Thin magnetic open/close sensor (elevator door sensor)

[JDRoberts]

@wenglish

I’m looking for an open/close sensor to detect an elevator door being opened.

The sensor would be line-of-sight about 15’ from my ST hub, so all the metal involved in the door and door frame would not cause problems for RF.

Coming in late here, but the metal of the door will be a problem overtime. Not because of getting signal through to the hub which is 15 feet away, but rather because the metal surrounding the sensor will become magnetized itself over time and this will confuse the sensor into thinking that it is closed when it is not.

You probably did this experiment in science class in elementary school at one point, where a piece of metal which is not originally a magnet becomes magnetized after prolonged contact with a magnet.

The same thing happens with open/close sensors which are mounted on metal if the sensor is normally in the closed position.

See the following thread:

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…