Project Hub /Test & Measurement Instrumentation/Multimeters, Voltmeters & Ammeters/Simple Millivolt Meter Using Arduino

Intermediate

ARDUINO

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

Simple Millivolt Meter Using Arduino

Build a simple millivolt meter circuit using an Arduino Uno and a 16x2 LCD display to measure low voltages starting from one millivolt onwards.

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
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)
Magnets / Electrodes / Probes
9V Battery + Snap

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How It Works

The Simple Millivolt Meter project turns an Arduino Uno into a dedicated low-voltage measurement tool by using the microcontroller's internal Analog-to-Digital Converter (ADC). When you touch the test probes to a circuit, the input voltage is routed into one of the Arduino's analog input pins. The Arduino reads this continuous analog signal and converts it into a digital value through its built-in ADC. Because standard analog reads output a raw value based on a 5-volt reference, the software inside the 'mV_Meter.ino' source code applies mathematical scaling to convert that raw digital data specifically into millivolts. Once the microcontroller calculates the correct millivolt value, it formats the data and sends it out to a connected 16x2 LCD display. The display screen refreshes continuously, allowing you to view real-time fluctuations in the low-level voltage being tested. Power for the entire system is supplied independently via a 9V battery or a 9V 500mA adapter, which feeds the Arduino's onboard voltage regulator to keep the logic stable while taking measurements.

Why Build This

Gain hands-on experience designing specialized test instruments for physics and electronics labs that demand precise low-voltage tracking.

Learn how to repurpose everyday microcontroller development boards into custom measurement tools instead of relying solely on commercial multimeters.

Develop practical skills in integrating character displays with microcontrollers to output real-time sensor data clearly.

Real-World Application

Useful for hobbyist and DIY electronics projects requiring precise measurement of low-level voltages where standard multimeters lack sufficient resolution.

Skills You'll Learn

Analog-to-digital conversion

LCD display interfacing

basic voltage scaling and math in software

circuit probing techniques

microcontroller power management

Safety Precautions

Do not attempt to measure voltages above 1V, negative voltages, or reverse the polarity of the test cables, as doing so may destroy the Arduino board.

Technology Tags

ARDUINO

ADC

LCD DISPLAY

TEST PROBES

MEASUREMENT

MICROCONTROLLERS

Frequently Asked Questions

Can I use this meter to measure standard household electrical outlets?

No. This circuit is strictly designed for very low voltages starting from one millivolt onwards and cannot measure voltages above 1V without damaging the board.

Do I need a breadboard or can I solder the components permanently?

You can use either a breadboard for temporary prototyping or a custom PCB if you want a more permanent, rugged testing tool.

What software do I need to program the Arduino Uno?

You will need the Arduino IDE installed on your computer to open and upload the 'mV_Meter.ino' source code file to your board.

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.

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