Project Hub /Test & Measurement Instrumentation/Multimeters, Voltmeters & Ammeters/Smallest Portable Ammeter and Energy Monitor Device

Intermediate

INDUSBOARD

Project Specific

3 – 6 Hours

Partial Kit

Smallest Portable Ammeter and Energy Monitor Device

A coin-sized portable ammeter and energy monitor built using the IndusBoard Coin, capable of measuring AC/DC current, calculating energy usage, and determining AC frequency.

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.

10pcs - 220 ohm 1/4 W Resistor Set Rs. 39.00
0.96 Inch I2C/IIC 4pin OLED Display Module White Rs. 349.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

This list includes a generic resistor set as a placeholder — it is not matched to the exact value or part number this circuit needs. The correct one is specified on the original source page linked above; check it before buying.

We don't carry yet: Battery (generic / unspecified)
Other Dev Board (Indusboard / Maixduino / misc)
Current Sensor ACS712

Browse all components

How It Works

The Smallest Portable Ammeter and Energy Monitor Device is engineered around the compact IndusBoard Coin microcontroller platform (U1), which acts as the central processing unit for data acquisition and calculation. To measure electrical current safely and effectively, the circuit integrates an ACS712 current sensor (S1). The ACS712 relies on the Hall effect principle, outputting an analog voltage proportional to the AC or DC current passing through its internal conduction path. Because the microcontroller's analog-to-digital converter requires precise voltage levels within safe operating bounds, a dedicated voltage divider network consisting of two resistors, R1 (12K) and R2 (6.6K), scales down the signals appropriately. Once the IndusBoard Coin processes these digitized voltage values, it computes key electrical parameters, including real-time current, calculated energy usage, and AC frequency. Finally, the processed data is rendered visually onto a compact SSD1306 OLED display (D1) connected via I2C or SPI, providing a crisp, real-time readout. The entire portable setup is powered by an independent battery and can be conveniently tapped into circuits using an alligator connector.

Why Build This

Perform on-the-go field measurements of AC/DC current and AC line frequency without being tethered to a benchtop multimeter.

Monitor power and energy consumption profiles of DIY electronics prototypes to optimize battery life and thermal performance.

Gain practical undergraduate-level engineering experience integrating Hall-effect current sensors with microcontroller data acquisition systems.

Real-World Application

Portable electrical testing, energy usage monitoring for DIY electronics, field measurement of AC/DC current and frequency.

Skills You'll Learn

Hall-effect current sensing

analog signal conditioning

voltage divider design

display interfacing via SSD1306

embedded power calculations

AC frequency measurement

Safety Precautions

Exercise caution when measuring live AC voltages and currents to avoid electrical shock.

Frequently Asked Questions

Can this device measure both AC and DC current?

Yes, the integrated ACS712 sensor is capable of measuring both alternating current (AC) and direct current (DC) signals.

What is the purpose of the 12K and 6.6K resistors?

Resistors R1 and R2 form a voltage divider network to scale down and condition the input signals so they are safe and compatible with the IndusBoard Coin's analog pins.

How is the device powered in portable mode?

The system is powered by an onboard battery, making it entirely self-contained for portable field 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-01123