Air Quality Surveillance for Whole Cities

Air quality is becoming a major issue these days, and not just for cities like Beijing and Los Angeles. It’s important for health, our environment, and our economy no matter where we live. To that end, [Radu] has been working on air quality monitors that will be widely deployed in order to give a high-resolution air quality picture, and he’s starting in his home city of Timisoara, Romania.

[Radu] built a similar device to measure background radiation (a 2014 Hackaday Prize Semifinalist), and another to measure air quality in several ways (a 2015 Hackaday Prize Finalist and a Best Product Finalist; winners will be announced next weekend). He is using the platforms as models for his new meter. The device will use a VOC air sensor and an optical dust sensor in a mobile unit connected to a car to gather data, and from that a heat map of air quality will be generated. There are also sensors for temperature, pressure, humidity, and background radiation. The backbone of the project is a smart phone which will upload the data to a server.

We’ve seen other air quality meters before as well, and even ones based around the Raspberry Pi,  but this one has a much broader range of data that it is acquiring. Its ability to be implemented as an array of sensors to gather data for an entire city is impressive as well. We can envision sensor networks installed on public transportation but to get to all parts of every neighborhood it would be interesting to team up with the Google Streetview Cars, Uber, or UPS.

Watch those VOCs! Open Source Air Quality Monitor

Ever consider monitoring the air quality of your home? With the cost of sensors coming way down, it’s becoming easier and easier to build devices to monitor pretty much anything and everything. [AirBoxLab] just released open-source designs of an all-in-one indoor air quality monitor, and it looks pretty fantastic.

Capable of monitoring Volatile Organic Compounds (VOCs), basic particulate matter, carbon dioxide, temperature and humidity, it takes care of the basic metrics to measure the air quality of a room.

Exploded CAD View

All of the files you’ll need are shared freely on their GitHub, including their CAD — but what’s really awesome is reading back through their blog on the design and manufacturing process as they took this from an idea to a full fledged open-source device.

Did we mention you can add your own sensors quite easily? Extra ports for both I2C and analog sensors are available, making it a rather attractive expandable home sensor hub.

To keep the costs down on their kits, [AirBoxLab] relied heavily on laser cutting as a form of rapid manufacturing without the need for expensive tooling. The team also used some 3D printed parts. Looking at the finished device, we have to say, we’re impressed. It would look at home next to a Nest or Amazon Echo. Alternatively if you want to mess around with individual sensors and a Raspberry Pi by yourself, you could always make one of these instead.

Air Wick Odor Detect teardown


[Hunter’s] wife came home from her latest extreme couponing session with a handful of free Air Wick Odor Detect air fresheners, and since they had so many of the things sitting around, he was compelled to take one apart to see what makes them tick.

The casing was secured with melted snap tabs which had to be cut, making disassembly a one-way street. Once opened, he found a trio of white label AA cells and an ARNIE COMPACT3 ISS.4 controller board, complete with an epoxy-sealed microcontroller. A similarly branded sensor board was attached to the controller, and he spotted a solenoid with a built-in nozzle for spraying air freshener as well.

The sensor board piqued his curiosity the most, and after some research he’s pretty sure that the Air Wick uses an Applied Sensor VOC air quality module to get the job done. The tiny sensor uses a special substrate containing electrodes, which measure the resistance of the sensing layer while it is heated to upwards of 400° C.  A change in resistance lets the air freshener know that it’s time to handle the odoriferous emanations floating about.

Thanks to [Hunter] for taking the time to tear the Air Wick down and letting us know what’s inside!