Looking for a strong magnetic door sensor

[minor obsidian]

I have a door that has a tendency to pop open, especially when it's windy. I'd like to not have to lock it to keep it closed, and I also wanted to put a sensor on it so I can turn off the climate devices if the door is left open long enough. Anyone recommend a magnetic door sensor that can hold firmly? I can go with two separate devices, but a more graceful solution would be sweet.

[topaz snow]

I'm not quite sure you are asking for the right thing

A sensor is something that measures, but holding a door closed is an action

If you are looking for a sensor, any will really do

If you are looking for ways to keep the door closedy without explicitly locking it, that sounds a lot like am installation issue that should be fixed by properly adjusting the door

Or if that isn't possible, automatic/spring loaded door closers also can significantly increase the force required to open a door

[orchid willow]

I would recommend using a 'adjustable roller ball door catch' to hold the door closed. If the wind is quite strong you should look at a heavy duty version.

As for monitoring if the door is open, this is easily done with an ESP32 or ESP8266 and a reed switch. Although there are several readily available battery powered door sensors if you do not fancy the DIY route.

[minor obsidian]

I am looking for a battery powered door sensor. I was hoping that the strength of the magnets could help keep the door closed. You might think it's an installation issue, but for uninteresting reasons that's not a viable approach. I don't much like the look of spring loaded door closers, but they are an option as are the roller ball things -- it just seemed like an opportunity to solve two problems at once.

[burnt sentinel]

Hi Jack,
Magnetic door sensors does not exert any reasonably measurable force. On the contrary they're designed to be quite weak to detect small openings and to be more difficult to bypass. (Their main use is in burglary alarm systems)

So you wont find a magnetic sensor that actually holds the door - not by a long shot. The sensors sole purpose will be to let you know if the counterpart (the door) "disappeared".

I think, for your use case, there should be better options, but one thing you could consider that seems close to your line of thought is a mag-lock or magnetic lock.

They consist of a piece of metal you place on the door and an electromagnet. They exist in fail-safe and fail-secure which denotes their state when no power is applied (unlocked or locked when no power essentially).

The reason these might appeal to you is that you buy them in varying increments of force, typically rated in N (Newtons). This is typically used to ensure the door (lock) will be able to remain closed in the face of whatever it may reasonably be subjected to, but in your case, you could obt for a deliberately weak lock, that could hold the door closed with some reasonable force by be overcome by a determined push.

So for your rather special use case of holding the door "locked" against the wind (which the door hardware seems unable to do), but not actually wanting to lock the door, something like a mag-lock maybe even combined with a wind sensor or a weather integration could be a fairly automatic solution. When off, the mag-lock poses no extra resistance, requires no operation, etc. So the rest of the time it wouldn't be something you'd notice practically. Astetically I cannot say, it obviously depends what your door and house looks like. But there's a suggestion, none the less, and also clarification that door sensors will not do the job.