I need to design relay circuit which will be triggered by the optocoupler

Thread Starter


Joined Aug 22, 2022
Hello there!

I am searching for the components of garage door opening system.
I have a optocoupler on a IOT device which cannot be directly connected to the contacts on the garage door system.
I need a relay circuit which will be triggered by the IOT device optocouple and here are the specs:

- requires pull-up resistor and external power supply (10mA / max. 50V DC - no AC)
- Output may be loaded with max. 50mA

I am thinking of 12V supply and 34mW coil power relay, but I am not sure if it. Is there a better solution?

Thank you for your time and answers!

Jon Chandler

Joined Jun 12, 2008
Relay modules like the one pictured are cheaper than you can buy parts. They include either a driver transistor or optocoupler so they draw very little current from their's port pin to operate.

Caution: a quick search shows some similar modules without the driver transistor or optocoupler. Look for it in the description for the driver and a part on the circuit board with three or legs.