การพัฒนาอุปกรณ์วัดแรงแบบไร้สายสำหรับการขนส่งผลผลิตเกษตรโดยใช้เซนเซอร์วัดความโค้งงอ

Abstract

The aim of this study was to design and implement a wireless force measurement system for use during transportation of agricultural products. Two flex sensors, each measuring 55.37 mm in length and with a resistance ranging from 25 to 125 kΩ, were affixed to a spherical, flexible material. Voltage signals generated by the flex sensors were wirelessly transmitted via a NodeMCU ESP 8266 module for analysis and recording by a computer system. The diameters of the sphere at air pressures of 0.1, 0.2, and 0.3 bar were 82.80, 85.98, and 89.97 mm, respectively. The device enabled measurement of compressive forces up to 83.26, 92.07, and 121.38 N at these pressures, respectively. The testing process was divided into two parts: laboratory testing and force measurement during transportation. In laboratory testing, the wireless force-measurement device was placed inside a basket measuring 39 x 59 x 31.5 centimeters, along with cantaloupes. Compressive force, horizontal impact force, and vertical impact force were measured. It was found that the maximum force acting on the cantaloupes inside the basket was 56.89 N, caused by a vertical impact. The cantaloupes were stored for a 5-day period and exhibited bruising on the 3rd and 5th days of storage. For force measurement during transportation, the basket containing both the force-measuring device and cantaloupes was loaded onto a pickup truck and transported over paved and gravel roads. The maximum forces exerted on the products during transportation were 15.56 N on a paved road and 21.98 N on a gravel road. This research demonstrated the utility of the developed device for monitoring forces during the transportation of agricultural products.