VAMeter Edu: Easy Tester for Everyone Learning Electricity

Why I made this project

I am a public middle‑school science and technology teacher in Japan.
Electricity is invisible to the eye. For beginners, that makes it abstract and difficult to grasp.
For many students, their first lessons on electricity become a major hurdle in their science education. Complicated wiring, abstract numbers, and the fear of making mistakes can lead them to think, “Physics is not for me.”

My stance: let’s flip that script for beginners.
Electricity is a friend for Makers, not a fear.

What is VAMeter Edu?

VAMeter Edu is a modified version of the open‑source data logger M5Stack VAMeter.
It retains the key strengths of the original—such as the waveform display and M5 EZData Cloud Platform—while introducing several modifications designed for beginners.

• Custom case with jacks that works with a commercial test lead (“Normal Probe”).
• Simplified tester UI (beginner‑friendly order; still under development for the Normal Probe).
• Training Probe + Training UI with an answer‑check function for practicing analog meter reading.

Note: the Normal Probe is off‑the‑shelf (Test Lead TL‑38) and not developed in this project. What I developed here is the jack‑equipped case, the Training Probe, and the training‑oriented firmware/UI.

Hardware Overview

The VAMeter Edu is built around the M5Stack VAMeter core, housed in a custom-designed, 3D-printed enclosure. The case is specifically designed for classroom use, featuring robust banana jacks for commercial test leads and dedicated RCA jacks for the custom Training Probe.

• Photo 1 – Complete VAMeter Edu system:
  The complete VAMeter Edu system. Pictured are the main unit, the Training Probe with Combined Terminals (left) for guided practice, and the commercial test lead "Normal Probe" (right) for general measurements.
• Photo 2 – Jack layout (top view):
  The top panel features a clear, simple layout. The standard 4mm banana jacks (+ Common, – Current, – Voltage) are used with commercial test leads. The two RCA jacks at the back connect the Training Probe, allowing simultaneous use with an analog meter.
• Photo 3 – Completed device:
  A closer view of the 3D-printed enclosure, highlighting the side-mounted RCA jacks for the Training Probe. This design keeps wiring clean, safe, and accessible for students.

Two probes, two roles

Normal Probe (commercial test lead)

For everyday voltage/current measurement with VAMeter Edu. It shows the numeric value and the waveform, helping beginners literally see electricity.

• Current measurement with VAMeter Edu — Circuit using the Normal Probe to measure current. VAMeter Edu is connected in series across the lamp and battery, so students can observe the current value and waveform on the display.
• Voltage measurement with VAMeter Edu — Circuit using the Normal Probe to measure voltage. VAMeter Edu is connected in parallel across the lamp, showing both voltage value and waveform.

Training Probe (for analog‑meter practice)

Beginners still need to learn how to read an analog meter. The Training Probe allows students to first read the needle on the scale, and then check the correct digital value—all without having to rewire their circuit.

Combined Terminal — a small adapter that stacks onto each analog‑meter terminal:

• Banana plug → stack on the analog meter
• Banana jack → continue the circuit
• RCA jack → two‑core cable to VAMeter Edu

This keeps wiring tidy while the analog meter and VAMeter see the same current (series) or same voltage (parallel).

• Training for Current measurement:
  Measurement circuit using the Training Probe with Combined Terminals. VAMeter Edu is in series with the analog ammeter, so students read the needle and then verify the value digitally.
• Training for Voltage measurement:
  Measurement circuit using the Training Probe with Combined Terminals. VAMeter Edu is in parallel with the analog voltmeter, so—just as with current measurement—students read the needle and then verify the value digitally.

How the UI supports learning

• Self-Check Feature (Training Probe only): The digital value is hidden by default. Students press the dial to reveal the correct answer after they've taken their own reading from the analog meter.
• Other supports: a startup connection hint screen (what the dial does / where to connect), simple mode selection (Voltage or Current), and schematic‑style guidance to reinforce parallel vs. series.

The flowchart below illustrates the simple but powerful learning loop designed for the Training Probe.
The process begins with a clear connection guide—series for the ammeter, parallel for the voltmeter—to reinforce correct wiring. From there, learning occurs in a simple three-step cycle:

• Read: The student reads the analog meter while the digital value remains hidden.
• Check: A press of the dial reveals the correct digital value for an instant self-check.
• Repeat: Releasing the dial hides the value, encouraging the student to read the analog scale again to solidify their understanding.

This “Read, Check, Repeat” cycle is fundamental to building both skill and confidence at the student's own pace.

Classroom practice (Training Probe + training firmware)

• Location: a public middle school in Hyogo, Japan
• Participants: 156 grade‑8 students (4 classes)
• Period: Oct 28 – Dec 6, 2024 (three lessons: wiring & ammeter‑connection practice / current measurement / voltage measurement)

Students using VAMeter Edu with the Training Probe during a middle-school science lesson. They read the analog meter first, then press the dial switch to reveal the digital value for self-checking.
All 28 groups finished within class time, and the self-check feature proved very effective. Many students used it to notice and correct their own reading mistakes on the spot.

• Student feedback: over 85% rated the training tool as helpful.
• Reading accuracy for analog meter:
• Baseline from a national survey (Japan, 2012) for ammeter reading: 45.4% correct.
• After lessons with the training tool: 68.3% correct (ammeter), 64.0% correct (voltmeter).

Future work (open to collaborators)

Add protection features for safe classroom use:

• Glass fuse on the VAMeter +IN terminal to prevent damage from wiring mistakes.
• Current-limit cutoff (relay OFF if limit exceeded) to protect both the device and external circuits.
• Automatic calibration to match the analog needle and digital value precisely.
• Data link to student devices (CSV/Sheets) and accessibility features (voice read‑out), and multi-language UI.
• A context-sensitive "Help" button for on-demand guidance.
• Finalize the beginner‑friendly tester UI for the Normal Probe.

Firmware status (Aug 22, 2025): the Training Probe firmware is complete and was used in classroom practice. The Normal‑Probe UI redesign is still under development.

Why this speaks to educators and makers

For educators, VAMeter Edu makes circuit experiments easier and safer. Students can practice reading analog meters and immediately check their answers, building both skills and confidence.
For makers, it shows how small design changes—like probes, UI tweaks, and protection features—can turn an open-source tool into a practical teaching device.

References (for further reading)

• Harada, Sakamoto, Suzuki (2018). When and Why Have Lower Secondary School Students Disliked Science Learning?
  https://doi.org/10.11639/sjst.17028
• Miyata & Muroya (2009). Survey of Improvement of Operational Skill Teaching on Experimental Tools in Lower Secondary School.
  https://doi.org/10.11639/sjst.KJ00006252539
• National Institute for Educational Policy Research (2012). National Assessment of Academic Ability – Science, Junior High School.
  https://www.nier.go.jp/12chousakekkahoukoku/04chuu-gaiyou/24_chuu_houkokusyo-4_rika.pdf