esp_touch.ino

const int ledPin =  2;      // the number of the LED pin
const int threshold =  40;      // the number of the LED pin

int ledState = LOW;             // ledState used to set the LED

void setup() {
  // put your setup code here, to run once:
  //pinMode(ledPin, OUTPUT);
  Serial.begin(115200);
  touchAttachInterrupt(T0 , click , threshold );
}

void loop() {    
  Serial.println( touchRead(T0) );
  delay(200);
}

void click () {
  Serial.println("click!");
}