PARADe (PAR Acquisition Device). Design and production of a portable PAR radiation sensor device

Abstract

In a context of climate change and agricultural practices focused on the preservation of resources, it becomes essential to precisely follow the crop to bring about a rapid response to problems (stress, weeds and diseases, etc.). Plant growth is based on a bioenergetic process called photosynthesis, which is itself stimulated by photosynthetically active radiation (PAR). Combined with the microclimate, this parameter is considered as an essential parameter in prediction models. However, the costs or the complexity of commercial solutions (sensors/ data logger) could be an issue that can delay the understanding of some phenomena. The purpose of this article is to provide a low cost, miniaturized and innovative alternative. This article explains how to design, build and calibrate a device for measuring the amount of PAR radiation, named : PARADe (PAR Acquisition Device), by combining an affordable PAR sensor (SOLEM PAR / LE) and an open source development platform (ARDUINO).
The sensor voltage is recorded on the ARDUINO after amplification. The calibration is done by comparison with a robust acquisition chain composed of a certified PAR sensor (PQS1 PAR Quantum Sensor Kipp & Zonen) and a data logger (CR1000 Campbell Scientific). The results are presented and discussed. The system is operational, usable on all the expected PAR values. The reliability and validity of the data are compared to that of the existing system. In perspective, a smartphone, a digital tablet or a laptop could be the interface with the device via a Bluetooth or Wifi connection.