Recently, I embarked on a DIY project to create a low-power 433MHz temperature and humidity sensor, inspired by the Oregon Scientific THGN/THGR series. These sensors are known for their impressive battery life and reliability, but since they’re no longer manufactured, I decided to build my own clone. The goal was to replicate their functionality while ensuring compatibility with my existing Home Assistant setup.
The journey began with gathering the necessary components: an Arduino Pro Mini, a BME280 sensor, and a 433MHz transmitter module. The challenge was to design a system that could operate for years on two AA batteries. To achieve this, I focused on optimizing power consumption by utilizing sleep modes for both the MCU and the BME280 sensor.
After some research and experimentation, I managed to reduce the average power consumption to just 55µA, which translates to over five years of battery life. The sensor transmits data every five minutes, and the rest of the time, it sleeps to conserve power. The code was developed using the WlessOregonV2 library, which helped me reverse-engineer the Oregon Scientific transmission protocol.
The project was a huge success! The sensor integrates seamlessly with my Home Assistant setup, and I couldn’t be happier with the results. This experience not only taught me valuable lessons about low-power design but also reinforced the importance of community support in the smart home DIY space.
If anyone has similar projects or tips for optimizing battery life in IoT devices, I’d love to hear about them! Let’s continue to innovate and share our experiences to make our smart homes even smarter.