Digital 15-Kilogram Weighing Scale
Created: Sep 17, 2014
No description available.
Weighing scale is a measuring device to figure out the weight or mass of an object being tested. There are many types of weighing scale; they differ in construction, materials used and sizes depending on its usage. This project is a strain gauge scale; an electronic version of spring scale, and the deflection of its beam supporting the unknown weight are measured using a strain gauge, which is a length-sensitive electrical resistance. The resistance of the strain gauge beam to its deflection limits the measuring capacity of this project.
A 15kg weighing scale was designed using Microchip's TC500A analog processor. The TC500A is an analog processor device that performs a dual-slope analog-to-digital conversion function. All of the counting and timing for the conversion must be controlled by a microprocessor. The microprocessor is programmed to monitor the status and to control the timing of the TC500A. The 15kg strain gauge used for this application has an output of about 1mV/gram that gives a gain requirement of at least 50. The MCP606 CMOS operational amplifier is best suited for this because of its low noise and minimal drift. The output impedance of the strain gauge is only 300Ω so a single-ended configuration is more than adequate.
This design can be used in restaurants, bakeries, food manufacturing and other areas requiring fast operation and flexibility, of which it offers durability and precision in one economical design.