Project Hub /Test & Measurement Instrumentation/Multimeters, Voltmeters & Ammeters/Milli-Ohm Meter With 0.1 To 1-Ohm Range

Beginner

ARDUINO

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

Milli-Ohm Meter With 0.1 To 1-Ohm Range

An Arduino-based milli-ohm meter circuit designed to measure very low resistances ranging from 0.1 ohm to 1 ohm accurately.

Originally published on ElectronicsForU

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

Arduino UNO R3 Board (Compatible) – ATmega328P Microcontroller with USB Cable Rs. 999.00
2-Slot 18650 Holder with Protective Cover and On/Off Switch – Case Rs. 109.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: LCD (generic / unspecified)
Voltage Regulator IC (7805 / LM317 / 1117)
Custom PCB / PCB Fab
Header Pins / Terminals / Connectors
9V Battery + Snap
B

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How It Works

The Milli-Ohm Meter project centers around an Arduino Uno board configured to measure very low electrical resistances accurately within the 0.1 to 1-ohm range. Power is supplied to the circuit via a 9V battery or a 9V, 500mA adapter. To ensure the microcontroller receives a stable and reliable supply voltage, a MIC5219 low-dropout regulator (IC1) regulates the incoming power down to the required operating voltage. When a low-value resistor or conductive path is connected across the test point connectors A and B, the circuit measures the resulting voltage drop or current flow, allowing the Arduino Uno to calculate the resistance using Ohm's law. A push-to-on switch (S1) serves as a user interface control, likely used to initiate a measurement or reset the baseline reading. Once calculated, the measured resistance value is sent to a 16x2 LCD display (LCD1), providing an immediate, real-time visual readout of the low-ohm measurement. The entire system is assembled compactly on a single-side PCB, integrating the power regulation, processing, user control, and display components into a cohesive test and measurement instrument programmed via the Arduino IDE using the mR_Meter.ino sketch.

Why Build This

Accurately measure low-value shunt resistors used in high-current power supply and motor control circuits.

Evaluate printed circuit board trace resistances and contact resistances in high-reliability engineering applications.

Develop a specialized, microcontroller-based test and measurement instrument for an undergraduate electronics workbench.

Real-World Application

Useful for electronics hobbyists, engineers, and technicians who need to measure low-value shunt resistors, trace resistances, and contact resistances in various electronic circuits and power supplies.

Skills You'll Learn

Low-resistance measurement techniques

analog-to-digital conversion

power regulation circuit design

microcontroller firmware integration

LCD interface implementation

Safety Precautions

Ensure power is disconnected before modifying wiring or soldering components on the PCB.

Technology Tags

ARDUINO

ADC

OHM'S LAW

CONSTANT-CURRENT SOURCE

MICROCONTROLLER

LCD DISPLAY

PCB DESIGN

Frequently Asked Questions

Why is a specialized milli-ohm meter necessary instead of a standard digital multimeter?

Standard multimeters often struggle to accurately resolve resistances below 1 ohm due to the inherent resistance of their own test leads and internal circuitry. This dedicated meter is specifically designed to measure the 0.1 to 1-ohm range with higher precision.

How do I load the software onto the Arduino Uno?

You will need to open the mR_Meter.ino sketch using the Arduino IDE on a computer, connect your Arduino Uno via USB, and upload the code directly to the board.

What is the purpose of the MIC5219 low-dropout regulator in this circuit?

The MIC5219 IC1 ensures that the system receives a stable and steady DC voltage from the 9V power source, protecting sensitive components and preventing voltage fluctuations from interfering with precision analog measurements.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

PRJ-00646