My professor got the analog pins to work! I was having trouble because I wanted 6 pins to be able to use "Twinkle Twinkle" as the song to teach - however....the sound shield uses up 5 or 6 pins and then the SD card uses up another 3 and I was left with only 4. I was struggling trying to do testing and to get the Analog pins to work but they just weren't working.
However, my professor just emailed me saying that she's gotten them to work!
It turns out that they are labeled Analog 14-19 and not 0 - 5. So A0 is actually A14!
Here is the code that my professor created to test them :
// Pin for the LED
int LEDPin = 13;
// Pin to connect to your drawing
int capSensePin = 14;
// This is how high the sensor needs to read in order
// to trigger a touch. You'll find this number
// by trial and error, or you could take readings at
// the start of the program to dynamically calculate this.
int touchedCutoff = 128;
void setup(){
Serial.begin(9600);
// Set up the LED
pinMode(LEDPin, OUTPUT);
digitalWrite(LEDPin, LOW);
}
void loop(){
// If the capacitive sensor reads above a certain threshold,
// turn on the LED
if (readCapacitivePin(capSensePin) > touchedCutoff) {
digitalWrite(LEDPin, HIGH);
}
else {
digitalWrite(LEDPin, LOW);
}
// Every 500 ms, print the value of the capacitive sensor
// if ( (millis() % 500) == 0){
Serial.print("Capacitive Sensor on Pin 2 reads: ");
Serial.println(readCapacitivePin(capSensePin));
// }
}
// readCapacitivePin
// Input: Arduino pin number
// Output: A number, from 0 to 17 expressing
// how much capacitance is on the pin
// When you touch the pin, or whatever you have
// attached to it, the number will get higher
// In order for this to work now,
// The pin should have a 1+Megaohm resistor pulling
// it up to +5v.
uint8_t readCapacitivePin(int pinToMeasure){
// This is how you declare a variable which
// will hold the PORT, PIN, and DDR registers
// on an AVR
volatile uint8_t* port;
volatile uint8_t* ddr;
volatile uint8_t* pin;
// Here we translate the input pin number from
// Arduino pin number to the AVR PORT, PIN, DDR,
// and which bit of those registers we care about.
byte bitmask;
if ((pinToMeasure >= 0) && (pinToMeasure <= 7)){
port = &PORTD;
ddr = &DDRD;
bitmask = 1 << pinToMeasure;
pin = &PIND;
}
if ((pinToMeasure > 7) && (pinToMeasure <= 13)){
port = &PORTB;
ddr = &DDRB;
bitmask = 1 << (pinToMeasure - 8);
pin = &PINB;
}
if ((pinToMeasure > 13) && (pinToMeasure <= 19)){
port = &PORTC;
ddr = &DDRC;
bitmask = 1 << (pinToMeasure - 14);
pin = &PINC;
}
// Discharge the pin first by setting it low and output
*port &= ~(bitmask);
*ddr |= bitmask;
delay(1);
// Make the pin an input WITHOUT the internal pull-up on
*ddr &= ~(bitmask);
// Now see how long the pin to get pulled up
int cycles = 16000;
for(int i = 0; i < cycles; i++){
if (*pin & bitmask){
cycles = i;
break;
}
}
// Discharge the pin again by setting it low and output
// It's important to leave the pins low if you want to
// be able to touch more than 1 sensor at a time - if
// the sensor is left pulled high, when you touch
// two sensors, your body will transfer the charge between
// sensors.
*port &= ~(bitmask);
*ddr |= bitmask;
return cycles;
}
However, my professor just emailed me saying that she's gotten them to work!
It turns out that they are labeled Analog 14-19 and not 0 - 5. So A0 is actually A14!
Here is the code that my professor created to test them :
// Pin for the LED
int LEDPin = 13;
// Pin to connect to your drawing
int capSensePin = 14;
// This is how high the sensor needs to read in order
// to trigger a touch. You'll find this number
// by trial and error, or you could take readings at
// the start of the program to dynamically calculate this.
int touchedCutoff = 128;
void setup(){
Serial.begin(9600);
// Set up the LED
pinMode(LEDPin, OUTPUT);
digitalWrite(LEDPin, LOW);
}
void loop(){
// If the capacitive sensor reads above a certain threshold,
// turn on the LED
if (readCapacitivePin(capSensePin) > touchedCutoff) {
digitalWrite(LEDPin, HIGH);
}
else {
digitalWrite(LEDPin, LOW);
}
// Every 500 ms, print the value of the capacitive sensor
// if ( (millis() % 500) == 0){
Serial.print("Capacitive Sensor on Pin 2 reads: ");
Serial.println(readCapacitivePin(capSensePin));
// }
}
// readCapacitivePin
// Input: Arduino pin number
// Output: A number, from 0 to 17 expressing
// how much capacitance is on the pin
// When you touch the pin, or whatever you have
// attached to it, the number will get higher
// In order for this to work now,
// The pin should have a 1+Megaohm resistor pulling
// it up to +5v.
uint8_t readCapacitivePin(int pinToMeasure){
// This is how you declare a variable which
// will hold the PORT, PIN, and DDR registers
// on an AVR
volatile uint8_t* port;
volatile uint8_t* ddr;
volatile uint8_t* pin;
// Here we translate the input pin number from
// Arduino pin number to the AVR PORT, PIN, DDR,
// and which bit of those registers we care about.
byte bitmask;
if ((pinToMeasure >= 0) && (pinToMeasure <= 7)){
port = &PORTD;
ddr = &DDRD;
bitmask = 1 << pinToMeasure;
pin = &PIND;
}
if ((pinToMeasure > 7) && (pinToMeasure <= 13)){
port = &PORTB;
ddr = &DDRB;
bitmask = 1 << (pinToMeasure - 8);
pin = &PINB;
}
if ((pinToMeasure > 13) && (pinToMeasure <= 19)){
port = &PORTC;
ddr = &DDRC;
bitmask = 1 << (pinToMeasure - 14);
pin = &PINC;
}
// Discharge the pin first by setting it low and output
*port &= ~(bitmask);
*ddr |= bitmask;
delay(1);
// Make the pin an input WITHOUT the internal pull-up on
*ddr &= ~(bitmask);
// Now see how long the pin to get pulled up
int cycles = 16000;
for(int i = 0; i < cycles; i++){
if (*pin & bitmask){
cycles = i;
break;
}
}
// Discharge the pin again by setting it low and output
// It's important to leave the pins low if you want to
// be able to touch more than 1 sensor at a time - if
// the sensor is left pulled high, when you touch
// two sensors, your body will transfer the charge between
// sensors.
*port &= ~(bitmask);
*ddr |= bitmask;
return cycles;
}