One of the things that triggered my “Weather Station” project was a request to build a similar Air Quality Sensor for a friend. This uses the same laser sensor, but a different computer board and temperature/humidity sensor. The kit is around £22 from Ebay.
The computer connects to the world via a WiFi connection (the aerial is that little squiggle on the bottom of the computer board) and you use a web browser to configure the system.
This sensor had to be a neat unit on a wall, and a bit of rummaging around on the internet found a suitable case for this system. Unfortunately, that design mounted the laser sensor “upside down”, which is not recommended by the manufacturer, so I ended up redesigning the internal frame:
I also had to design and 3D print a ‘tube’ to get the air from the outside world into the sensor – I could have used a plastic tube, but it’s difficult to get that much bend in it. And I didn’t have any…
The exhausted air from the sensor comes out at the bottom of the laser sensor, and can escape to the world via tiny holes in the base.
The top right hole in the computer board is used for a small cable tie to restrain the power cable.
The unit will be powered from a long USB lead, which goes through the mounting bracket into the case. Once the unit is installed, it will be connected to the terminal block on the right of this photo:
Once the unit settled down, they both gave very similar readings so I’m happy that everything works as planned.
You can see the readings from this sensor here: opensensemap.org/explore/60e478f616d878001b1df5f0 – You’ll need to click on the US flag on the top line and select English unless you want the text to be in German.
However, note that the sensor is currently disconnected, but should be up and running in a week or so. The sensor is also shown at the location where it will be eventually installed. The site does have useful descriptions of what PM10 and PM2.5 actually mean and there are plenty of other sensors to explore.