Improvement of the Capacitive Grain Moisture Sensor

Abstract

Abstract.Moisture is one of the most important factors affecting grain quality in storage. The grain must be dried as soon as possible after harvesting to lower moisture to a standard level. It is difficult to obtain satisfactory measurement effect on precision in capacitive grain's moisture measurement due to many influencing factors, such as temperature, species and weight. The data confusion method of Radial Basis Function nerve network is adopted with improved hardware of the measurement system. Tests show that the precision in moisture measurement of wheat has been improved.

New Sensing Technologies for Grain Moisture

“…The safety zone, according to Figure 1, is at humidity below 14% and temperatures below 18 • C. High levels of grain moisture in the harvest can lead to heat, fermentation, spoilage and a low flowering rate. To ensure safe storage, the grain should be dried as soon as possible after harvest and kept at lower moisture levels [4]. Grain moisture content (MC) is one of the most important factors describing the logical activity of grains.…”

Enhanced moisture sensing properties of a nanostructured ZnO coated capacitive sensor

“…Furthermore, the essential properties of moisture sensors for their extensive use include low cost, high sensitivity, precision and good performance. 9 Amongst various moisture sensors, the capacitance measurement based sensor became most popular due to numerous merits such as being nondestructive, fast response time, small sampling volumes, higher accuracy and low cost. 10,11 In the case of food grains, the capacitance value depends upon many factors 9 and can be expressed using eqn (1)…”

“…Furthermore, the essential properties of moisture sensors for their extensive use include low cost, high sensitivity, precision and good performance. 9 Amongst various moisture sensors, the capacitance measurement based sensor became most popular due to numerous merits such as being non-destructive, fast response time, small sampling volumes, higher accuracy and low cost. 10,11 In the case of food grains, the capacitance value depends upon many factors 9 and can be expressed using eqn (1) where K 0 = ( ε 0 A )/ D with A as the area and D as the distance between the two electrodes, ε 0 is the dielectric constant of vacuum, M is the grain moisture, ε g is the dielectric constant of grains, ε w is the dielectric constant of water, ε a is the dielectric constant of the air between grains, γ g is the volume of grains and e is the rate of air gaps.…”

A Grain Moisture Detecting System Based on Capacitive Sensor

“…It is generally fast, easy to implement online testing. In an indirect measurement, because many factors affect the moisture content, so the design of the sensor should be given enough attention, so that the output signal can effectively reflect the water feature [6][7][8]. Capacitive method is one of an effective method of moisture testing.…”