Gardena Bluetooth Bridge

Bring a Gardena Smart Dual Water Control (G-19034) into Home Assistant over MQTT — no gateway, no ESPHome.

Before you flash: you need an existing MQTT broker (e.g. mosquitto) that Home Assistant is already talking to. This page only installs the bridge firmware — WiFi and MQTT are configured after flashing, from the device's own setup page.

1. Pick your board and flash

Use Chrome or Edge (Web Serial support is required), plug the board in over USB, then click Install below and select the serial port when prompted.

ESP32-S3Verified

The board this project was built and is deployed on.

Web Serial isn't supported in this browser — use Chrome or Edge. This page must be served over HTTPS to flash.

ESP32 (original)Untested

Cheapest/most common variant. Needs a USB-UART dev board (no native USB).

Web Serial isn't supported in this browser — use Chrome or Edge. This page must be served over HTTPS to flash.

ESP32-C3Untested

Cheap, low-power, native USB.

Web Serial isn't supported in this browser — use Chrome or Edge. This page must be served over HTTPS to flash.

ESP32-C6Untested

Newest low-power variant.

Web Serial isn't supported in this browser — use Chrome or Edge. This page must be served over HTTPS to flash.

Untested boards should work — the bridge's BLE code uses MicroPython-level IRQ numbers, not chip-specific ones — but only the S3 has been confirmed against a real Gardena valve. If you try one of the others, please open an issue and report back either way.

2. First-boot setup

  1. After flashing, the device reboots into an open WiFi access point named GardenaBridge-XXXX. Join it from your phone or laptop.
  2. Open http://192.168.4.1 in a browser.
  3. Fill in your WiFi SSID/password, MQTT broker IP + credentials, and the Gardena's BLE address — use the page's Scan for Gardena button to find it instead of typing it, if the valve is nearby and powered.
  4. Save. The device reboots onto your WiFi and starts publishing to MQTT / appearing in Home Assistant.
Before first connect: factory-reset the Gardena valve (hold the manual-control button while inserting the battery, ~10s, until 3 LEDs flash) — its single BLE bond slot must be empty. Also force-close the Gardena phone app and turn the phone's Bluetooth off, or it will grab the bond first. The bridge bonds automatically on its first poll — no button presses needed on the bridge side — but only if the valve's bond slot is free when it does.

3. Reconfigure or update later

Once on WiFi, the same setup page is served at the device's own IP (shown in Home Assistant as an _ip sensor). It also serves /ota for pushing firmware updates over WiFi, no USB required.