Measuring the pulse widths of a RF433 signal

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1

I have a RF433 receiver connected to pin A0. The receiver receives signals from a proprietary thermo sensor. The connected sensor (XY-MK-5V) is powered by 3.3V from Arduino, since I get a lot of interference, if I connect it to 5V.

I first used this sketch to determine, that the receiver is receiving the sent signal. It works (the embedded led flickers when the signal is being received).

Now I want to measure the pulse widths of the incoming signal. I've read here, that this could be done in three ways:

  • by using the pulseIn() method
  • using the external interrupts on pin 2 or pin 3
  • using the pin change interrupts

I decided to use the third option, since it works on all pins and I have to use an analog one.

When I run the sketch below I get nothing. Could someone explain to me why?

#include <PinChangeInt.h>
 
#define MY_PIN A0 // we could choose any pin
 
volatile int pwm_value = 0;
volatile int prev_time = 0;
uint8_t latest_interrupted_pin;
 
void rising()
{
  latest_interrupted_pin=PCintPort::arduinoPin;
  PCintPort::attachInterrupt(latest_interrupted_pin, &falling, FALLING);
  prev_time = micros();
}
 
void falling() {
  latest_interrupted_pin=PCintPort::arduinoPin;
  PCintPort::attachInterrupt(latest_interrupted_pin, &rising, RISING);
  pwm_value = micros()-prev_time;
  Serial.println(pwm_value);
}
 
void setup() {
  pinMode(MY_PIN, INPUT); 
  digitalWrite(MY_PIN, HIGH);
  Serial.begin(9600);
  PCintPort::attachInterrupt(MY_PIN, &rising, RISING);
}
 
void loop() { }
2

You cannot print from within an interrupt. Do the printing in the main program.
Also, this won't work properly:

volatile int prev_time = 0;

prev_time must be declared volatile unsigned long.