We previously wrote about Ebyte E180-ZG120B-TB an inexpensive ($9.90) Zigbee 3.0 evaluation board based on Silabs EFR32MG1B Arm Cortex-M4 wireless MCU and the equally cheap ($7.78) WT32-ETH01 ESP32 Ethernet board. What do they have in common? Absolutely nothing!
But GitHub user tube0013 decided to connect both boards over UART to create a Zigbee to Ethernet DIY coordinator/bridge running open-source firmware.
The hardware also includes a Micro USB adapter for power, several 10cm jumper wires, and he/she also designed a 3D printed case.
EZSP-Firmware is used for the Ebyte Zigbee 3.0 board, and ESPHome open-source home automation firmware for the ESP32 board. You’ll also need serial to IP code and ESPHome config. Note that flashing firmware to the Ebyte requires a programmer, and the developer used a J-link EDU Mini together with Silicon Labs’ Simplicity Commander.
As mentioned above, a 3D printed case has also been designed, so everything is neatly packed together. The total cost assembled should be around $20.
The Zigbee to Ethernet bridge can then be added Home Assistant using socket://IP:6638. You can also change the port in the serial to IP source code.
This type of solution can be more stable and reliable than WiFi to Zigbee bridges as both wireless protocols operate in the same 2.4GHz frequency and may interfere with each other. We’ve also been told most serial protocol; connections are not resilient enough to handle serial packet loss or loss of sync. The project could easily be adapted to other serial wireless modules as well.
The discussion also mentioned SM-011, a tiny EFR32MG21 Zigbee 3.0 module that could be integrated into a smaller gateway, or make the base for a compact, single board based on ESP32 for Ethernet and EFR32MG21 for Zigbee.
Thanks to Andreas for the tip.