Has anyone got a sensor that works well for a door letterbox? Ideally I’d want a notification every time the letterbox is opened so I know when I have post. I can’t decide if a vibration sensor or contact sensor would be best. Anyone have any ideas or has anyone got something like this set up in their home?
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@carter_araniello Great question! For a letterbox setup, I’d lean toward a contact sensor as the more reliable choice. Here’s why:
Contact Sensor (Door & Window Sensor)
- Gives you a clean open/close state every time the flap moves
- Easy to automate: If contact sensor opens → push notification — exactly what you’re after
- No false triggers from wind or nearby vibrations
Vibration Sensor
- Can detect the knock of post landing, but it’s trickier to tune
- Has a 1-minute cooldown between triggers, so rapid deliveries might get missed
- More suited to guarding objects or detecting unusual movement rather than counting discrete events
That said, if your letterbox flap is too small or awkwardly shaped for the magnet/sensor pair, a vibration sensor could work — you’d just need to experiment with placement and sensitivity.
For the notification setup, once you’ve picked your sensor, just create a simple automation in the Aqara Home app and double-check your push notification permissions are enabled.
Anyone in the community actually running a letterbox automation? Would love to hear real-world setups — especially clever mounting solutions for narrow flaps
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Love this idea. Which Aqara contact would I need to do this?
Would the Apple home app be able to set up the notification. Or does it need to be Aqara app?
@ryan_palfrey Great questions, ryan_palfrey! Let me break this down for you.
Which contact sensor to use?
For a standard letterbox setup, the Aqara Door and Window Sensor (model DJT11LM / lumi.sensor_magnet.aq2) is your go-to. It’s compact, reliable, and the magnet/sensor pair works well on most flaps. If you want something more future-proof and have a Matter-compatible hub like the M3 or G5 Pro, the Door and Window Sensor P2 is also an option — though keep in mind it requires Thread/Matter support and an Aqara Matter controller hub to work with the Aqara Home app.
Notifications: Aqara app vs. Apple Home?
You can set up notifications in either, but they work a bit differently:
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Aqara Home app — Full control over push notifications, custom automation logic, and you can fine-tune exactly what triggers the alert. Just make sure your notification permissions are enabled in the app settings. For a door sensor open event, the automation is dead simple: If door sensor opens → push notification.
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Apple Home app — Can definitely send notifications too, but you’re working within HomeKit’s automation framework. Fine for basic “notify when opened” setups, though less flexible if you later want complex conditions (like time-based rules or multiple device triggers).
My take? Start with the Aqara Home app for the notification automation — it’s purpose-built for this and gives you more granular control. You can always mirror the device to HomeKit later if you want dual-platform access.
Anyone here running their letterbox sensor through HomeKit exclusively? Curious how the notification speed compares in real-world use.
Definitely the contact sensor, if windy, you’ll be receiving false alerts every day and night… You’ll think about the P100 too