This small adapter allows OpenEnergyMonitor products to be used with a WiFi connection. The module is fully supported by ESPHome and is compatible with many end points, for example emonCMS, Home Assistant, and MQTT.
It is available for the following OpenEnergyMonitor products:
The adapter uses an Espressif ESP32-C3 and connects to the emonTx's serial port.
Warning
You must not connect the USB-C port of the emonWiFi while the emonWiFi is plugged into an emonTx. Doing so can cause damage to your emonTx.
To install firmware for the first time, hold down the push button on the emonWiFi while plugging in the USB-C cable. This puts the ESP32 module into bootloader mode which allows firmware to be uploaded over the USB connection. After the first upload, you can use OTA updates.
The emonWiFi is natively supported by ESPHome. You can find instructions here or setup directly from Home Assistant.
The ESPHome configuration snippet for the emonWiFi is:
uart:
id: emontx_uart # using UART2
rx_pin: GPIO20
tx_pin: GPIO21
baud_rate: 115200
rx_buffer_size: 2048You need to fit the connectors that correspond to the device you are attaching it to. There are different headers for each of the boards listed above. The headers face downwards, away from the side with the USB-C socket.
For an emonPi3 and emonTx6, a 2x5 pin header is installed in the position marked Pi3.
For an emonPi2 and emonTx5, a 5 position socket is installed in the position marked Pi2.
For an emonTx4, a 6 position socket is installed in the position marked Tx4.
Warning
You must remove power from the emonTx before installing the emonWiFi. Failure to do so can result in damage to either, or both, of the devices.
Warning
Ensure you have placed the emonWiFi into the correct position for your emonTx before applying power. Failure to do can result in damage to either, or both, of the devices.
Note
If you want to configure the emonTx4 over the WiFi connection, you must remove the solder bridge marked JP6. With this removed, you will not be able to configure the emonTx4 using the USB-C port.
With the emonTx4's USB-C port facing downwards, insert the emonWiFi into the 6 pins in the centre left. The emonWiFi's USB-C port should face to the right.
Note
If you want to configure the emonTx5 over the WiFi connection, you must cut the pad marked USB_TX. With this cut, you will not be able to configure the emonTx5 using the USB-C port. You can restore this functionality by applying a small solder bridge over the USB_TX pads.
With the emonTx6's USB-C port to the right, insert the emonWiFi into the pins below the Raspberry Pi socket as far to the right as possible with the emonWiFi's USB-C port also to the right.
With the emonTx6's USB-C port to the right, insert the emonWiFi into the 40pin socket towards the bottom as far to the right as possible with the emonWiFi's USB-C port also to the right.