GbbDongle

GbbOptimizer ↔ Modbus RTU proxy for off-the-shelf ESP32 RS485 boards

Pick your board, connect it over USB and click Install to flash the latest firmware straight from your browser (Chrome or Edge required).

Each board comes in two firmware flavours:

Factory Image (default) — the standalone GbbDongle product. No Home Assistant integration; the web dashboard and firmware uploads are protected by a password (default admin / admin, changeable on the device's web page).
Home Assistant-compatible — exposes the ESPHome native API and offers itself for adoption in the ESPHome dashboard. After adoption you build and maintain your own configuration (bring your own support).

Waveshare ESP32-S3-RS485-CAN

ESP32-S3 · WiFi · BLE provisioning · isolated RS485

Waveshare ESP32-S3-POE-ETH-8DI-8DO (WiFi)

ESP32-S3 · WiFi · BLE provisioning · isolated RS485 (auto-direction)

WiFi needs the external SMA antenna attached (no onboard antenna). For wired networking flash the Ethernet variant instead.

Waveshare ESP32-S3-POE-ETH-8DI-8DO (Ethernet)

ESP32-S3 · Ethernet + PoE (no WiFi) · isolated RS485 (auto-direction)

Same board as the WiFi card — this firmware is Ethernet-only (WiFi/AP/BLE not compiled in).

LilyGo T-CAN485

ESP32 · WiFi · auto-direction RS485

Kamami KAmod ESP32 ETH+PoE

ESP32 · Ethernet + PoE (no WiFi) · KAmodRPi UART RS485 ISO HAT (isolated, auto-direction)

Flash over USB with the RS485 HAT removed — the USB converter and the HAT share the same UART pins.

After flashing

WiFi boards (Waveshare boards — WiFi variant, LilyGo):

Join the GbbDongle Setup WiFi access point and configure your WiFi.
Open the device's web page (its IP address, shown in the captive portal).

Kamami (Ethernet-only): unplug USB, mount the RS485 HAT, plug in Ethernet (PoE or 5 V) — the device gets an address via DHCP; open http://gbbdongle-kamami.local or its IP address from your router.

Waveshare 8DI-8DO (Ethernet variant): plug in Ethernet (PoE or USB/7–36 V power) — the device gets an address via DHCP; open http://gbbdongle-8di8do-eth.local or its IP address from your router.

Then, on the device's web page:

Factory Image only: log in with admin / admin and set your own password in the Admin Password field (it also protects firmware uploads).
Fill in MQTT Server, Plant Id and Plant Token from your GbbOptimizer account.
Press Apply Settings (Restart).
Wire RS485 A/B to your inverter's Modbus port.

Home Assistant-compatible image: the device shows up as Discovered in the ESPHome dashboard next to your Home Assistant — click Adopt (or add it to Home Assistant directly; the API encryption key is generated on first connection). After adoption the configuration is compiled by your own ESPHome dashboard.