Long-Range Z-Wave Mailbox Sensor for $89

So, like everyone else who have exhausted the “z-wave mailbox sensor” on google search and read through the multiple long smartthings community threads on this topic, I came up with the same conclusion that a pre-made z-wave solution doesn’t exist. Ok, there was that failed kickstarter that wanted an insane amount of money for a 1000ft range sensor, but that doesn’t count.

I read the countless stories on dealing with metal boxes and routing antenna wires outside the mailbox and trying to impossibly extend a z-wave network using something like the aeotec extender.

I’ll state upfront that I already owned the MAIL-1200 wireless chime and it worked beautifully. My thick locking Fortress Fort Knox mailbox is made of 1/4" thick steel and 3/16" thick steel flap doors and the wireless transmitter that comes with the Mail Chime has no problem reaching the buzzer base station in my stucco house; which, by the way, stucco houses utilize metal mesh around the outside for the stucco so signals don’t normally travel very far.

Every time the flap is opened the metal ball tilt sensor activates and the buzzer inside rings three times. There is a volume/on-off rotary dial on the receiver. After measuring the voltage across the buzzer at full loudness, I measured around 7v at it’s peak, just enough to activate the coil in the micro relay. It’s easy enough to desolder the buzzer if you don’t want the sound AND smartthings alerts. I removed mine completely and wired the relay (+/-) directly to the buzzer solder points on the circuit board. Oh one last thing, you need to solder or crimp a wire from the (S) pin on the relay board to the (+) terminal as well, since you want the incoming buzzer voltage to be the supply voltage to the relay board AND the signal that activates the relay to fire.

Once the coil gets activated, the relay switches from NC to NO, thereby closing the contact on the Window Open/Close sensor. This sends the Z-wave signal to the smartthings hub and Bam! You have a mailbox sensor.

I also own Sonos speakers around the house, so I also had Smartthings send me a text message that the “mail has arrived” and speak text over the Sonos speakers “your mail has arrived”. Since the buzzer makes 3 buzzes, I didn’t want that happening 3 times, so I set the custom monitoring alert to occur only ‘Once Per Day’ on ‘M,T,W,Th,Fri,Sat’.

The only thing I had to do was setup a new device type for the window open/close sensor because the Open and Close status were reversed. No problem, just search the forum for the “My Z-wave reversed window/door sensor”. I had the same issue with my aeotec dry contact sensor and it works beautifully. Simply reverses the state in the code.

Hope this helps anyone else who’s looking for this solution.


PARTS LIST (Amazon):

$43.95, Mail Chime MAIL-1200 Wireless Mail Alert System (Made by Hanna Products Inc.), ASIN# B00103FDDU
Amazon: http://a.co/14OFrcP

$5.80, Tolako 5v Relay Module for Arduino ARM PIC AVR MCU 5V Indicator Light LED 1 Channel Relay Module Works with Official Arduino Boards, ASIN# B00VRUAHLE
Amazon: http://a.co/hBCZA8O

$39.25, Z-Wave Door and Window Sensor with Nexia, RS 100, Both White and Brown Cases Included, ASIN# B008Q5CTBE



If anyone needs even more range, you could choose a Z wave plus contact sensor instead of a Z wave classic model. It would probably cost a little more, so there’s no reason to do it if you don’t need it. But you could likely get an extra 40 or 50 feet out of it if range was a big issue. :sunglasses:


Excellent post! I just bought the MAIL-1200. I have some questions:

  1. You mentioned:

“I removed mine completely and wired the relay (+/-) directly to the buzzer solder points on the circuit board.”

Regarding the two buzzer solder points - which one is + and which one is - ?

  1. Do the NO & C terminals from the relay connect to the Z-Wave device (or is it the NC & C)?


I dug out my old multimeter, and confirmed that the + buzzer solder point is the one that’s closest to the top edge (same side as volume control) of the MAIL-1200. I try to avoid battery operated Z-Wave devices if possible. So, instead of using a door/window sensor, I used a MimoLite. I connected the NO and C of the SRD-05VDC-SL-C to connect to the + and - (respectively) signal inputs of the MimoLite. Then, I reversed the open/close status of the MimoLite device. In addition to being a DC powered device, another advantage of the MimoLite is that it responds to status changes at most once per 10 seconds. So, when the MAIL-1200 buzzes 4 times when the mailbox is opened, the event associated with the MimoLite only triggers once (granted, only responding once can be done via software if needed, but no need to write special logic in software with the Mimolite’s behavior).

Thanks, Peter for your original post.

I know this is an old thread but it was very helpful.

I bought the Mail Chime to get an alert from my maibox that is in a direct line of sight 120 feet from my house. It worked great as long as I walked out and opened it but didn’t when the mailman delivers. The issue is my mailbox is on the opposite side of the road and when the mailman arrives his large vehicle blocks the signal. It doesn’t help that my mailbox is heavy aluminum.

I ended up moving the sending unit from inside the mailbox to outside mounted below on the pole. I opened the sending unit and replaced the ball\motion activated switch with a magnetic window\door sensor (https://www.amazon.com/30-10071-Spdt-n-c-Magnetic-Switch/dp/B00BMANPA4/ref=sr_1_12). The magnetic switch mounts on the inside of the mailbox door and a wire runs down to the sending unit on the pole. The switch makes contact and triggers the sending unit when the door is open.

Moving the sending unit outside the mailbox gives a stronger signal so the mail mans vehicle doesn’t affect the operation. Works every time.

I also modified the Mail Chime to interface with my HomeSeer Z-Wave system using the info in this blog.

I added the relay (https://www.amazon.com/Tolako-Arduino-Indicator-Channel-Official/dp/B00VRUAHLE/ref=sr_1_1_sspa) connected to the buzzer contacts inside the Mail Chime and a Z-Wave module (https://www.amazon.com/Wireless-Z-Wave-Multi-Input-Output-Contact/dp/B00B6RZ7MM/ref=sr_1_2). The Mail Chime now sends me an email and text each time mail arrives.

Thanks all for your input.

1 Like

I wanted to get a mailbox alarm that broadcast “You Have Mail” to the various Amazon Echo devices I have around the house. This was an excellent foundation, but I had to hack around a bit. First, the tilt switch didn’t work in the type of mailbox I have so I unsoldered it and ran wires to a NO magnetic reed switch. That worked, but only if the mailbox door was open (it’s the type of mailbox with both a slot and a keyed door). Since I couldn’t get a signal out of the heavy metal box, I added some wire and mounted the sending unit outside of the box. As suggested here, I added a relay to the base unit in place of the buzzer and used that to trigger a Raspberry Pi Zero. Then I used a bit of python glue code to trigger a virtual switch to drive smart things notifications using the Alexa Speaks skill. There were a couple of issues with that: the relay chattered so I ended up having to put a 1N4001 diode across it. Also, the Pi Zero occasionally got extra triggers so I had to put in some serious debouncing python code. I finally got all that working and it worked OK. In the end, I ended up bypassing the use of smartthings and used the Alexa API from the Pi Zero. Sadly, the Alexa API doesn’t allow me to play an audio clip so I can’t use the original AOL voice and the API doesn’t support multiple voices, etc. but it does broadcast “You have mail” throughout the house when the mail arrives, so I’m happy.