Sonoff THR320D Elite Smart Temperature Humidity Monitoring Switch

The THR320D Elite features an RJ11 port for connecting compatible probes like the THS01 or DS18B20. For the DS18B20, you may need an adapter (like the one included with MS01). Simply plug the sensor's RJ11 connector into the port on the switch—it supports hot-plugging. The device will automatically detect the sensor and begin displaying its readings on the LCD and within the eWeLink app, allowing you to set automation rules based on its data.

Yes, the switch supports LAN control mode. Once configured via the eWeLink app, it can communicate directly with your phone on the same local network without needing an active internet connection. Scheduled automations and sensor-based triggers programmed into the device will continue to function. However, remote access from outside your network and push notifications will require the internet to be restored.

For custom firmware, you typically need to access the ESP32's serial pins, which may require opening the case. Using tools like ESPHome or Tasmota, you can flash firmware via a USB-to-serial adapter. For Home Assistant integration without reflashing, use the official eWeLink add-on or the Sonoff LAN integration in HACS. This allows local control and automation. Ensure your Home Assistant instance and the THR320D are on the same subnet for discovery.