The 3rd Version of OpenAirMonitor — Measuring Particulates, Humidity and Temperature in UK with Wio-E5 and Seeed Fusion

WHO estimates that 7 premature million deaths are caused by the effects of air pollution every year

New Global Air Quality Guidelines (AQGs), launched by WHO, aims to save millions of lives from air pollution. Since WHO’s last update in 2005, there has been a marked increase in evidence showing how air pollution affects health. In response, WHO has adjusted downward almost all of the AQGs levels and warns that exceeding the new AQG levels poses significant health risks.

Gerrit Niezen, a maker from the United Kingdom, realized the seriousness of the environmental problem early on and built 3 versions in total of his solar-powered outdoor air quality monitor that transmits air quality data over LoRaWAN and Bluetooth. This article introduces the 3rd version of OpenAirMonitor he designed.

Transmitting air data using Wio-E5!

There are some great open-source low-cost air quality monitors, but both the DIY and commercial varieties usually have the following shortcomings:

• Need to be connected to a power source
• Transmit data over WiFi, which is not available everywhere
• Sensor is less accurate at high humidity

For that reason, Gerrit decided to built an air quality monitor that can be

• Battery-powered and can be charged with a solar panel
• Use long-range wireless communication
• Easily expandable with other sensors

LoRaWAN® is a great alternative when electronics projects need long range communication but have no access to WiFi. It’s a proprietary, low-power and long-range wireless technology that uses license-free wireless spectrum. Gerrit chose Seeed Wio-E5 as the LoRaWAN® module. Seeed’s Fusion PCB assembly service also helped him to manufacture both the second and third revisions of the hardware. Talking about the Wio-E5 module’s role in the overall project, he indicated that:

The Wio-E5 (previously called the LoRa-E5) is used to communicate with LoRaWAN networks like The Things Network and Helium. It’s based on the STML32WL chipset, which includes both a microcontroller and a LoRa radio on the same chip! You can run your own software on the microcontroller, but it comes preinstalled with the LoRaWAN stack so you can use it as a LoRaWAN module. That means you connect to it from another microcontroller over a UART interface, and just send AT commands (e.g. AT+JOIN to join a network) to connect to a LoRaWAN network. I’m using the nRF52832 chip from Nordic as the main microcontroller, as it can easily be programmed with Espruino over Bluetooth!

The 3rd version is launched!

What is the difference between this latest version of the open-sourced air quality monitor and the previous version?

The third revision changes the main processor module from the MDBT42Q module that’s hard to get hold of at the moment, to an E73-2G4M04S1B that Seeed Fusion was able to source. Both modules use the Nordic nRF52832 chip internally. I also changed the 3.3V regulator to one that’s in stock. The global electronic component shortage is still very much with us in 2022.

It took Gerrit more than two years to build three revisions of the hardware before he finally made it. The enclosure design was the most challenging, given that it had to be weatherproof. The most recent version even encloses the antenna to remove any openings where water may get in.

The third revision changes the main processor module from the MDBT42Q module that’s hard to get a hold of at the moment, to E73-2G4M04S1B that Seeed Fusion was able to source. Both modules use the Nordic nRF52832 chip internally, which runs Espruino.

As for connectivity, at first he attempted to use The Things Network, but there were no existing gateways in the area. Even though he installed two himself, this still didn’t provide the coverage needed. So Gerrit used Helium, which has enough coverage at the places his air quality monitors installed.

There seems to be daily peaks around 9am and then again around 8-10pm. WHO air quality guidelines state that PM10 should be below 45 µg/m³ on average in a 24-hour period, so it seems to be the case.

“Seeed Fusion is such a reliable and convenient one-stop prototype service that I’d love to work with them again.” Said Gerrit.

During the free Design for Assembly check by Seeed Fusion PCB Assembly engineers, we found a mismatching footprint that was not discovered during the first prototype run, and where parts were out of stock we also worked with Gerrit to find suitable alternatives.

To accelerate the development of IoT industry to the next level, Seeed is sponsoring Wio-E5 projects 100% with the Seeed Fusion PCB Assembly Service for all hardware enthusiasts, designers, makers, and engineers around the world! Good ideas need to be discovered, and good projects deserve to be recognized, realized and widely disseminated! Each person is limited to two PCBA boards 100% completely FREE for one design, including PCB fabrication, the cost of parts, assembly and shipping. The design must include Wio-E5.

Furthermore, choose all your parts from Open Parts Libraries (OPL) and reduce the lead time to as little as 7 working days. Meanwhile, if you have mass production requirements, we highly recommend taking advantage of the Seeed Fusion PCB Assembly service and get the Wio-E5 modules for only US$5.90 (40% discount, original price US$9.90).

Take advantage of free prototypes and discounted modules with Seeed Fusion PCBA service now!

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