Citizen Science Air Quality – problems with one of our sensors

As discussed in previous posts we have received our 2 PM sensors – AirBeams –  and the first steps in our process are about setting them up and then testing the sensors as preparation before we engage with potential volunteers.

Unfortunately we’ve hit a problem. One of our sensors (and we’ve only got two!) has a problem. This didn’t appear straight away. Both sensors were generating readings in line with expectations and all seemed fine. However one of them (unit #1) seemed to have a problem with its power. It would work fine when connected to the mains supply, but stopped working on battery.

At this stage the AirBeam simply wasn’t powering up at all without a power connection. Our supplier – HabitatMap – have been great and offered excellent support. Together we began investigations to figure out what was going wrong and how to fix it.

Here’s a photo of the opened up AirBeam. The temperature and humidity sensor is the upright white “thing”, the particulate sensor is on the other side of the board to the left.

ab1

The final stage of stripping the AirBeam is shown below. This allowed us to get access to the battery. We swapped the existing battery (not shown here) with another battery we had in and sure enough the unit powered up. You can see the red light showing the unit running off battery power.

ab2

So we knew there was some fault with power, but was it a faulty battery or a problem with charging?

The photo below shows us charging up the existing AirBeam battery. If the battery wouldn’t take a charge for some reason, then we could focus in here and get a replacement battery swapped in.

ab3

When the battery was fully charged we put it back into the AirBeam, reassembled everything and did further tests. These tests led us to the conclusion that the battery is fine, but there is a problem with the charging mechanism in the AirBeam. Therefore we are sending this unit back for replacement or repair. HabitatMap have been great and will reimburse our postal costs.

So we are left with only one PM sensor for now. Our guess is 2-3 weeks for a new one to arrive, but let’s wait and see.

Although it’s frustrating, this was the point of the testing phase. Things do go wrong with technology and it’s better to pick these things up now, than impact the experience with volunteers. This technology is still pretty new!

Leave a Reply

Your email address will not be published. Required fields are marked *