Help with using a diy capacitive switch for an led strip

Projects Programming
1

I am creating a diy capacitive switch using aluminum foil that turns on/off led when the switch is touched slightly, and changes the brightness of the led when its touched and held. But it's just not working and I don't know where it has gone wrong. Can somebody tell me where it has gone wrong and provide me a solution for this?

int capSensePin = 3;  // pin connected to alunmium foil
int ledPin = 13;     
int touchedCutoff = 100;  
bool ledState = false;  
unsigned long touchStartTime = 0;  
int brightness = 0;  

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);  
  pinMode(capSensePin, INPUT);  
}

void loop() {
  if (readCapacitivePin(capSensePin) > touchedCutoff) {
    if (!ledState) {
      ledState = true;
      touchStartTime = millis();
    } else {
      unsigned long touchDuration = millis() - touchStartTime;
      if (touchDuration < 1000) {
        ledState = false;
        digitalWrite(ledPin, LOW);
      } else {
        brightness += 10;
        if (brightness > 255) {
          brightness = 0;
        }
        analogWrite(ledPin, brightness); 
        while (readCapacitivePin(capSensePin) > touchedCutoff) {
          delay(50);
        }
      }
    }
  } else {
    if (ledState) {
      unsigned long touchDuration = millis() - touchStartTime;
      if (touchDuration > 1000) {
        while (readCapacitivePin(capSensePin) <= touchedCutoff) {
          delay(50);
        }
      }
    }
  }
}

uint8_t readCapacitivePin(int pinToMeasure){

  volatile uint8_t* port;
  volatile uint8_t* ddr;
  volatile uint8_t* pin;

  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 - 13);
    pin = &PINC;
  }

  *port &= ~(bitmask);
  *ddr  |= bitmask;
  delay(0);
  
  *ddr &= ~(bitmask);

  int cycles = 16000;
  for(int i = 0; i < cycles; i++){
    if (*pin & bitmask){
      cycles = i;
      break;
    }
  }

  *port &= ~(bitmask);
  *ddr  |= bitmask;
  
  return cycles;
}
2

assigning a non-integer value to an int. What do you think might be the result?
Why not print out touchedCutoff to see what value the compiler assigned.

3

oh wait that was supposed to be a 100 - I've just fixed it

4

Well? Has the behaviour changed, and if so, how?
By the way, on this forum, modifying the OP is frowned upon, it often makes follow-on posts nonsensical.

5

My bad, didn't know that :frowning:
and it's still not working

6

That's a pretty unhelpful answer, really. Not working - What does it do, act as if it's pressed, only act as if it's pressed for a short time, ???

'Splain to me, where in your code do you actually measure a physical pin?

7 
*port &= ~(bitmask);
*ddr &= ~(bitmask);

Again, the code ChatGPT produced is not working because the program (ChatGPT) does not understand how to program a simple LED. Humans do. You could if you dumped ChatGPT and helped yourself to Arduino Built-in sketches.
https://docs.arduino.cc/built-in-examples/

But, to repeat, fading an LED using a button you will need:

  1. Detect a button press
  2. Add or Subtract from a PWM value.
  3. Light the LED with the PWM.
  4. Reverse direction at max and min
  5. Go to 1.

And... why did you start a separate topic with the same, failed, ChatGPT "program?"

1 Like
8

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