PricelessToolkit's MailboxGuard Watches for Activity Then Alerts You via Home Assistant or WhatsApp
Designed to monitor for deliveries, or more nefarious activities, this LoRa-connected guardian is a low-power wonder.
Pseudonymous maker "PricelessToolkit" has designed a solution for anyone who wishes it was easier to know whether there's something to retrieve from the mailbox — using a LoRa-connected sensor compatible with Home Assistant, MQTT, or instant-messaging systems for notification.
"The Mailbox Guard is a device that detects when a new letter or package has been delivered to your mailbox using a PIR [Passive Infrared] sensor and door reed switch," PricelessToolkit explains. "It can send a signal to your LoRa gateway, then the gateway sends a message via Wi-Fi to Home Assistant [or] MQTT or to WhatsApp allowing you to receive notifications directly into your phone. Or you can use it offline, the gateway display will show the number of letters received, battery status, and signal strength."
The Mailbox Guard hardware is based on a microchip ATtiny1616 microcontroller connected to an AI-Thinker Ra-01 LoRa transceiver with coil antenna. The passive infrared sensor can detect the motion of the mailbox door being opened or a package being passed in front of it, with the open of an on-board or external reed switch for a mechanical alternative.
The board's design also includes a battery carrier for a 14500-format lithium-ion cell, with an optional connector for an external lithium-polymer battery, and a USB Type-C charging board which can be removed if not required.
PricelessToolkit says the design offers a very low-power monitoring solution, with the PIR taking up just 11.3uA and the reed switch option as little as 280nA — while each transmission of an event takes increases power draw to just 65uA. These transmissions are received by an off-the-shelf LILYGO TTGO LoRa32 gateway board, which can be programmed to send them on to Home Assistant, or to send notifications via WhatsApp messages.
The project's design files and source code are available on PricelessToolkit's GitHub repository under the permissive BSD three-clause license; a kit of parts or a fully-assembled version can be purchased in the PricelessToolkit IoT Shop at €42 or €44 respectively (around $46 and $48 respectively), TTGO LoRa32 gateway not included.