A group of students from Carnegie-Mellon university have devised an almost artistic method of displaying the levels of pollution in the air using large helium-filled balloons. Their method for doing so is extraordinarily simple, and the results are outstanding.
The electronics required to measure air quality is simple – in this case they’ve used the popular PICAXE microcontrollers that each read the results from a particular type of air quality sensor, such as a diesel-exhaust sensor. The PICAXE converts the results from the sensor into a colour by controlling a powerful RGB LED – so red is bad, yellow is OK, green is good, etc. After making the circuit portable by powering them with a rechargeable lithium-ion battery, they are then tied to the neck of a large balloon. When reaching the area of use, the balloons are inflated with helium – and allowed to rise into the air. (Don’t forget to attach a line to the balloon if you want it back).
As more people are interested in the quality of their environment, a project such as this is a fun and illuminating method of visualising the quality of air around them. The circuitry also lends itself to other purposes with the right sensors – for example displaying temperature, humidity, noise levels and other environmental factors. Using a row of balloons one could have an avante-garde form of weather station! Nevertheless, head over to the instructions site for all the plans, code and schematic here: http://www.instructables.com/id/Air-quality-balloons/?ALLSTEPS