It feels wrong to put this in the Share your Projects category because it’s so simple. I literally did nothing and it works so well.
I wanted to make a magnetic mount for my Aqara Temperature and Humidity sensors (WSDCGQ11LM) and found some examples of 3D printable backing plates that could contain a magnet. I also considered glueing the magnet to the back of the original backing plate. Don’t bother!
The CR2032 battery is close enough to the back of the enclosure that an 18x3mm rare earth neodymium magnet can have more than enough holding force to pin the sensor to a door frame. It’s even strong enough to hold the sensor to the steel framing around house window openings through all the plaster.
Just put tape or a sticker on the magnet to prevent it from scratching paint off your door frames or walls.
Note that I’ve found some research saying magnets have no effect on lithium batteries but it didn’t say which type of lithium battery. I also found some research saying magnets reduce battery life if they’re strong enough, but I didn’t find anything about how strong the magnet needs to be to have a noticeable effect.
After a while I started using these cheaper magnets from Aliexpress.
For the Aussies here, I started with these magnets from Bunnings.
This also works for ZG-204Z and ZG-204ZL motion sensors.
