The Mailbox Beacon is a device that detects when a new letter or package has been delivered to your mailbox using a reed switch. It sends a signal to your LoRa gateway, then the gateway sends a message via WiFi to MQTT server. It's designed to integrate with HomeAssistant, but can theoretically work with anything that supports MQTT based sensors.
- Microcontroller: Attiny1616
- Radio module: SX1278 LoRa 433 Mhz (Ai-Thinker-Ra-01)
- Sensor: Reed switch
- Voltage regulator: SPX3819M5-L-3-3
- Programming Protocol: UPDI
- Power consumption: in microamps range when asleep
- Gateway: LILYGO TTGO LoRa32 V2.1
- Status LED
Reed switch (or any other kind of contact switch) must be connected either to PA4 or PA7 pins and to the GND. Pins have internal pull-ups enabled and are "active low", so the switch must pull the pin to the ground when circuit is closed. Both pins have interrupts attached, microcontroller will send a message to the gateway when the logic level changes.
TEST button also has an interrupt attached and can be used to test the setup.
Power LED has a jumper that can be cut to reduce the power consumption.
The beacon sends the battery voltage (in milivolts) in every LoRa packet, so that you know when you need to re-charge the battery.
