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 […]