History of this Sensor Kit
The Wireless Sensor Network Kit documented in this repository is the third iteration. The previous versions were also Arduino-XBee-based sensor networks. However, all devices required a wall plug.
The first version of the sensor kit used Arduino UNOs together with XBee Shields and XBees as sensor nodes. The sensors were attached to the XBee shield. Router nodes consisted of an XBee, a power supply, and voltage regulator. The gateway consisted of an Arduino MEGA 2560 with an Ethernet shield and an XBee shield. The data was transmitted over HTTP to a web server. The sensor suite included DS18B20, SHT15, TSL2561, a SparkFun weather station, and pulse counters for oil flow meters and electricity meters. The sensor kit was deployed in a heritage building used as office space. Results with measured data from this sensor network can be found here: Balancing envelope and heating system parameters for zero emissions retrofit using building sensor data
In the second iteration of the sensor kit, a heat flux sensor and a pyranometer were added to the sensor suite. Further, the sensor module design was unified such that the sensor configuration could be changed on-site. The system was still based on Arduinos and XBees. However, a Raspberry Pi was used as gateway. A 3G-dongle enabled cellular network access. The enclosures for the sensor nodes and router nodes were 3D-printed. The sensor network was deployed in several apartments, a residential building, and an office building. All devices were still wall-powered. Experience revealed, that the Raspberry Pi and it's SD-card filesystem were not reliable. SD card corruption would happen often, which necessitated a on-site visit and caused a lot of data loss. Measures to address the issue, such as higher quality SD cards and read-only configuration of the SD card did not solve the issue completely. Results with measured data from this sensor network can be found here: Towards data-driven building retrofit
The third (and current) version of the sensor kit addressed the gateway issues of version 2, made sensor nodes battery-powered, and made the sensor configuration completely flexible. The system is still based on Arduino and XBee. However, this time the PCBs were custom designed and the firmware was written within the Arduino IDE. The initial gateway setup based on the Adafruit FONA Feather exhibited similar issues as the Raspberry Pi solution. The second attempt with a gateway based on an Arduino MEGA 2560 and a FONA breakout board yielded reliable results. This version of the sensor kit was deployed in more than ten residential buildings, apartments, and office spaces. Results with measured data from this sensor network can be found here: