Relay pin acts differently with load - arduino

Question

I have the following code.
void setup(){
pinMode(14, OUTPUT);
digitalWrite(14, HIGH); //Relay
}
void loop(){
if (!digitalRead(14)){
digitalWrite(10,HIGH); //LED
digitalWrite(11,LOW); //LED
}else{
digitalWrite(10, LOW);
digitalWrite(11, HIGH);
}
}
In another portion of the code the relay pin changes states and I'm monitoring that with the digitalRead portion in the loop in hopes of changing which led is on based on the state.
Now the hard part. All of that works, except when I wire the relay to a magnet. This is all for a very intricate door control system with maglocks. And for some reason with the maglock hooked up to the relay the Arduino behaves very differently. It slows to a crawl once the relay is changed. Up until then all is fine, but as soon as the relay is activated, something causes it to slow way down.
What I can't figure out is why all is fine and relay triggers without side affects, until a load is attached to it.
Any ideas? Or a better way of monitoring a relay state? (Without storing its pseudo value in a variable)

Answer 1

You set the pin 14 as OUTPUT, but you're trying to read from it with digitalRead.
What you want to know is the value of the register that stores the value of the port.
You could go the easy way and use an auxiliar variable that stores the pin state like this:
bool state = true;
void setup(){
pinMode(14, OUTPUT);
digitalWrite(14, state); //Relay
}
void loop(){
if (!state){
digitalWrite(10,HIGH); //LED
digitalWrite(11,LOW); //LED
}else{
digitalWrite(10, LOW);
digitalWrite(11, HIGH);
}
}
And edit the rest of the code accordingly so state changes accordingly.
The 'Hardest to understand' solution, is to read the register value. since you're using pin 14 (the same as pin A0) you have to look into the port C According to the Arduino Reference on port manipulation (Link at the end of my answer).
So you can just do this:
void setup(){
pinMode(14, OUTPUT);
digitalWrite(14, HIGH); //Relay
}
void loop(){
if (!BitRead(PORTC,0)){ //Reads bit 0 of the register of PORTC (wich is the state of pin14)
digitalWrite(10,HIGH); //LED
digitalWrite(11,LOW); //LED
}else{
digitalWrite(10, LOW);
digitalWrite(11, HIGH);
}
}
This solution is more elegant and is exactly what you need. It might be harder to come up with so if you don't remember this in the future you could always use the "state" variable method.
Reference Bit Read Operation and Arduino Reference on port manipulation for more information.