Sure it’s great to know the dust concentration in major cities across the world. I’m sure it’s really useful for lots of people, right? But what if you could know how polluted your environment is right now, right around you?
Scientists of Karlsruhe Institute of Technology (KIT) are developing a sensor that can be connected easily to smartphones. The sensor uses the flashlight of the phone to scatter light and measure it back. The light is scattered by the minuscule dust particles floating around, the reflected light is measured. The brightness of the pixels serves as a measurement of dust concentration.
Computer scientist Matthias Budde who has developed the system as a member of the research group TECO of KIT’s Chair for Pervasive Computing, explains
Instead of the conventional infrared LED in the sensor, the flashlight of the smartphone emits light into the measurement area. This light is scattered by the possibly existing dust or smoke. The camera serves as a receptor and takes a picture representing the measurement result. The brightness of the pixels can then be converted into the dust concentration.
The idea might sound far-fetched, but a group of scientists can’t go wrong! These sensors are yet to be as precise as the large equipment seen at government environment offices, but this is sufficient for detecting coarse dust and smoke not for typical fine dust concentrations in the microgram range. The sensor attaches to the mobile phone via a magnet and the data collected can either be processed locally or sent to a computer system. Right now, it can measure dust concentrations of about one microgram per cubic meter.
The next step for scientists is to increase the sensitivity of the sensors. One option includes bundling the flashlight with the sensor by using hemispherical lenses. This proved to be a better alternative to the phone’s inbuilt flash, in the far smaller second prototype built by the scientists at KIT. Another hinderance in measuring light densities accurately lies with how our phones process images. Once a photo is shot by the phones camera, several algorithms are used to compress the image before displaying it to the user. Though this conventional method is useful in conserving data and aids in faster load times for a typical phone user, a lot of important information is lost in the process. Phones of the future will have better hardware and software and will be able to supply raw photo data. This promises to increase the accuracy of the measurement to such an extent that the sensor will be able to detect typical fine dust over the course of the next year.
In the future, users are to take part in drawing up a pollution map via participatory sensing. This means that once a user measures the dust concentration he will be able to upload it to the cloud with relevant location data. Once a lot of users get involved, a virtual map can be drawn out of the information that has been procured. This would also allow the accuracy of the measurements to be further enhanced since a large amount of data would be available for a small area. The data is then estimated and put up on the map.
Budde also tells us that a gamification system could be incorporated into the system. This way users would be motivated to measure more areas and upload the data to the cloud. There could be badges and levels for people who upload the most data, visit the most places and so on.