Sensor-Touch Button

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The product number of Sensor-Touch Button is: MSDS21

Sensor-Touch Button is capacitive touch button sensor module.

Introduction of Sensor Pin

Sensor backpin.png

Touch Button
General Pin Out Sensor / Trinket's Pin Out
PIN3 (SIGNAL-A) Digital Input
PIN4 (SIGNAL-B) Not Connected
  • General Pin Out is the standard pin out of a Sensor / Trinket connector.
  • Sensor / Trinket's Pin Out is this specific Sensor / Trinket's wiring in relation to the General Pin Out.
  • SIGNAL-A / SIGNAL-B are signals that could be digital input, digital output, analog input or analog output. Or special signals such as serial communication (SoftwareSerial, IIC (I2C), etc) or other special signals.
  • Not Connected refers to the Pin not being used for this particular Sensor / Trinket.
  • Read more about the hub module.



  • Sensor voltage
    • 3.3V~5V working voltage
  • Size of the sensor
    • Size of the board: 23.5mm*13mm
    • 1.27mm-spacing 4Pin interface connected with sensorhub.
    • CAD drawing of the sensor: File:Sensor
  • Function description
    • The static signal of the sensor is HIGH. After being touched, the signal changes into LOW.
  • Connection
    • This sensor can be connected to the following interfaces of the core: D2~D13, A0~A7



Basic Functionality

The Touch Button is a simple digital input sensor. It uses the TTP223 chip to detect capacitance when the switch is touched. It is an input module which produces a HIGH or LOW voltage depending if pressed or not. A Core module can read the voltage value and determine the state of the Touch Button.

Touch Button State Table
State Voltage Level
Sensor is not pressed HIGH
Sensor is pressed LOW



The Touch Button is used as a simple input pin. Therefore, the pinMode and digitalRead functions will be used.

Key Functions

  • Required Libraries: None
  • Key Functions:
    • pinMode(pin_number, pin_mode) - sets the mode for the pin
      • pin_number - is the pin number that the sensor is connected to
      • pin_mode - is the mode to set the pin to. Either INPUT or OUTPUT
    • digitalRead(pin_number) - Reads the value of the pin
      • pin_number - is the pin number that the sensor is connected to


This is a simple example which outputs the state of the Touch Button to the serial port terminal.

Note: Important lines of code are highlighted.

//Define the pin the sensor is connected to
const int TOUCH_BUTTON_PIN = 6;

void setup(){
  // put your setup code here, to run once:

  //Initial serial communication port at 9600 baud

  //Configure the pin into input mode

void loop(){
  // put your main code here, to run repeatedly:

  //Perform a digital read and store the value into pin_state variable
  int pin_state = digitalRead(TOUCH_BUTTON_PIN);

  //Check if the sensor's state is HIGH (not pressed)
  if(pin_state == HIGH){
    Serial.println("Touch Button is not pressed!");
  //Check if the sensor's state is LOW (pressed)
  else if(pin_state == LOW){
    Serial.println("Touch Button is pressed!");

  //delay 100ms between loops

Copy and paste the code above to the Arduino IDE or

Download the above example: n/a

  • Open the Serial Monitor (magnifier glass on top right) and set 9600 baud. This will display the serial output.

Program Download


  • Follow the Software Getting Started Guide.
  • Select the Board, Processor and Port.
  • Click [File]->[Open], browse to the project program address, and click "Sensor_Touch Button_Test.ino" to open the program.
  • After confirming all these items are correct, click "→" to download the program to the development board.

Hardware Setup

  • Referring to the following diagram, connect the Sensor-Touch Button to the digital port of Microduino-Sensorhub.

Microduino-sensorhub Crash.JPG


  • After download, open the serial monitor.
  • The static signal of the senor is HIGH. After being touched, the signal changes into LOW.


  • Touching key switch




File:MicroduinoTouch Button-F.JPG
mCookie-Touch Button-Front
File:MicroduinoTouch Button-b.JPG
mCookie-Touch Button-Back
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