Cost effective door/window sensors (UK)

[JDRoberts]

Any sensor which relies on a magnet is likely to eventually have problems if the magnet is placed on a metal surface. It’s just physics. Eventually the metal near the magnet also becomes magnetized and then the sensor will have difficulty.

See the following thread which discusses some of the options:

Ecolink door sensor won't work around metal

I installed an Ecolink door sensor on my wrought iron gate. The magnet is on the gate and the sensor is on the 1.5" square post. It worked for about two weeks and then stopped working. I went out to troubleshoot it and found that when I remove it from the gate, and move the magnet over it several times, it begins to work again. I can “open/close” the sensor without any issues at all. The moment I put it back up against the gate, it stops working and it remains in whatever state it was at when I placed it against the metal. I have tried so many variations to this process that I am convinced it is the gate metal that causing the problem. The weird thing is that it worked perfectly for the first couple of weeks. I have tried taking a 1/4" piece of wood and using it as a backing for the senso…