Nanoceramic NiMn2O4 Powder-Based Resistance Thermometer for Soil Temperature Measurement Application

Abstract

The objective of this study is to construct a thermometer for soil temperature measurement application using sol-gel derived nanoceramic NiMn2O4 powder. The nanoceramic NiMn2O4 powder has been prepared using wet chemical method and characterized by FESEM/EDS and XRD. FESEM results confirmed its uniform morphology and the formation of the nanopowder. EDS confirmed that the powder consists of Ni, Mn, and O2. Based on the XRD analysis results and Scherrer’s formula the average crystallite size became 34nm. The powder then compressed in electrically insulator but thermally conductor tube manually to make the thermistor based thermometer. Two pieces of folded and rolled Aluminum foils as electrical contacts followed by two Aluminum lead wires were connected to the two opposite terminals of the tube. The thermometer is calibrated and characterized using LM35 IC temperature sensor integrated with Arduino Atmega328. The thermometer can measure a soil temperature up to 42℃. The embedded system for the thermometer is done using Arduino microcontroller and Arduino software with signal conditioning circuits. This is the first kind of thermometer which is based on nanomaterials for soil temperature measurement application in Agriculture. Keywords: NiMn2O4; nanoceramic powder; thermometer; thermistor; soil temperature; calibration Figure 1