LoRa based air quality sensors powered by hybrid capacitors and solar.

Sensedge, an IoT design and solutions company, wanted to be able to run their Senstick Outdoor Air Quality Sensor for ten years with a small form factor, no access to mains power and minimal outside intervention or maintenance.

They designed their system using LoRaWAN which provides long range connectivity with low power consumption. A small 1 Watt solar panel charges ultra-hybrid capacitors which in turn provide a constant power supply for the sensors and communications module.

Air Quality Monitoring Goals

The Sensedge smart air quality sensor gathers real-time data and provides communities with insight on their air quality.

The first sensors were deployed in Novo Mesto, Slovenia with a goal of detecting small wood-burning furnaces that have an outsized impact on air quality. They worked collaboratively with the municipality of Novo mesto to pick specific locations in a neighborhood with a mix of residential units, a school, and an automotive factory.

The goal is to have citizens receive better insights into the air quality of their micro-environment and be able to engage with their community to find the reason for the pollution, make improvements, and get cleaner air faster.

Power System Designed to Extend Product Lifetime

Instead of using Lithium Ion cells, Sensedge chose a power architecture based on ultra hybrid capacitors. Because their system uses so little power, they could forego the additional capacity of a traditional rechargeable battery.

In exchange, they get much better long term performance in extreme environments. The capacitors are rated for as many as 500,000 cycles and have an operating range between -40 and 85 Celsius. That means the system can continue reporting on even the hottest and coldest days of the year.

During periods of low light, especially during the winter, the system can also adjust to conserve power. It will automatically reduce the measurement cycles and data transmission rates when the charge level drops below specified levels.

Next Steps for the Sensedge Outdoor Air Quality Sensor

In addition to deploying the Sensedge across additional municipalities, Sensedge is continuing to make improvements to the product. They are exploring the state-of-the-art MOX AirQuality sensors combined with the edge ML data processing to further improve data accuracy while decreasing power consumption.