Close a small relay when Bluetooth connects

Hello Everyone, I need to close a 12 volts relay when a phone connects to that relay/board using Bluetooth. When i disconnect BT the relay should opens. No PC involve. Please point me in the right direction on how to accomplish that. Thank you. Andre

I have never tried this myself, but it should be possible using the built-in bluetooth of an ESP32 ( plugged into one of our 1-channel relay controllers (

The ESP32 would need to constantly loop through the connected bluetooth devices and react accordingly.

Thank you Jacob. I ordered one and try it.

Hello Jacob, I received the module. I powered it, the blue light is flashing but i tried with many iphones and I don’t see any BT network. I emailed the company twice at but i haven’t heard from them. Looks to me like a total scam. So don’t buy DSD TECH 12V Bluetooth Relay Module for Remote Control switch Compatible with iPhone and Android .
Any suggestions? Thank you. Andre

Well if you just need to control relays over bluetooth, that ESP32 module with our IoT interface relay controllers would work:

Keep in mind you’ll have to write software on the ESP32 to accept bluetooth connections and activate the relays.

We should have some libraries attached to each product with some Arduino code that should be compatible with the ESP32.