The AirPi is a Raspberry Pi shield kit, capable of recording and uploading information about temperature, humidity, air pressure, light levels, UV levels, carbon monoxide, nitrogen dioxide and smoke level to the internet.
The AirPi can be very cheap - you can build a basic station for less than £50 (including the Raspberry Pi!) by only including the sensors you need.
From the ground up, we designed the software and hardware for the AirPi to be modular. This means that it is really easy to add any sensors you find to your AirPi.