gPlug HA

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Home Assistant MQTT Auto-Discovery for the gPlug smart meter interface, as a Tasmota Berry app — no manual YAML configuration on the Home Assistant side.

Tasmota's own, earlier HA discovery feature (SetOption19) was removed at the firmware level. This app fills that gap, specifically for the gPlug's built-in smart meter (P1-DSMR, Kamstrup HAN, or M-Bus, depending on model), not as a generic Tasmota-sensor-to-HA bridge.

No YAML, no Home Assistant add-on, no custom integration to install. All the logic lives on the gPlug itself; Home Assistant only needs its built-in MQTT integration, already talking to your broker.

What it does

• Reads the gPlug's built-in smart meter locally via Tasmota's SML sensor (tasmota.read_sensors()), resolving the actual variable names from script.txt by their OBIS code — works across meters that use different variable names for the same measurement.
• Publishes every value the meter reports: aggregate and per-phase active power (import/export), voltage and current per phase, reactive power, power factor, energy import/export (including per-tariff registers for two-tariff meters, when the meter actually reports them), and reactive energy.
• Publishes gPlug/Tasmota device diagnostics too: ESP32 temperature, free heap, uptime, last restart reason.
• Publishes a Home Assistant MQTT device discovery message so all of the above shows up as entities automatically, with no YAML.
• Updates on every smart meter reading (not a fixed polling interval), re-publishes discovery if the meter's ID changes (e.g. after a meter replacement), and re-publishes discovery when Home Assistant (or the broker) restarts.
• Guards cumulative energy counters against momentary zero readings (a transport/parsing glitch), so a bad reading can't be mistaken for a meter reset and corrupt Home Assistant's long-term energy statistics.
• A small status badge on the Tasmota web UI shows the app is running, linking back to this repo.

What you get in Home Assistant

One device, with sensors grouped by kind — reading values, per-phase power/energy detail, and device diagnostics all show up automatically:

This relies entirely on Home Assistant's built-in MQTT integration, via its MQTT discovery mechanism. Once the app is running on the gPlug and publishes its first discovery message, the device shows up on its own under Settings → Devices & Services → MQTT — no manual entity setup, no extra integration to install.

Installation

1. Download the latest gplug_ha.tapp from Releases (or build it yourself, see below).
2. On the gPlug's Tasmota web UI: Tools → Manage filesystem → Upload, select gplug_ha.tapp.
3. Restart the device (Restart button on the main page). No further configuration needed — Tasmota scans for *.tapp files at boot and runs them automatically.
4. In Home Assistant, check Settings → Devices & Services → MQTT: the smart meter device (named "Smart Meter <SMid>") appears there automatically, with all its entities.

Your gPlug's MQTT broker must already be configured in Tasmota (Configuration → MQTT) and set up as an integration in Home Assistant; this app uses that existing connection and doesn't manage its own credentials.

Building from source

cd berry
./build_tapp.sh

This precompiles gplug_ha.be and gplug_ha_setup.be to Berry bytecode and packs both into gplug_ha.tapp. The first run builds and caches a matching berry CLI compiler (from the exact Tasmota firmware source tag, since Tasmota patches Berry); subsequent runs reuse the cached binary. Requires curl, make, and Python 3.

For firmware without automatic .tapp scanning, autoexec.be.example shows the single-file installation path instead (upload gplug_ha.be, gplug_ha_setup.be, and autoexec.be separately).

MQTT topics

All topics use the smart meter's own ID (SMid), not the device's Tasmota topic, so they stay stable across device reconfiguration:

Topic	Content	Update cadence
gplug-ha/<smid>/state	Grid power, voltage/current per phase, power factor, meter status	every meter update
gplug-ha/<smid>/power	Per-phase power import/export/net, reactive power	~every other minute
gplug-ha/<smid>/energy	Energy import/export (+ tariffs if present), reactive energy	~every other minute
gplug-ha/<smid>/diag	ESP32 temperature, free heap, uptime, restart reason	~every other minute
homeassistant/device/<smid>*/config	HA MQTT discovery (four messages, one device)	on first detection, meter change, or HA restart

Optional: reducing publish frequency

If you only use the Home Assistant Energy dashboard and don't need second-precise live readings, you can slow this app down to cut recorder/state_changed volume. Create a gplug_ha.cfg file (JSON) next to script.txt on the gPlug's filesystem (Tools → Manage filesystem → Create new file) and restart:

{"state_interval_s": 30, "power_interval_s": 60, "diag_interval_s": 300, "energy_interval_s": 300}

• state_interval_s (default 0): minimum seconds between state topic publishes (grid power, voltage/current per phase, power factor). 0 means "every smart meter update", the default - useful to keep fast if something (e.g. a PV controller) relies on live grid power.
• power_interval_s, diag_interval_s, energy_interval_s (each default 120): minimum seconds between publishes of the power, diag, and energy topics respectively - fully independent of each other, so e.g. energy (cumulative meter readings, all the Energy dashboard actually needs) can be slowed down without affecting power or diag.
• detail_interval_s (default 120, legacy): sets the shared default for power_interval_s, diag_interval_s, and energy_interval_s when one of those isn't set explicitly. Still supported for configs written before the three above existed.

A missing or invalid file keeps the defaults - this is a local file, not a remote setting, so a restart is needed for changes to take effect, same as editing script.txt.

Known limitation

Tasmota occasionally logs BRY: ERROR, bad json for an outgoing MQTT publish from this app, on both real gPlug hardware tested during development. The cause hasn't been fully root-caused - it does not appear to correlate with payload size or with the number of mqtt.publish() calls in quick succession, and observed data delivered to Home Assistant was not found to be affected. If you notice actual missing/stale entity updates rather than just this log line, please open an issue with your script.txt and console log around the time of the gap.

Requirements

• gPlug (gPlugD/-D-E/-K/-M) with Tasmota, USE_BERRY and the smart meter module (USE_SCRIPT, SML sensor) compiled in.
• ESP32-C3 without PSRAM — this app is written with that memory budget in mind.

Credits

• The Home Assistant mark shown in the Tasmota web UI status badge is the official "Home Assistant" glyph from the Simple Icons project (CC0-licensed).
• Tasmota and its Berry scripting language.

License

MIT

This is an independent community project, not affiliated with or endorsed by the makers of the gPlug, Home Assistant / Nabu Casa, or the Tasmota project. All product names and marks belong to their respective owners.