Design and Development of Nanomaterial Based Digital Electronic Thermometer Probe: From Material-Device

Abstract

Temperature is defined as the measure of the average kinetic energy of the particles in materials. It is a fundamental quantity which affects any object and process including industrial processes, electrical systems’ components, life and health of living things, agricultural soil, highways, buildings, dams, environment, etc. So, it should be properly quantified and controlled using highly accurate, precise, environmentally friendly, in-situ, low-power and inexpensive thermometers. There are many kinds of thermometers with the disadvantages of high power requirement, possession of poison sensing materials, high cost, inaccurate and imprecise. Here, we discuss the development of nanoceramic nickel manganate (NiMn₂O₄) thermistor powder based digital electronic thermometer probe. The nanomaterial was synthesized using acetates of Nickel (Ni) and Manganese (Mn) as precursor materials by using the solution route technique. The fabricated powder was characterized using field emission scanning electronic microscopy (FeSEM) and energy dispersive spectroscopy (EDS) for its morphology and composition respectively. Powder x-ray diffraction (XRD) was also used to determine the crystal structure and crystallite size of the sample. The sample is unformed in morphology, spinel in structure, 24 nm in average crystallite size and composed of Ni, Mn and O₂ in the proper ratio. The 0.35 gm of the powder was filled and pressed well in 2 mm diameter and 2 cm long cylindrical tube to fabricate and characterize the thermistor based thermometer. The resulting thermistor was characterized and calibrated using the Stein and Hart and the β-coefficient thermistor models. The embedded system for the thermometer was developed using atmega328 microprocessor-based microcontroller, a simple voltage divider electric circuit, stainless steel cylindrical tube and 3D printed package. The system was programmed using Arduino programming integrated development environment (Arduino IDE). The features of resulting thermometer are 4-digit precision, 0 ℃-70 ℃ range of temperature measurement, 5 V DC power supply requirement, contains environmental friendly chemicals and is highly accurate. It can be used primarily in agriculture. It can also be used in industry, medicine, automobile, environment, food processing, home automation, etc. Additionally, it can be the element of sensor nodes in wireless sensor networks (WSNs) and Internet of Things (IoT) technology in automation.