The wireless sensor kit presented on this project site is preceded by two iterations. The first iteration was completed before I joined the team. It used Arduino Unos and XBee shields. The sensors were directly soldered to the XBee shields. There were a few different sensor node configurations:

• Air temperature and relative humidity (SHT15)
• Air temperature, relative humidity, and luminosity (SHT15, TSL2561)
• Supply temperature and return temperature (of radiators) (DS18B20)
• Oil flow (pulses), supply temperature, return temperatures and (heating system) (DS18B20)
• Electricity consumption (pulses) (never worked properly)
• Weather station (never worked properly)

The gateway consisted of an Arduino Mega with an XBee shield and an Ethernet Shield for internet access. As a failover measure, the gateway was also equipped with an SD-card and real-time clock for offline logging. The measured data was sent from the sensor nodes to the gateway and from there to an online MySQL database. Although the communication was wireless, all components still relied on cables for power.

Router nodes, which bridged larger distances between sensor nodes and gateway, consisted of an Xbee, which was powered by a mains adapter.

This sensor network was prototyped in a few weeks, deployed in a mixed-use building in Switzerland, and delivered live measurement data. The results can be found here: https://www.sciencedirect.com/science/article/pii/S0306261914006060

Because all sensor nodes and router nodes relied on mains adapter, there was a lot of cable management that needed to be done during installation. Another downside was that for every sensor combination a new Arduino shield needed to be designed.

In summary:

• The sensor network was developed very fast.
• Live measurement data could be collected.
• Limitations: Cables, selection of sensors, relies on on-site internet access

Source: https://www.sciencedirect.com/science/article/pii/S0306261914006060