Metal Mailbox monitoring (ZWave or Zigbee external antenna)

Hi there !

My mailbox is in the garden, about 10 meters only from my house :

In my house I have :

  • Good wifi network : 3 Unifi Wifi AP
  • Good ZWave network : 21 zwave modules acting as router
  • Good Zigbee network : powerfull and long-range coordinator and routers

Everything works perfectly. No radio interference.
However I cant get any module of either of the 3 wireless technologies working inside my mailbox, which is full metal. I can get a decent signal juste outside the mailbox however.

What would you recommend to monitor my mailbox ?
I’d like to avoid a vibration sensor outside of the box, not 100% reliable I think. So my first idea was to put a door contact sensor (or maybe 2!) in the box, and put the antenna outside. But I don’t know if this can be done easily either with zigbee ou zwave devices.
Any idea ? suggestion ? :slight_smile:


For my mailbox, I modified a NCZ-3011-HA with an external antenna. The antenna is simply a wire that is 1/2 wavelength long. The antenna pokes out a small hole I drilled in the bottom of the mailbox, although mine is the traditional US shape with a flag and not like yours. What part of your box opens when mail is delivered?

One peculiarity is that the metal box disturbs the magnetic field of the magnet used to trigger the sensor. So I can’t tell if the box is left open, but I always will get the transition of open to closed or vice versa.

My house is brick covered, about 100 feet away and the signal reaches inside the house just fine.

Thank you for your answer.

My mailbox has 2 opening possibilities :

  • The small horizontal upper opening for standard letters
  • The large front door for boxes
    I will probably need 2 sensors, but that’s not really a problem.

I don’t know the NYCE device you are using but I have a lot of spare Zigbee modules @home from Xiaomi, Sonoff, Konke, IKEA, Philips,…
I’ve never checked if it was easy/possible to put an external antenna on these…

Zigbee having the same wavelength than wifi 2.4GHz, it should be easy to find external wire&antenna. I just need to see how wire it properly instead of the included antenna.

I think I will try to inpect inside a few modules tonight and check what can be done. :slight_smile: