A common sight in ‘smart homes’, door sensors allow you to detect whether a door is closed or open, enabling the triggering of specific events. Unfortunately, most solutions for these sensors are relatively bulky and hard to miss, making them a bit of a eyesore. This was the case for [Dillan Stock] as well, who decided that he could definitely have a smart home, yet not have warts sticking out on every single doorframe and door. There’s also a video version of the linked blog post.
These door sensors tend to be very simple devices, usually just a magnet and a reed relay, the latter signaling a status change to the wireless transmitter or transceiver. Although [Dillan] had come across recessed door sensors before, like a Z-wave-based unit from Aeotec, this was a very poorly designed product with serious reliability issues.
That’s when [Dillan] realized that he could simply take the PCB from one of the Aqara T1 door sensors that he already had and stuff them into a similar 20 mm diameter form factor as that dodgy sensor unit. Basically this just stuffs the magnet and PCB from an existing wart-style sensor into a recessed form factor, making it a very straightforward hack, that only requires printing the housings for the Aqara T1 sensor and some intimate time between the door and a drill.
Hmmm
Could a battery-less energy harvesting door open sensor be made? The magent swiping motion can be used to generate power using a well placed coil. It would make sense to generate the power from the door swing itself, and then have a small BLE or whatever radio transmit a few packets, then turn off when the power is exhausted.
It still doesn’t tell me if the door is actually locked or not. Basically the same as any wireless alarm contact transmitter. I feel an urge to yawn.
Use a smart lock for that. This is for useful for doors inside the house.
You are thinking too narrowly. These are useful for detecting a break in on external doors. I use them on internal doors as well (I have a multi level house). I use it to assist in automations like lighting and HVAC controls (if one of the doors in my house is left open in the winter the basement HVAC cooks the loft area).
Why do you want internal doors to be locked? That’s what this is for.
Why would it be limited to that? External doors are much more interesting to monitor. O, and you could train an AI model on the lock audio to determine if it’s locked or not. I am guessing this could work well, especially in combination with the door open/close sensor data.
Maybe a more hidden solution would be to put it on the hinge side of the door, assuming there is still enough of a gap to sense when the door is open.
It gets hard to tell if the door is open if it is at the hinge side. You could put it near the bottom or on top of the door for better concealment.
I may install this on my garage door so I could quickly tell if it’s open or closed by looking at the app. I could also write a script to remind me if the door is open at bedtime.
I always thought that’s what windows are for…. But seriously, I had the same need in the past for a basement door I regularly almost close but then forget to really close….