I am aiming to operate my automatic garage door using an Arduino pro mini, 3.3v.
The existing hard wired switch to “pulse” the garage door open/close operates on 5v. The switch grounds the signal wire to make it happen.
I am wondering if there is any issues in connecting the 5v signal wire to a digital pin, and then pulsing the output to low. I can see there are two potential approaches of doing this.
// in setup digitalWrite(PINx, HIGH); pinMode(PINx, OUTPUT) // when I need to pulse the door digitalWrite(PINx, LOW); delay(250); digitalWrite(PINx, HIGH);
// in setup pinMode(PINx, INPUT); digitalWrite(PINx, LOW); // when I need to pulse the door pinMode(PINx, OUTPUT); delay(250); pinMode(PINx, INPUT);
Some of the issues that may be encountered: • 5v going through 3.3v Arduino causes damage. • Too much current - I believe there are already resistors in the existing door circuitry but will measure the current passing through the switch to check. • Arduino grounds input during boot up, which could inadvertently open the door.
The alternatives would be to use either transistors or relays, however I am trying to avoid additional components if possible.