It’s a safe assumption that many of us have an array of wireless gadgets scattered throughout our homes, ranging from garage door openers to wireless thermometers. Each of these devices appears to have its own method for encoding information and transmitting it, making all those specialized receivers seem redundant. Wouldn’t it be wonderful to utilize existing RF infrastructure to connect your wireless devices?
[Malte Pöggel] believes this, and this LoRa rain gauge is the outcome. The construction begins with an off-the-shelf rain transmitter, which can be easily acquired at a low cost as an accessory for a wireless weather station and comes fitted with an ISM band transmitter. The rain-collection funnel and tipping-bucket mechanism were entirely functional, and the space freed by the current circuit boards provided ample room for adjustments, not to mention a perfectly functional battery compartment. [Malte] employed an ATmega328P microcontroller to monitor the tipping of the bucket, either through the original reed switch or via Hall Effect or magnetoresistive sensors. An RFM95W LoRa module manages the connection to [Malte]’s LoRaWAN gateway, with an option to incorporate a barometric pressure and temperature sensor, either by attaching the BMP280 chip directly to the board or by integrating an inexpensive I2C module, for those who prefer to avoid SMD soldering.
[Malte] invested significant effort into energy optimization, and the results are evident. A pair of AA batteries is expected to last at least three years, with a range extending up to a kilometer—considerably more than what the original ISM connection could achieve. Although this could have been realized using a LoRa module and some jumper wires, it represents a fantastic opportunity to dip your toes into LoRa design. You could even fabricate your own tipping bucket collector and adjust the electronics if you desired.