How To Make An Arduino Ohm Meter

Make An Arduino Ohm Meter

Building an Arduino ohm meter is an excellent method to learn about electronics, A/D conversion, and how to use the Arduino platform. It can also be an enjoyable project for someone who appreciates gardening or cultivating plants.

This article will address a few frequently asked queries about creating an Arduino ohm meter. We’ll offer some helpful pointers and recommendations on how to make your own Arduino ohm meter. Let’s get going!

An Arduino is what?An Arduino is what

An open-source, user-friendly electronics platform with a long history is called Arduino. Anyone who creates interactive projects is supposed to use them.

With it, what can you start? Honestly, anything. Anyone can use it because it is open-source and based on simple hardware and software.

Even kids! The environment is perceived by obtaining data from various sensors, enabling us to influence our surroundings by directing light motors.

An IDE can be used to operate the Arduino. To program this gadget to accomplish what we want, you can write, edit, and upload code using the software. This is practical and

It makes repairing anything that doesn’t work simple. Arduino is more straightforward to learn than other programming languages since it employs a streamlined version of C++.

We find it challenging to determine a resistor’s resistance to interpret color coding on resistors. We will use Arduino to create a straightforward Ohm meter to get around the challenge of determining the resistance value. A Voltage Divider Network serves as the project’s fundamental tenet. On a 16*2 LCD panel, the value of the unknown resistance is shown.

This project will make use of the Arduino Uno. Beginners who wish to create their electronics projects should use the Arduino Uno board. It is obvious why it contains a 16 MHz ceramic resonator, 14 digital pins, and six analog inputs. It also includes an ICSP header, reset button, and USB connection for connecting to a PC or other devices for added convenience.

LEDs, motors, and other external devices can all be connected to the pins on the Arduino board.

Sensors that output analog voltage signals, such as temperature sensors, flex sensors, etc., are read using analog pins. These pins have an “A” before the number on them. The first analog pin is A0, for instance, while the last is A15.

An external power supply and a USB cable from your computer can power an Arduino Uno board. If you want to use the power supply, it needs to be linked to the Arduino board via the power jack.

Arduino Ohm Meter ApplicationsArduino Ohm Meter Applications

There are several uses for an Arduino ohm meter. You can use it to determine the resistance of your circuit or how much current is passing through a particular component in a circuit. It can also be used to gauge a circuit’s voltage.


The most typical application of an Arduino ohm meter is for measuring the resistance of a circuit. You must attach the negative lead of the Arduino ohm meter to one end of the circuit and the positive information to the other end to accomplish this. The resistance can then be read from the Arduino ohm meter’s display.

To complete this job, we will build a gadget that measures an unknown resistance and shows the reading on a screen.

Step 1: What Are The Requirements For This Project?

  • Breadboard
  • Arduino UNO
  • 16×2 LCD display
  • Jumper wires
  • 10k potentiometer
  • 470ohm resistor
  • Resistors (one with an unknown value and one with a known value)

To observe the resistance value that we are measuring for this project, we will need an LCD. All connections are made using a breadboard. A variable resistor is made of a potentiometer. The unknown value resistor is combined with the known value resistor to form a voltage divider circuit, which is then used to gauge the resistance of the unknown resistor.

A voltage divider network is the project’s key innovation. A voltage divider network is produced when two resistors are linked in series across a voltage source. The voltage divider network’s output is calculated by multiplying the input voltage by the ratio of the two resistors.

To explain it quickly, a reference voltage will be produced using the known resistor, and a variable voltage will be produced using the unknown resistance. We can determine the value of the unknown resistor by measuring the voltages across both resistors.

Step 2: Circuit And Connections

Next, the Arduino needs to be connected to the breadboard. This is accomplished by using jumper wires to link the Arduino’s ground (GND) pin to one of the power rails on the breadboard. Next, attach the V5 pin to the other breadboard power line. Finally, join one of the breadboard’s rows to one of the Arduino’s digital pins (we used digital pin 13).

It is advised that you link the various components of the circuit using jumper wires of various colors. Keeping track of which wires are connected to which will be easier as a result. To make them more stable, you may also use alligator pins.

It’s time to attach the resistors now that your Arduino is connected to the breadboard. We must connect the two resistors in series to make this setup work. While the unknown resistor should be attached to the analog input with one end and a positive voltage source with the other, the known resistor should be connected to the ground and analog input pins.

The next step is to configure our 1602 LCD display. In order to do it, the LCD pin description is as follows:

LCD PIN 3———– Middle pin of the pot
LCD PIN 4———– D12 of Arduino
LCD PIN 6———– D11 of Arduino
LCD PIN 7———– NC
LCD PIN 8———– NC
LCD PIN 9———– NC
LCD PIN 10——— NC

LCD PIN 11——— D5 of Arduino
LCD PIN 12——— D4 of Arduino
LCD PIN 13——— D3 of Arduino
LCD PIN 14——— D2 of Arduino

You can continue wiring your circuit now that you have all your resources and know where each pin should go.

The potentiometer must be connected after the LCD has been connected. The middle pin of the potentiometer should be attached to one of the rows on the breadboard and grounded to the power source.

Time to start writing some code! Once your circuit is fully wired, use a USB cable to attach Arduino to your computer.

Step 3: Using An Arduino Ohm Meter To Calculate Resistance

After setting up your development environment, use a USB cord to link your Arduino board to your computer. You must install board drivers before connecting an Arduino board for the first time. After that, the IDE should recognize the board automatically, and you can now upload the code.

A straightforward voltage divider network like the one below can be used to describe how this resistance meter works.

R1 and R2’s voltage divider network produces the signal.

Vout = Vin * R2 / (R1 + R2 )

We may determine the value of R2 as a result of the equation above by

R2 = Vout * R1 / (Vin – Vout)

Where R1 = known resistance

R2 = Unknown resistance

Vin = voltage produced at the 5V pin of Arduino

Vout = voltage at R2 with respect to ground.

Remark: Although the users should replace it with the resistor value they have chosen, the known resistance (R1) value chosen is 470Ω.

Step 4: The Code

It is simple to get your results on LCD if you want to. All you have to do is enter the code below.

#include <LiquidCrystal.h>
//LiquidCrystal(rs, sc, d4, d5, d6, d7)

LiquidCrystal LCD(12, 11, 5, 4, 3, 2);
const int analog pin = 0;
int analogval = 0;
int vin = 5;
float buff = 0;
float vout = 0;
float R1 = 0;
float R2 = 470;
void setup() {
     lcd.begin(16, 2);
void loop() {
analogval = analogRead(analogPin);
     if (analogval) {
          buff = analogval * vin;
          vout = (buff) / 1024.0;
       if (vout > 0.9) {
              buff = (vin / vout) – 1;
              R1 = R2 * buff;
              lcd.setCursor(0, 0);
              lcd.print(”  -Resistance-“);
              lcd.setCursor(0, 1);
            if ((R1) > 999) {
                   lcd.print(”   “);

                   lcd.print(R1 / 1000);
                   lcd.print(“K ohm”);
              else {
                   lcd.print(”    “);
                   lcd.print(” ohm”);
          else {
              lcd.setCursor(0, 0);
              lcd.print(” ! Put Resistor”);
              lcd.setCursor(0, 1);

Step 5: How The Code Functions

This code is straightforward and only uses Arduino IDE’s built-in features. We have interacted with an LCD display using the LiquidCrystal library. Many predefined commands, such as LCD.begin(), LCD.setCursor(), and LCD.print, are already present in the library ().

We have also utilized the wire library for I2C communication. This enables us to link our Arduino board with the LCD display using two wires (SDA and SCL).

Instruct the Arduino to wait one second before restarting the loop using delay(1000).

According to the LCD, our display is 02 rows and 16 columns wide. We employed begin(16,02) in the void setup (). These settings should be changed if you have a different LCD panel.

Final Thoughts

An excellent tool for designing interactive electronics projects is Arduino. It’s entertaining to experiment with, and you can also use it to create some pretty awesome stuff. Arduino ohm meters are one of those items.

In this post, we demonstrated how to use a few inexpensive components to build your own Arduino ohm meter, which can then be programmed to measure an unknown resistance and display the result on an LED screen. It’s up to you to exercise your creativity and create something fantastic!

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