PLOTS guys propose an interesting way to measure the quality of the air for indoor environments, by hacking a second-hand Roomba robot (an autonomous vacuum cleaner).
These robots are programmed to randomly move inside rooms to clean up the floor, so by adding a simple air quality sensor on top of one of them, it is possible to easily implement a sort of “random walker” that will sense for us the presence of gases (volatile organic chemicals, VOCs), such as NH3, alcohol, CO2 and so forth.
To keep track of the air quality measurements, the authors equipped the so hacked Roomba with an RGB led, whose color can be changed according to the air sample. By taking a long exposure picture of the room where the robot was roaming in, they could determine the areas where a high concentration of VOCs was present.
The complete description of the project can be found on the PLOTS’ website, while here you may find a short video about it:
PLOTS guys are also working on a different approach to air sensing, which does not make use of a Roomba robot but uses a hamster ball, instead. Further details can be found here.