Weird behaviour with RF24 and arrays

Projects Programming
1

Hello everybody,

This is my first post so first of all, hello whoever is reading this ;D

Well my problem is this:

I've one sketch with NRF24L01 working fine, but the problem is
The emiter sketch is like this:

  //...more code there
  triggers[1] = analogRead(TRIGGER_LEFT);
  map_triggers[1] = map(triggers[1],0,674,0,1023); 
  if(map_triggers[1]!=map_old_triggers[1]){
     cValues[0] = TRIGGER_LEFT;
     cValues[1] = map_triggers[1];
     //sendControlValues(cValues);
     radio.write(cValues, sizeof(cValues));
     }
  map_old_triggers[1] = map_triggers[1];
  //...more code there

On receiver sketch simply this:

//...more code there
while(radio.available()){
    radio.read(&value, sizeof(value));
    Serial.print(" Pin=");
    Serial.print(value[0]);
    Serial.print(" Value=");
    Serial.println(value[1]);
  }
//...more code there

The sketches over here work perfectly, i receive both values of the array perfectly, but as I've to manage more triggers and joystick axes an add some sentences on each I prefer to do a function so i can send the arrays of several analogic sources, below it's the function:

void sendControlValues(int Values[2]){
  bool ok = radio.write(Values, sizeof(Values) );
  if (ok){
    Serial.print(" OK!");
  }
  else{
    Serial.println(" FAIL!");
  }
}

And now the problem, while on the first case (without the function) I'm receiving perfectly both array values (value[0] and value[1]) on the second case I'm only receiving value[0] correctly, value[1] it's always 0 on receiver!!!

Inside the sendControlValues() if I print value[0] and value[1] it's printing the required value, print what should be printed but anyway I'm receiving always 0 at value[1] of the receiver.

I don't understand what I'm doing wrong. Simple case works perfectly but just inside a function not... :sob:

Thanks for your help :-[

2

Look at sizeof(Values):

void sendControlValues(int Values[2]) {
  Serial.print(F("sizeof Values "));
  Serial.println(sizeof(Values));
}
int testArr[2];
void setup() {
  Serial.begin(115200);
  sendControlValues(testArr);
}
void loop() {}

sizeof Values 2
It returns the size of the pointer (this is passed to the routine), not the size of the array pointed to.

3

You are right!!!!

I've been googleing a while and I have read there is no "clean" way to get this work, so I decide to use a fixed and known size of value, in this case I use a value of "4" (bytes) and all works correctly

Thank you very much!!!

4

You could pass the length of the array in bytes to the function.
That would be the standard way to do it. :wink:

5

Yep I'll do that! thx