I have a shed that is only about 125 feet from my HA install, I have zigbee, z-wave standard and LR, and an RTL-SDR integrated for 433mHz sensors. My house was built in 1850 more or less so the walls do not pass signals well as they are lath and plaster construction.
I would like to find a sensor that indicates that my shed door is open or closed and it needs to send a closed signal, not just infer that the door has been closed. I would want it to be battery powered and have an indicator LED when it changes state if possible.
So, I have no way to extend my zigbee network or bluetooth proxy that far. Maybe could make an ESP with antenna get there reliably, but would have to be sure to keep it powered at all or most times for indication. Z-wave LR devices look like an option, but the prices are crazy for these devices. So, that brings me down to 433mHz which really looks like a good option in this case.
I am running SDR to Home Assistant and it has been pretty stable other than cheap SDR units run hot and need to be replaced every few years or they tend to drop and need the service restarted which I do with an automation. To this end, I would need a sensor that has been decoded within this addon. This is where I am stuck!
For our shed door, I have a reed switch connected to a Shelly Uni. Alternatively, use a reed switch connected to an ESP8266 or ESP32.
I just need to know if the door is closed so one reed switch. If you want to know fully open and fully closed (and neither, ie partially open) then use two reed switches connected to the one Uni/Esp.
I want to see the door open or not closed and I want to see closed. I assume that means the reed switch is closed when the door is closed and the switch is open when the door is not in range of the magnet. Am I making the right assumption?
My goal is to have an automation that logs when the door becomes not closed and one on a timer that tells me if the door is not closed at something like 15 minutes after sunset, means I maybe did not close it after working in the yard.
My default would be to use an 8266, but power is not always on in the shed. I do have a sonoff that I use to turn on and off my well pump for the yard in the shed and one for my bug light as well. The range is there on 2.4 ghz but there is not always power by the door.
I already run Hue, Sonoff zigbee, z-wave, an RTL-SDR and an esp32 with CC1101 to do rf transmits for lights and fans. The Sonoff gateway is really redundant in my house. I am really not wanting to add another hub to just watch a door. My Omada wifi on the 2.4 band does reach the shed, kinda weak but reliable. If I could locate an ESP near the door, I would throw one out there with Tasmota and be done with it.
The door sensor just has the magnet or the main sensor on the door and either the magnet or the sensor on the frame based on how you want to set it up (having the magnet on the door and the sensor on the frame lets you setup two sensors for say a gate system so you know when its fully open and fully closed).
Most cases will just do the former having the sensor on the door and the magnet on the frame so that when its closed it detects as closed.
Some go further to modify the case of the sensor so it's hidden in top of the door and the magnet is hidden in the frame just above it for a clean look.
You can do this with a single sensor setup, just attach it, set it up and setup the automation to do what you want via triggers and conditions.
You can have that with one reed switch at the door closed position (easy to arrange) & one at the door fully open position (might be harder to arrange). With our garage door, I have two reeds & one magnet. The magnet triggers the reeds at each position and if both are not triggered then the door is partially open. It doesn't really matter if the reed switch is NO or NC. Our shed has power which makes it easy - running on battery would be a pain. Solar charged 12V battery with a step-down voltage converter? Too many bits for my liking.
I also have an alert if the shed door is not closed an hour after sunset.
The distance is borderline for the more common network connection methodologies. You may have to go with LoRa as your more reliable error corrected network link if the above options do not work.
nRF24 is another lower cost option. NRF52840 chips may be useful as they are supported by ESPHome and you can easily connect the one or two reed switch sensors necessary to sense door position and lock status. Low power consumption too.