Around the world in 80 Microamps - ESP32 and LoRa for low-power IoT
Learn how to design and deploy battery powered IoT sensors that can go years between charges. You could be forgiven for thinking (as I did) that the proliferation of wireless IoT solutions means that implementing environmental monitoring is a simple process. Typically, everything goes swimmingly for the first two hours until your battery runs flat. Many wireless development boards (even the ones with built in battery chargers) are actually not well suited to ultra-low-power applications. Being truly wireless means (shock) no wires, not even for power. So we rely on battery, and perhaps solar. This brings a host of challenges: selecting the right battery, avoiding power-hungry components, coping with the limitations of a low-power radio platform like LoRa, learning the intricacies of deep-sleep modes, and choosing and using solar cells. This is a case-study and lessons-learned from a real project for IoT utility metering. What seemed like a simple problem led to a deep dive into ultra-low-power subsystems of modern IoT processors, and the practicalities of the LoRa radio platform.