Real-time dashboard for the ZOYI ZT703s multimeter, running entirely in the browser. Connect the meter over the Web Serial API, watch live readings on a large digital display and a rolling trend chart, capture a logging session with running statistics, and export the result to CSV — no backend, no installation.
https://fyfar.github.io/multimeter-live/
Open it in a supported browser (Chrome, Edge, Opera, or Firefox 151+), connect your meter, and click Connect. Everything runs locally in your browser — no data leaves your machine.
Multimeter·Live is a Progressive Web App (PWA), so there is nothing to
download and no platform-specific build — no .exe, no .dmg, no app store.
The web app is the app. In a supporting browser you can install it (the
address-bar install icon) to launch it in its own window, with its own icon, just
like a native desktop program.
After your first visit it also works fully offline — handy on a bench or in the field with no Wi-Fi, since the meter connects over USB and nothing in the app needs the network. The same install runs on Windows, macOS, Linux, and ChromeOS; the browser handles the packaging, so there are no separate binaries to maintain or trust.
When a new version is published, the app doesn't reload on its own (that would interrupt a recording). Instead it shows a small "A new version is available — Reload / Later" message, so you update on your terms. You never reinstall to update.
Not an official ZOYI / ZOTEK product. Multimeter·Live is an independent, community-built project and is not affiliated with, endorsed by, or supported by ZOYI or ZOTEK. "ZOYI", "ZOTEK", and "ZT703s" are referenced only to describe the hardware this tool works with.
Device support: Built specifically for the ZOYI ZT703s and its serial packet format. The ZT703s+ and ZT706 likely use the same protocol and may work, but they are untested. Other multimeters are not supported.
- Live digital readout of the current measurement, mode, unit, and resolution
- Rolling trend chart with selectable time windows — 10 s, 1 m, 10 m, 1 h, or all (plots the entire session)
- Session logging with running statistics: average, min, max, peak-to-peak, sample count, and standard deviation
- Trigger auto-logging — arm a threshold and recording starts automatically when the measured magnitude crosses it, then stops once it falls back below (hysteresis, so a signal hovering at the edge doesn't flap logging on and off)
- Auto-scale or manual Y-axis range, with out-of-range samples flagged on the chart
- CSV export of the recorded session (timestamp, mode, value, unit)
- Configurable baud rate (9600–115200)
- Supported modes: voltage, current, resistance, continuity, diode, capacitance. Values are normalized to canonical base units (e.g. mV → V) so a mid-stream unit switch doesn't make the chart jump.
- A ZOYI ZT703s multimeter connected over USB serial (see device note above).
- A browser with the Web Serial API: any Chromium-based browser (Chrome,
Edge, Opera) or Firefox 151+ on desktop (added May 2026).
Safari is not supported. On Firefox Enterprise builds, Web Serial is disabled by default
and must be enabled via the
DefaultSerialGuardSettingpolicy. - A served origin of
https://orlocalhost— Web Serial requires a secure context. The live demo is served over HTTPS, so it works out of the box.
npm install
npm run devOpen http://localhost:3000, click Connect, and pick your serial port from the browser prompt.
Issues and pull requests are welcome! If you have a ZT703s+ or ZT706 and can confirm whether it works, or you'd like to add a feature or fix a bug, please open an issue or send a PR.