The airQ Project

The airQ project was started to monitor the air in the surrounding area when the station was located in a town, now that we are in the country the readings will hopefully be very much lower than they were in the town !!

Measuring the air for gas content, contaminants and radiation particles can give us a good indication of the quality of the air. Radiation measurements are taken using the GM-10 Geiger Counter.

10th July 2011

The air monitoring station is built using a combination of gas sensors and a dust sensor, all based on the Arduino Hardware Prototyping platform.

Prototype 2 was a huge step forward to making this a production sensor array. The processor has been upgraded to the Arduino Mega board so there are many more input and output pins, as well as native serial. The LCD panel has been swapped for a 20x4 unit to display feedback and measurements, and the DS1307 RTC is now up and running too, awaiting a 3v battery backup though. The other major step is the support for MQTT to move readings around. The MQTT Libraries written by Nick O'Leary have been used to connect to our exisiting MQTT server and publishes a message as well as displaying the reading on the LCD. At the remote end, an adaptor will be written to sweep the MQ message into the backend database.

The system is based on a 5 min cycle, with a waiting period of 143 sec, a CO purge of 60 sec, and CO measure of 90 sec. The CO2 sensor is immediate reading, so is triggered at the last 11 sec of the 90 sec CO measurement phase, along with the Dust sensor. Output is via the LCD, XML via Serial and MQTT to a Mosquitto hub.

What we are measuring

CO - Carbon Monoxide Carbon monoxide is present after burning and is a major compnent of car exhaust fumes. This sensor reads the content of CO in the air at a preset sampling interval.

CO2 - Carbon Dioxide Carbon Dioxide is a greenhouse gas and is present in the air.

Particles caused by dust, dry soil pollen and other contaminants such as smoke. The Sharp sensor has the capability to detect these particles and in some cases what they are, e.g pollen, smoke, dust.

The airqualityegg project, which is looking at a similar air quality distributed sensor network, we hope to integrate with their backend systems to send data externally.