Simplifying AttachInterrupt Code with 21 sensors

Official Hardware Mega Due
1

So I have 21 reed switches that I need to know when they are LOW to detect when a panel has been hit. I declared the pin # using an array. All of the switches need to be attached to an interrupt so I went through one by one and declared each attachInterrupt and created a corresponding function to that attachInterrrupt.

const int reedpins[] = {22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42}

pinMode(reedpins[1], INPUT_PULLUP);

attachInterrupt(digitalPinToInterrupt(reedpins[1]), sensor1, FALLING);

void sensor1(){
Serial.write(63);
Serial.write(reedpins[1]);
}

The Serial.write(63) is just a number used to state incoming data from the arduino to the other arduino using Xbee communication.

My question is, if there is a way I can simplify this instead of copying and pasting the function 20 more times? Possibly using one function for all 21 sensors.

The switches are supposed to send their pin # so I know which switch was tripped and the receiving arduino will light an LED to display which switch was tripped. I thought about using the function to run through each sensor using a for loop and find which one is low but I only have a short amount of time for the pin is HIGH again (about 250ms), so I' am not sure if that will work effectively.

3

You could use Direct Port Manipulation, put all the switches on 3 ports, and Poll them every 100mS or so; then act when you get a result that is Not 0xFF for one of the bytes.

4

I would certainly try @CrossRoad's suggestion. But you have not told us what you are trying to acheive and a FOR loop with digitalRead() may be sufficient, and a great deal simpler.

The line Serial.write(reedpins[1]); just prints the number of the pin. You need digitalRead(reedpins[1]); to get the current status.

...R

5

So I am using and Arduino Due which allows me to use all digital pins on attachinterrupts.

@Robin2 basically I have 21 pins all reading HIGH at steady state. When one of the panels is tripped it will go low for a second but then come back to HIGH quickly. The reason I went with interrupts is because it would tell me exactly when I panel is tripped and the reason I did Serial.write(reedpin[1]) was to have it send which pin has been tripped to the other arduino. Thanks for the input though.