I have been trying to count pulses from a 12,500 Hz square wave to trigger an output. Here's the code I have so far. When the Arduino is reset it prints 315 to the serial over a 25 ms sample. 315 x 40 = 12600. Which seems to me it's working perfectly.
My only problem is it only returns this number once upon reset of the board. Now if I move that same code down into void loop
, it counts consecutively giving me inconstant returns.
I am not understanding what I need to put in the loop section so I can repeatedly and accurately count how many toggles of the input pin I am getting over a period of time so I can do something to the output based off the presence of the 12,500 Hz signal or not.
volatile int IRQcount;
int pin = 2;
int pin_irq = 0; //IRQ that matches to pin 2
void setup() {
// Put your setup code here, to run once:
Serial.begin (9600);
attachInterrupt(pin_irq, IRQcounter, RISING);
delay(25);
detachInterrupt(pin);
Serial.print(F("Counted = "));
Serial.println(IRQcount);
}
void IRQcounter() {
IRQcount++;
}
void loop() {
// Put your main code here, to run repeatedly:
}
Using the above code, every time I press the reset button I get one line in the serial window.
Counted = 441
Counted = 442
Counted = 441
Counted = 441
Counted = 441
Now I want to get the same result, but repeating over and over. That way if the signal drops out I can trigger an output to turn off (LOW). When the signal is present the output will go high.
My attempt was to move the attach interrupt down into void loop
, so it would repeat. Here's what it looks like.
volatile int IRQcount;
int pin = 2;
int pin_irq = 0; //IRQ that matches to pin 2
void setup() {
// Put your setup code here, to run once:
Serial.begin (9600);
}
void IRQcounter() {
IRQcount++;
}
void loop() {
// Put your main code here, to run repeatedly:
attachInterrupt(pin_irq, IRQcounter, RISING);
delay(25);
detachInterrupt(pin);
Serial.print(F("Counted = "));
Serial.println(IRQcount);
}
The return I get is self-updating, but the "count" instead of starting from 0 each time starts from the previous count. So it gets larger and larger. I am looking to return a constant value that represents my 12500 Hz signal so that, and only that, will trigger my output.
Counted = 442
Counted = 886
Counted = 1330
Counted = 177
Counted = 2221
Counted = 2667
Counted = 3112
Counted = 3557
Counted = 4002
Counted = 4448
Counted = 4893
Counted = 5338
Counted = 5784
Counted = 6229
Counted = 6674
Counted = 7120
Counted = 7565
Counted = 8010
Counted = 8456
Counted = 8901
Counted = 9347
Counted = 9792
Counted = 10237
Counted = 10683
Counted = 11130
Counted = 11576
Counted = 12022
Counted = 12469
Counted = 12915
Counted = 13361
Counted = 13808
Counted = 14254
Counted = 14700
Counted = 15147
Counted = 15593
Counted = 16040
Counted = 16486
Counted = 16932
Counted = 17378
Counted = 17825
Counted = 18271
Counted = 18717
Counted = 19164
Counted = 19610
Counted = 20056
Counted = 20503
Counted = 20949
Counted = 21395
Counted = 21842
Counted = 22288
Counted = 22735
Counted = 23169
Counted = 23616
Counted = 24062
Counted = 24508
Counted = 24955
Counted = 25401
Counted = 25730
Counted = 25756
Counted = 26200
Counted = 26646
Counted = 27093
Counted = 27539
Counted = 27985
Counted = 28432
Counted = 28878
Counted = 29324
Counted = 29770
Counted = 30217
Counted = 30663
Counted = 31110
Counted = 31556
Counted = 32002
Counted = 32449
Counted = -32641
Counted = -32195
Counted = -31748
Counted = -31302
Counted = -30855
Counted = -30408
Counted = -29962
Counted = -29515
Counted = -29069
Counted = -28622