TTP223 capacitive touch button with ESP32

Supply 3.3-5 V Bus GPIO

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VCC	Power	3V3
SIG	Output (the part drives it)	D25	HIGH while touched (default mode)
GND	Ground	GND

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

void setup() {
  Serial.begin(115200);
  pinMode(25, INPUT);  // SIG
}

void loop() {
  Serial.println(digitalRead(25));
  delay(100);
}

Tontek TTP223 datasheet, Supply 2.0 to 5.5 V; direct output mode active HIGH by default

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.