Auto-ranging ohmmeter using Arduino.

This article is a few straightforward motorcars go meter victimization, Arduino. The measured resistance is showed employing a 16×2 liquid crystal display. The circuit is sufficiently correct and uses the minimum variety of external elements attainable. Before going into the main points of this project, allow us to have a glance at the essential resistance activity methodology.

We find it tough to scan color codes on resistors to seek out its resistance. so as to beat the issue of finding the resistance price, we have a tendency to square measure aiming to build an easy Ohm Meter victimization Arduino. the essential principle behind this project may be a potential divider Network. the worth of the unknown resistance is showed on 16*2 liquid crystal display. This project conjointly is 16*2 {lcd|liquid crystal show LCD digital display alphanumeric display} display interfacing with Arduino.

Concept of Resistance Color Code:

To identify the value of the resistance we can use the below formula.

R= { (AB*10c)Ω  ± T% }

Where

           A = Value of the color in the first band.

           B = Value of the color in the second band.

           C = Value of the color in the third band.

           T = Value of the color in the fourth band.

The table below shows the color code of resistors.

Color

Value

Black (2nd and 3rd bands only)

0

Brown

1

Red

2

Orange

3

Yellow

4

Green

5

Blue

6

Violet

7

Grey

8

White

9

Resistance = AB x C ± D%

Where,

A’ represents the 1st digit, that is that the 1st Band color of resistance.

B’ represents the 2nd digit, that is that the 2nd Band color of resistance.

C’ represents the 3rd significant figure, that is that the 3rd band color of resistance and this can be the number price. 

D’ represents the 4th figure, that is that the 4th Band color of the electrical device and this can be the tolerance worth.
Name 4 Band Resistor

Description

A 1st Band Color  1st  significant digit
B 2nd  Band Color  2nd  significant digit
C 3rd  Band Color Multiplier
D 4th   Band Color Tolerance

To make it more convenient here is the Resistance Color Code Calculator where you only need to enter the color of rings on the resistor and you will get the resistance value.

Circuit Schematics

The circuit is actually straightforward. All you would like is Associate in Nursing Arduino, the electrical device you wish to live, and another electrical device with a well-known worth. We’ll come upon a resistance with the well-known and unknown resistors, and live the voltage between them with the Arduino. Then we’ll run a program which will calculate the resistance from Ohm’s Law.

HOW ACCURATE IS IT?

These are the readings I got with a 200 Ohm “unknown” resistor:

 

Components needed for this Project

You can get the components from any of the sites below:

*Please note: These are affiliate links. I may make a commission if you buy the components through these links. I would appreciate your support in this way!

You can watch the following video or read the written tutorial below.