Abstract

A frequency-based capacitance type grain probemoisture meter was developed, as a low-cost alternative tool foraccurate and rapid moisture content measurement of paddygrains in bags. The prototype unit consisted of a standard grainprobe; a 100-gram capacity test chamber; a grain selector panelfor overall control and measurement; and a handle for ease ofsampling. Calibration models between frequency and dry ovenmethod moisture contents were established and validated with arelatively high coefficient of determination (R2) of 0.94.Laboratory and actual field testing conducted between moisturecontent readings of grain probe moisture meter and standardreference oven method resulted to mean absolute error of 0.24.Likewise, field testing results conducted revealed a meanpercentage error of 3.9 percent, an indication of a highlyacceptable level of accuracy based on standards set by theNational Institute of Standard and Technology (NIST) andUnited States Department of Agriculture – Grain Inspection,Packers and Stockyards Administration (USDA-GIPSA). Initialfabrication cost of the prototype unit grain probe moisturemeter was approximately US$ 100.00 which is very competitivewith existing imported popular brands of grain moisture meterswith investment cost ranging from US$ 750.00 to aboveUS$ 4,000.00 The prototype unit grain probe moisture meterhas the advantage of simultaneously performing grain samplingand moisture content determination. Likewise, the grain probemeter can potentially save time and effort in moistureassessment and most importantly ensure the procurement ofquality grains, ease in MC monitoring of stocks during storageand MC validation before storage and milling.