Establishment of an Environmental Measurement Node Using Open Source Hardware

Abstract

We developed an environmental measurement node that complies with application communication protocol version 1.00-E10 of the Ubiquitous Environmental Controlling System (UECS). The node consists of an Arduino Ethernet board with a newly developed electronic interface for the sensors in the measurement environment. A temperature and humidity sensor, a CO₂ sensor, and a solar cell (as photosynthesis photon flux sensor) were connected to it for testing. Software that we developed to operate it made it easy to change settings and adapt sensors. The node was installed in a plant factory with sunlight and connected to a UECS via a LAN. The apparatus operated as a UECS node, formatting the measurement values in accordance with the UECS protocol. Measured values of air temperature, humidity, and CO₂ concentration had estimated maximum errors of 1.17°C, 4.14%, and 49µmol mol^-1, respectively. These values (though not those of the light sensor) were accurate enough for practical use. The hardware design, software details, and UECS protocol are presented in full.