by Michael Pigg
I wanted to be able to monitor temperatures in multiple locations in my house so that I could tell if changes made in the HVAC system were working or not. Although a commercial solution would be easiest to implement, I decided to build my own instead. I designed a simple wireless temperature sensor around a Digi XBee wireless module that would send temperature readings at regular intervals. The next step was to build software to interface with the wireless sensors and capture the data that they were sending. The interface software (called XBeeLib) uses Apache Mina as a major component to handle translation of packets to and from the wireless modules. The monitoring software (called pHomeNet) is a Java-based system running on the Apache Felix OSGi container. Observations from the sensors are recorded into a database (Apache Derby by default). Although the system is currently focused on recording temperature sensor data, it could easily be adapted to record data from other sensors or even to control devices based on sensor inputs. This presentation will delve into the hardware and software aspects of the system, although with more emphasis on the software and the role that packages such as Apache Felix and Apache Mina play in the system.
1st–4th June 2010