I'm trying to turn ON the LED(inbuilt/PIN13) when photoelectric proximity sensor(12v) senses any object. Sensor is connected on pin 2. Assigned pin 2 as INPUT, I've got a 12v spdt relay for switching. 12v output from sensor is fed to coil, on the other end 5v supplied to COM pin and "Normally Open"(NO) pin to Arduino (with pull-down resistor). When 'NO' connected to loose LED it works properly (shows 5V on voltmeter when object is detected). But when connected to Arduino digitalRead(), it always returns LOW/0.
//code int a=0; void setup() { pinMode(2,INPUT); pinMode(13,OUTPUT); Serial.begin(9600); }
void loop() {
a == digitalRead(2);
Serial.println(a);
if(a==HIGH){
Serial.println("Object Detected");
digitalWrite(13,HIGH);
}else{
Serial.println("There's no object");
digitalWrite(13,LOW);
}
delay(1000);
}