RS485 Bridge – ESP32‑C6 WiFi/Zigbee
RS485 to WiFi/Zigbee Bridge (ESP32‑C6)
A compact interface board that uses the ESP32‑C6 to bridge RS485 / Modbus RTU devices to WiFi or Zigbee.
Ideal for integrating heat pumps, ventilation units, energy meters, and industrial sensors into Home Assistant or other automation systems.
What this board does
This board allows you to:
- Connect RS485 / Modbus RTU devices to WiFi or Zigbee
- Use ESPHome, custom firmware, or ESP-IDF/Arduino code
- Integrate heat pumps, ventilation units, and energy meters into Home Assistant
- Replace bulky RS485 gateways with a compact ESP32‑C6 solution
If you need to bridge RS485 to WiFi, RS485 to Zigbee, or read/write Modbus RTU, this board provides a ready‑to‑use hardware platform.
Example devices you can communicate with
I personally use this board to connect my Nibe heat pump (F1255‑6 R PC) to Home Assistant.
Below is a list of community projects and devices that use RS485/Modbus and can potentially be interfaced with this board.
Please verify compatibility for your specific device.
- Nibe heat pump
- Mitsubishi Ecodan
- Alpha Innotec / Novelan
- Genvex
- Itho Daalderop ventilation units
- Danfoss ECL
- Systemair VTR series
- Eastron SDM72DM energy meters
- DDS238‑2 energy meters
- Carlo Gavazzi EM24 / EM340
- SolarEdge inverters
- Schneider PM2200
- Renke RS‑FXJT‑N01 wind direction sensor
Technical details
Main components
- ESP32‑C6
- COSMAX13487EESA (MAX13487E‑compatible) — Half‑duplex RS485/RS422 transceiver with automatic direction control
Internal connections
| ESP32‑C6 Pin | RS485 Transceiver Pin |
|---|---|
| GPIO4 | nSHDN |
| GPIO5 | nEN |
| GPIO6 | RO |
| GPIO7 | DI |
Connectors
The board includes:
- USB‑C (power + programming)
- 4‑pin spring terminal (RS485 + power)
Both connectors can be used simultaneously.
Spring terminal pinout
| Pin | Description |
|---|---|
| Vin | 12–24 V input (max ~40 mA @ 12 V) |
| GND | Ground |
| B | RS485 line B |
| A | RS485 line A |
FAQ
Can this board connect RS485 devices to WiFi?
Yes — the ESP32‑C6 bridges RS485/Modbus RTU to WiFi or Zigbee.
Does it support Modbus RTU?
Yes, it works with standard Modbus RTU over RS485.
Is it compatible with Home Assistant?
Yes — you can use ESPHome or custom firmware to integrate RS485 devices.
Can I power it from the RS485 device?
Only if the device provides a suitable 12–24 V supply.
Is it safe to connect to my heat pump or ventilation unit?
Yes, but incorrect wiring may cause damage. Double‑check polarity and wiring diagrams.
Links
-
NibeGW for ESP32‑C6
Integration gateway for Nibe heat pumps via ESP32‑C6 -
ESPHome for ESP32‑C6
ESPHome configuration and setup for the ESP32‑C6 - 3D‑printable housing
Notes
- Contact me if shipping rates for your country are not available.
- Incorrect wiring may damage your equipment. Use at your own risk.