Attracted by the cheap price and the promise of sample code I bought a Touch Shield For Arduino UNO R3 MEGA 2560 R3 Capacitive Touchpad 9 keypad 3x3 from here
I managed to find a similar product here
The only immediately obvious difference being my board does not have the 3 extra pins to extend the number of inputs from 9 to 12.
I have attached the example code for the sparkfun board below. When I attach my board and run the code it displays the "Ready ... " message (Line 40) but the interrupt pin (pin 2) does go LOW when a key is pressed. The code is set up to create an interrupt to do this (line 37). As a result the getNumber() function is not called (line 48) By manually forcing pin 2 to go LOW I can get the program to enter the getNumber() routine but obviously it wont detect a key press.
Has anyone got this shield to work or can you suggest what else I can try to find out how my board might differ from the sparkfun shield so I can amend the code accordingly.
I am new to Arduino but willing to learn.
// Match key inputs with electrode numbers
#define ONE 8
#define TWO 5
#define THREE 2
#define FOUR 7
#define FIVE 4
#define SIX 1
#define SEVEN 6
#define EIGHT 3
#define NINE 0
//extras (not connected to button)
#define ELE9 9
#define ELE10 10
#define ELE11 11
//interupt pin
int irqPin = 2; // D2
void setup()
{
//make sure the interrupt pin is an input and pulled high
pinMode(irqPin, INPUT);
digitalWrite(irqPin, HIGH);
//configure serial out
Serial.begin(9600);
// initalize I2C bus. Wiring lib not used.
i2cInit();
// initialize mpr121
mpr121QuickConfig();
// Create and interrupt to trigger when a button
// is hit, the IRQ pin goes low, and the function getNumber is run.
attachInterrupt(0,getNumber,LOW);
// prints 'Ready...' when you can start hitting numbers
Serial.println("Ready...");
}
void loop()
{
//You can put additional code here. The interrupt will run in the backgound.
}
void getNumber()
{
int touchNumber = 0;
uint16_t touchstatus;
char digits;
touchstatus = getTouchStatus();
for (int j=0; j<12; j++) // Check how many electrodes were pressed
{
if ((touchstatus & (1<<j)))
touchNumber++;
}
if (touchNumber == 1)
{
if (touchstatus & (1<<SEVEN))
{
digits = '7';
}
else if (touchstatus & (1<<FOUR))
{
digits = '4';
}
else if (touchstatus & (1<<ONE))
{
digits = '1';
}
else if (touchstatus & (1<<EIGHT))
{
digits = '8';
}
else if (touchstatus & (1<<FIVE))
{
digits = '5';
}
else if (touchstatus & (1<<TWO))
{
digits = '2';
}
else if (touchstatus & (1<<NINE))
{
digits = '9';
}
else if (touchstatus & (1<<SIX))
{
digits = '6';
}
else if (touchstatus & (1<<THREE))
{
digits = '3';
}
Serial.println(digits);
}
//do nothing if more than one button is pressed, or if all are released
else if (touchNumber == 0)
;
else
;
}
