A LoRa rain gauge from the ground up

It’s fair to assume that most of us have a ton of wireless doo-dads around the house, from garage door remotes to wireless thermometers. Each of these devices seems to have its own idea of ​​how to encode and transmit data, and all of these dedicated receivers seem wasteful. Wouldn’t it be great to use existing RF infrastructure to connect your wireless devices?

(Malte Pöggel) is of this opinion and this LoRa rain gauge is the result. The setup begins with a commercially available rain transmitter, which can be found inexpensively as an accessory for a wireless weather station and is already equipped with an ISM band transmitter. The rain collection funnel and tilting scoop mechanism were perfectly usable and the space freed up by the existing circuit boards left plenty of room to play with, not to mention a perfectly usable battery compartment. (Malte) used an ATmega328P microcontroller to count blade tilts, either via the original reed switch or via Hall effect or magnetoresistive sensors. An RFM95W LoRa module takes care of the connection to (Malte’s) LoRaWAN gateway, and there is the option to add a barometric pressure and temperature sensor using either the BMP280 chip directly on the board or a cheap I2C module adds who don’t enjoy SMD soldering.

(Malte) has put a lot of work into performance optimization and it shows. A pair of AA batteries should last at least three years, and the range is up to one kilometer – far more than the original ISM connection could have managed. Of course this could have been achieved with a LoRa module and some jumper wires, but this seems like a fantastic way to get acquainted with LoRa design. You could even print your own tipping bin collector and modify the electronics if you wanted.