Capacitive Touch Disk Pad

1. Capacitive Touch Disk Pad

Keyboard Capacitive Touch Disc Pad (https://robotdyn.com/capacitive-touch-disk-pad.html) consists of 15 touch buttons. This compact, inexpensive keyboard can be connected to any capacitive module. It is a full-featured touch keyboard that can be easily integrated into a professional control system or microcontroller application. Touch panels are numbered from 1 to 15. Buttons can be marked with a marker pen. Included: Board and jumper and FF wires 150mm long.

2. Connecting to ESP8266

Consider connecting the keyboard to the WI FI Modem Board on the ESP8266 module (https://robotdyn.com/wifi-nodem-esp8266-32m-flash-ch340g.html). To connect, we will use a 16-key capacitive touch module 16 Keys Capacitive touch HTTP 229 I2C module (https://robotdyn.com/16-keys-capacitive-touch-ttp229-i2c-module.html), which connects to the microcontroller over the I2C bus.

Connection according to the connection diagram:

3. Sketch of the definition of the pressed key on the keyboard in C (Arduino IDE)

Let's write a sketch to determine the pressed keys on the touch keyboard and output them to the serial port. The contents of the sketch:

// include libraries
#include "Wire.h"
/ / TTP229 address
#define TTP229_LSF 0x57

void setup() {
   // start I2C
   Wire.begin(0,2);
   // starting the serial port
   Serial.begin(9600);
}
// getting I2C data
void getTTP229data(byte *a, byte *b) {
   // request 2 bytes from TTP229
   Wire.requestFrom(TTP229_LSF, 2);
   int dataN = 0;
   while(Wire.available())
      {
      // getting bitwise
      char c = Wire.read();
      if (dataN == 0) *a = c;
   if (dataN == 1) *b = c;
   dataN++;
   }
}
/ / show received data
void showTTP229data() {
   byte aa,bb = 0;
   getTTP229data(&aa,&bb);
   Serial.println();
   printByte(aa);
   printByte(bb);
   delay(1000);
}
void loop() {
   showTTP229data();
}
// binary output function
void printByte (byte bytePrint) {
   for (unsigned int mask = 0x80; mask; mask >>= 1) {
      if (mask & bytePrint) {
         Serial.print('1');
      }
      else {
         Serial.print('0');
      }
   }
}

Load the sketch to the Node MCU ESP8266 Board, open the serial port monitor and view the keyboard status output using the 1-15 button (1-pressed, 0-pressed):

4. Script for determining the pressed key on the keyboard in python

The Arduino development environment is not the only way to program with ESP8266. Another option is microbion. Python Python 3, C C, which is optimized for microcontrollers.

Documentation for getting started with micropython for ESP8266 - https://docs.micropython.org/en/latest/esp8266/tutorial/intro.html

Let's write a script to detect the pressed keys on the touch keyboard and output them to the terminal. The contents of the script:

// import libraries
from machine import I2C, Pin
import time

data = bytearray(2)
/ / displays a list of keystrokes
def getkeys(data):
   arr=[0.15,14,13,12,11,10,9,8,7,6,5,4,3,2,1]
   str1="click "
   mask=0x0001
   for i in range(1,16):
      if (mask<<i) & data > 0:
         str1=str1+str(arr[i])+" "
   printf(str1)

i2c =I2C(scl=machine.Pin(2), sda=machine.Pin(0))
while True:
   // reading data from the Capacitive touch TTP229 I2C module
   data = i2c.readfrom(0x57,2)
   word=data[0]<<8 | data[1]
   if word !=0 :
      getkeys(word)
   time.sleep(0.5)

Load the script to the Node MCU ESP8266 Board, open the serial port terminal and view the output of the pressed keys:

5. Writing an RGB led strip color setup program using the Capacitive Touch Disc Pad keyboard.

As a usage example, let's create a project to set the RGB color of the led strip using the Capacitive Touch Disk Pad keyboard.

We will use the following components:

• WIFI NodeM ESP8266 (https://robotdyn.com/wifi-nodem-esp8266-32m-flash-ch340g.html) - 1;
• Keyboard Capacitive Touch Disk Pad – 1 ;
• 16 Keys Capacitive touch TTP229 I2C module – 1;
• Transistor Tip122 – 3 r;
• Resistor 1 kOm-3;
• Power supply unit 12V 2A-1;
• Wires.

6. Connection diagram

Component connection diagram:

7. Writing an RGB led strip color setup program using the Capacitive Touch Disc Pad keyboard.

Assigning buttons to the Capacitive Touch Disk Pad keyboard.

Define the purpose of the keyboard keys.

8. Writing a sketch in C (Arduino IDE)

Sketch for setting the color of the led strip in the C programming language for the Arduino IDE programming environment:

// connecting the library
#include "Wire.h"
#define TTP229_LSF 0x57

// contacts for connecting led rgb
int pwmRED=4;
int pwmGREEN=14;
int pwmBLUE=5;

// colors for led rgb
int colors[][3]={{0,0,0},{0,0,0},
{100,0,0},{100,100,0},{0,100,0},
{0,100,100},{0,0,100},{100,0,100},
{255,0,255},{255,0,0},{255,255,0},
{0,255,0},{0,255,255},{0,0,255},
{60,60,60},{150,150,150}};

void setup() {
   // start I2C
   Wire.begin(0,2);
   // operation mode of led rgb - OUTPUT connection contacts
   pinMode(pwmRED, OUTPUT);
   pinMode(pwmGREEN,OUTPUT);
   pinMode(pwmBLUE,OUTPUT);
   // turn off led rgb
   analogWrite(pwmRED,0);
   analogWrite(pwmGREEN,0);
   analogWrite(pwmBLUE,0);
}
// receive data on I2C
void getTTP229data(byte *a, byte *b) {
   // request 2 bytes from TTP229
   Wire.requestFrom(TTP229_LSF, 2);
   int dataN = 0;
   while(Wire.available())
      {
      // getting bitwise
      char c = Wire.read();
      if (dataN == 0) *a = c;
      if (dataN == 1) *b = c;
      dataN++;
      }
}
/ / determining the number of the pressed key
int getKey()
{
   byte aa,bb = 0;
   unsigned int mask=0x01;
   int key=0;
   getTTP229data(&aa,&bb);

   for(int i=0;i<8;i++) {
      if(((mask<<i) & aa) > 0) {
         key=8-i;
         i=8;
      }
   }
   for(int i=0;i<8;i++) {
      if(((mask<<i) & bb) > 0) {
         key=16-i;
         i=8;
      }
   }
   return key;
}

void loop() {
   int k=getKey();
   if(k>0) {
      analogWrite(pwmRED,colors[k][0]);
      analogWrite(pwmGREEN,colors[k][1]);
      analogWrite(pwmBLUE,colors[k][2]);
   }
   delay(500);
}

Upload the sketch to the Node MCU ESP8266 Board and check the program operation

9. Writing a Python script

Script for setting the color of the led strip in the python programming language:

// importing libraries
from machine import I2C, Pin, PWM
import time

/ / creating objects
i2c =I2C(scl=machine. Pin(2), sda=machine. Pin(0))
pwmRED=PWM (Pin (4))
pwmGREEN=PWM(Pin (14))
pwmBLUE=PWM (Pin (5))
data = bytearray(2)

/ / returns the number of the pressed key
def getkeys(data):
   arr=[0.15,14,13,12,11,10,9,8,7,6,5,4,3,2,1]
   str1="click "
   mask=0x0001
   for i in range(1,16):
      if (mask<<i) & data > 0:
         print("i=",arr[i])
         return arr[i]

// setting pwm values for RGB
def setRGB(key):
   colors=[[0,0,0],[0,0,0],
      [512,0,0],[512,512,0],[0,512,0],
      [0,512,512],[0,0,512],[512,0,512],
      [1023,0,1023],[1023,0,0],[1023,1023,0],
      [0,1023,0],[0,1023,1023],[0,0,1023],
      [200,200,200], [500,500,500]]
   pwmRED.duty(colors[key][0])
   pwmGREEN.duty(colors[key][1])
   pwmBLUE.duty(colors[key][2])
   
while True:
   data = i2c.readfrom(0x57,2)
   word=data[0]<<8 | data[1]
   if word !=0 :
      k=getkeys(word)
      setRGB(k)
   time.sleep(0.5)

Upload the script to the Board and check the program operation.