Instead of trouble each time you wish to search out the resistance of an electrical device, simply build Associate in Nursing Ohm meter and live all of your resistors. If you return up with a decent thanks to label and organize them, you’ll ne’er have to be compelled to pay time idea the distinction between those little gray and purple bands once more.


The circuit is sufficiently correct and uses the minimum sort of external parts getable. Before going into the most points of this project, permit the USA to own a look at the essential resistance activity methodology.

We find it robust to scan color codes on resistors to hunt out its resistance. therefore on beat the problem of finding the resistance value, we’ve got a bent to face live getting to build a simple Ohm Meter victimization Arduino. the essential principle behind this project is also a possible divider Network.

Required Parts :

  • Arduino Uno Board       [Purchase Links]         Ali-Express        Amazon
  • Project Board & Connecting Cable                    Ali-Express        Amazon
  • Resistor                                                              Ali-Express        Amazon

Connection :

The circuit is admittedly easy. All you would like is AN Arduino, the resistance you wish to live, and another resistance with a famous worth. We’ll create a resistor with the famous and unknown resistors, and live the voltage between them with the Arduino. Then we’ll run a program that may calculate the resistance from Ohm’s Law.


Enter the worth of your famous resistance (in Ohms) on line five of the code on top of. In my case, I’m employing a famous resistance with a worth of 1K Ohms (1000 Ohms).

The program sets up analog pin A0 to scan the voltage between the famous resistance and also the unknown resistance. you’ll be able to use the other analog pin although, simply amendment the PIN in line one, and wire the circuit consequently.

How Accurate Value it is?

That’s as a result of I used to be still employing a 1K Ohm well-known resistance. The accuracy of the Ohm meter is going to be poor if the worth of the well-known resistance is far smaller or larger than the resistance of the unknown resistance.


The problem is definitely mounted by employing a well-known resistance that’s nearer in price to the unknown resistance. Once I replaced the 1K Ohm well-known resistance with a 100K Ohm resistance, the accuracy of the measurements improved greatly.

These values are much more accurate, with an error of about 1.8%.

I just measured all of my resistors and wrote the resistance value on the paper strips holding them together. It’ a lot easier than looking at the color bands every time you need a certain resistor!

Arduino Code