Homework Help: Building a weighing machine

1. Jan 12, 2013

pcsx22

Project: Weighing machine based on potentiometer
Principle: On changing the length of the wire current in the circuit will change which will change the deflection in the ammeter

Set up: On top of four or three spring(same spring constant) a board is attached so when a weight is kept on top of it, the spring will compress and Jockey/slider attached with the board will slide on the wire and length changes

Problem: the problem is that when a weight is kept on top of the board, the spring tries to bend and the distribution of the force is not uniform. So is there a way out so that the force of the springs will be uniformly distributed and the spring will not bend?

2. Jan 12, 2013

Simon Bridge

A linear-coil spring is usually more laterally stable on expansion rather than compression.
Replace board with basket - suspend basket from spring - put weights to be measured in basket.
There are many designs that do what you want with your equipment - eg. look at how a 2-pan Roverbal balance works (with those it does not matter where the weights are placed in the pan: how do they do that?)

Last edited: Jan 12, 2013