and its function is to replace the traditional button with a variable area button. When we power on, the sensor needs about 0.5 seconds to stabilize.

Do not touch the keys during this time period. At this time, all functions are disabled, and self-calibration is always performed. The calibration period is about 4 seconds. We display the test results in the shell.

Working Principle

When our fingers touch the module, the signal S outputs high levels, the red LED on the module flashes. We can determine if the button is pressed or not by reading high and low levels on the sensor.

Required Components

Connection Diagram

Test Code

//*************************************************************************************
/*
 * Filename    : Touch sensor
 * Description : Reading touch value
 * Auther      : http://www.keyestudio.com
*/
int val = 0;
int touch = 15; //The key of PIN  
void setup() {
  Serial.begin(9600);//Baud rate is 9600
  pinMode(touch, INPUT);//Setting input mode
}

void loop() {
  val = digitalRead(touch);//Read the value of the key
  Serial.print(val);//Print out key values
  if (val == 1) {//Press for high level
    Serial.print("        ");
    Serial.println("Press the button");
    delay(100);
  }
  else {//Release to low level
    Serial.print("        ");
    Serial.println("Loosen the button");
    delay(100);
  }
}
//*************************************************************************************

Code Explanation

When we touch the sensor, the Shell monitor will show“Pressed the button!”, if not,“ Loosen the button!”will be shown on the monitor.

Test Result

Connect the wires according to the experimental wiring diagram, compile and upload the code to the ESP32. After uploading successfully，we will use a USB cable to power on，open the serial monitor and set the baud rate to 9600.

The serial monitor will display the corresponding data and characters. when the button is pressed, the red LED lights up and val is 1. Then the shell shows “Pressed the button!”; if the button is released, the red LED is off and val is 0,“Loosen the button!”will be displayed.