1B13 TTP229 16-Channel Digital Capacitive Switch Touch Sensor Module

The 4×4 Keypad features a total of 16 buttons in matrix form. This module can be adjusted in different modes. The most important ones are as follows:

• Two TP2 pins are open-circuit. In this mode, only 8 output pins are active to use 8 touch keys. By touching each key, its relevant pin becomes HIGH, and by releasing it, it becomes LOW again.
• Two TP2 pins are short-circuiting; in this mode, two serial pins are active to use all 16 touch keys. You can only touch one key at a time.

TTP229 Capacitive Touch Keypad Pinout

This module has 12 pins:

• VCC: Module power supply: 2.4-5.5V
• GND: Ground
• SCL: Input pin for Serial Clock
• SD0: Output pin for Serial Clock
• Out1: Digital Output pin 1
• Out2: Digital Output pin 2
• Out3: Digital Output pin 3
• Out4: Digital Output pin 4
• Out5: Digital Output pin 5
• Out6: Digital Output pin 6
• Out7: Digital Output pin 7
• Out8: Digital Output pin 8

You can see the pinout of this module here.

Required Materials

Hardware Components

Arduino UNO R3	×	1
4x4 TTP229 Capacitive Touch Keypad	×	1
Male to Female Jumper wire	×	1

Software Apps

Arduino IDE

Interfacing 4x4 TTP229 Capacitive Touch Keypad with Arduino

Step 1: Circuit

The following circuit shows how you should connect Arduino to TTP229 module. Connect wires accordingly.

Step 2: Code for 8 Key Mode

Upload the following code to Arduino. Note that for this mode, two TP2 pins must be open-circuit.

void setup(){
  for(int x=2;x<10;x++)
  pinMode(x,INPUT);
  Serial.begin(9600);
}

void loop(){
  for(int y=2;y<10;y++){
    if (digitalRead(y)==HIGH)
    Serial.println(y-1);
  }
}
  

  /* Define the digital pins used for the clock and data */
#define SCL_PIN 10
#define SDO_PIN 11

/* Used to store the key state */
byte Key;

void setup()
{
  /* Initialise the serial interface */
  Serial.begin(9600);
  /* Configure the clock and data pins */
  pinMode(SCL_PIN, OUTPUT);  
  pinMode(SDO_PIN, INPUT); 
}
* Main program */
void loop()
{
  /* Read the current state of the keypad */
  Key = Read_Keypad();
  
  /* If a key has been pressed output it to the serial port */
  if (Key)
    Serial.println(Key); 

  /* Wait a little before reading again 
     so not to flood the serial port*/
  delay(100);
}


/* Read the state of the keypad */
byte Read_Keypad(void)
{
  byte Count;
  byte Key_State = 0;

  /* Pulse the clock pin 16 times (one for each key of the keypad) 
     and read the state of the data pin on each pulse */
  for(Count = 1; Count <= 16; Count++)
  {
    digitalWrite(SCL_PIN, LOW); 
    
    /* If the data pin is low (active low mode) then store the 
       current key number */
    if (!digitalRead(SDO_PIN))
      Key_State = Count; 
    
    digitalWrite(SCL_PIN, HIGH);
  }  
  
  return Key_State; 
}