We have developed several sensor devices that communicate with Internet applications via LoRaWAN. LoRaWAN is a standards based (https://www.lora-alliance.org/), low power, wide area, wireless data network, which is well suited to linking battery operated sensor / actuator devices to the Internet. LoRaWAN makes use of a patented, wide band, frequency hopping, sub-GHz radio to achieve long range communications at low power and in noisy conditions.
The printed circuit boards in these devices are to our own design, incorporating a low power microcontroller (e.g. STM32L432), a LoRa radio module (e.g. NiceRF lora1276) and electronic circuitry to drive the sensors / actuators. The devices have been designed to operate for more than 5 years using a non-rechargeable, AA sized Lithium-ion battery.
Software (or rather firmware) is based on the Semtech/Stackforce, LoRaWAN reference stack, which we modify to implement specific applications (e.g. ultrasonic tank level monitor, smoke alarm) and to drive the selected sx1276 radio module with the required LoRaWAN frequency profile (dependent on country and subset of frequencies selected to operate within a country’s band).