How to build a low cost Bluetooth relay

Bluetooth iconMeanwhile there are lots of solutions for home automation in the market. However the most of them share one flaw – their price. But blessedly there is Youtube where you can find a video for each topic…

On Youtube I came across a clever tinkerer named Lou, who shows how you can build a low cost Bluetooth relay. I think this is really cool, because there are a many application areas. You could open your garage door, switch lights on and off or unlock an electric lock. To build up one of these Bluetooth relays you must not even be a technical genius, because the use of a soldering iron is sufficient. Knowledge in programming or microcontroller-technology isn’t necessary.

For the Bluetooth relay you need only one transistor and a Bluetooth headset from Samsung. (Although I think each other headset that beeps, when you pair it with a device, should also work.) For triggering the relay you can use a mobile phone, a pc with Bluetooth adapter or a smartphone.

The idea behind the relay is in equal shares easy as well as brilliant. When you pair the headset it will beep for one time.  Instead of using the signal to beep, you can modify the headset, so that the signal is used to trigger a switch instead of the inner speaker. How this looks like in reality, you can see in the following video.

I think there maybe is no solutions possible which is even cheaper and easier. What do you think about this idea and where would you use it? I’m curious about your ideas.

Best regards,


  1. Ranier Vivassays:

    Hi! thanks for this video, it is very interesting. What is the transistor used?

  2. I have already used it for my garage port.
    I¨m using tasker (android app) and my Pebble watch to control it.
    Other ideas is doorlock on my brother in laws Ford Mustang, rear luggage lock and a modified version to control ignition/starter.

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