Also from the Arduino LoRa library API:
Just looking at your device versus the one listed in OpenMQTTGateway, these are two different devices.
@ wmaker
I am still confused of what I need to purchase due to the lack of knowledge of how LoRa works. I thought it was just the device I linked to on Aliexpress. But later found out that I also need a gateway device and a RA-01H chip which I will need to solder?
If you do decide to tackle this project, please update us with images. A PIR sensor was mentioned, but I never saw images of the sensor mounted on the device.
I noted that. The author never shows what he actually uses as the sensor, there are just pins left blank for that on the sender board. In one vide there is a pir sensor shown in his workshop and I guess that is what he uses. You could use a tilt sensor on the flap, or really any binary sensor.
The circuit that the author designed is a LoRa sender, it sends to LoRa messages to an openmqtt gateway, which is built on a LoRa equipped esp32. The author has a picture of how this works here
The esp32 is the LoRa to Wifi Bridge.
Now the sender unit has to be soldered, if you want to use that sender unit. Part of the soldering is a LoRa chip, in this case a RA-01. That comes in different versions to accommodate the different frequencies used internationally.
You could, instead of using the author’s sender unit, with soldering and all that, buy a lora device, which should (if you choose the right one) have a battery charger and battery cover built in. There are examples on ali I am sure. Trouble is, most LoRa devices that are connected to a MCU are connected to an esp32, which is not needed for the sensor and will consume more power than the arduino in the author’s board.
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Thanks for the detailed explanation. This is definitely not a project for the beginner. Soldering is one thing I do not want to do. I have asked the op if his boards are pre soldered and for sale, but it’s not.
As I say, look for a pre-soldered board. If you buy two of the LilyGo boards, all you have to do is solder a sensor on it.
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Yes, according to the silkscreen on the PCB as well as the schematics, its a AM312 PIR Sensor module.
Here is a little bit more info from what I have researched on the mailbox sensor side.
The OP is using a technique to save battery consumption by having the AM312 be the only major component that is powered continuously, and only powering the ArduinoProMini after motion is detected and its is powered only long enough for it to send a packet to the Gateway. The technique used, requires the removal of the regulator from the ArduinoProMini and replaces it with a regulator (that goes on his PCB) that has an “enable” pin, along with supporting circuitry. When enabled, this replacement regulator provides power to the Arduino. This enable pin can be driven by either the AM312’s motion active signal and/or the ArduinoProMini itself.
From what I can tell, the AM312’s motion active signal, when active, remains active for about 2 seconds as a minimum. Long enough for the Arduino to bootup and for it to drive its side of the regulator’s enable pin and thus keeps the Arduino powered until it has finished its task. Once finished, the Arduino releases its side of the enable signal, and likely by this time so has the AM312’s motion active signal released its side of the enable, which cuts off power to the Arduino.
There may be alternative ways to use an off-the-shelf ESP/LoRa and save power, but the OP’s technique looks pretty good.
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If I’d have looked that up I would have known that 
I’m just working on small projects that will allow using any off-the-shelf dev board with the same logic
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Hi all,
I wanted to put out some important info concerning different kinds of Arduino Pro Minis. You may be aware that there are 5V/16MHz versus 3.3V/8MHz versions (3.3V version needed for this project), I found out that there are also versions with the FTDI pins flipped.
As shown on the project’s GitHub page, make sure you get the version that has the FTDI VCC (at the bottom) that aligns with it.
Cheers.
I ended up getting an Arduino Pro Mini from Sparkfun.
It has the correct FTDI pin-out for use with the Mailbox Sensor PCB.
As an FYI, it also comes with SJ1 (Solder Joint).
SJ1 bridges the connection between the output of the board’s voltage regulator (and power “on” LED) to the board’s Vcc. With SJ1 for the mailbox sensor, instead of having to remove this regulator and LED, you can simply remove the solder joint (just use a soldering iron and some solder wick).
Hi. Were you able to got it all setup?
With SJ1 for the mailbox sensor, instead of having to remove this regulator and LED, you can simply remove the solder joint (just use a soldering iron and some solder wick).
Is this the joint (SJ1) to to remove?
Yes that is SJ1 as shown.
I finally completed this project a couple of weeks ago. I’ve changed the software some on both the sensor side and the OpenMQTT GW side, as well as 3D printed parts for use with my mailbox. I hope to do a write up in a few more weeks on it.
Hi, I’m not good at programming, that’s for sure! very interesting what you changed in GW.
I also have some progress.
I made a new version of the Mailbox sensor with an Integrated AS312 PIR sensor, read switch, and Battery charger. Which uses an Optional Li-Ion 14500 battery, the same size as “AA”, or you can use an even smaller lipo battery 200-300Ma.
If for you sensor size is more critical you can snap the charger part of the board and use it without a charger. The charger remains functional 
and the board becomes smaller “42x19” mm. But in this case, you can no longer use Li-Ion 14500 batteries.
Ps: Full board is “61x19” mm (smaller than a lighter)
Ordered prototype boards
I finally got around to doing a blog write up using the original version of the mailbox sensor in my project along with the changes I made to the sensor’s sketch code and the OMG code. The OMG code changes aren’t really required, but I have what I think is a LORA-WAN sensor in the neighborhood showing up from time to time so one of the changes was to help deal with it, Plus I added code to display text on the OLED display that came with the device that I choose as the Gateway.
The mailbox sensor sketch code was changed primarily to add a “node-id” and the messaging data was changed to use JSON.
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Thanks, very well explained 
Will you be releasing your 3D Printed Part for Lilygo TTGO for printing?
Sure, no problem. I placed 2 STL files for the Lilygo TTGO here. You can click on the STL files, and GitHub should render a 3D model that is viewable. I used a M3x16 screw to mount the “Base” to the wall, and M2x6 to mount the “Cap” to the “Base”.
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Hi, how about using something like this in P2P mode + spare I/O on NodeMCU board that we all have?
Hey everyone!
I’d like to share several projects related to mailbox notifications. I’ve prototyped three different versions, each using distinct architectures and technologies:
-
WiFi Devboard ESP32:
-
LoRaWAN Devboard (CubeCell-AB01):
- Designed for long-range communication, the CubeCell-AB01 is resistant to interference.
- It operates on low power, allowing the battery to last several months.
-
Adeunis LoRaWAN Smart Building Device:
- The Adeunis Dry Contacts is the best accomplished solution with complete integration with Home Assistant.
- The device ensures reliability and boasts an ultra-low power consumption, it can last up to 10 years on a single battery charge.
Feel free to explore these options and choose the one that best fits your mailbox notification needs!