SlimmeLezer + esp32 + ethernet

WT32-ETH01 based

For this version I was looking for an esp32 and ethernet. The best version I could find is the WT32-ETH01 from wireless-tag. These boards can be found on AliExpress for around €15 (including shipping)

I've designed this prototype for using ethernet only. Obviously the wireless network can be used too. The down side of esp32 + wifi + esphome is that it draws quite a lot of power (and with a lot I mean >250mA). Therefore it must be powered via the USB-C port to provice the necessary power.

On my test meter Sagemcom T210-D (DSMR 5) and my personal meter ISKRA AM550 (DSMR 5) the P1 port provides enough power for using it with ethernet.

Pin-out

Serial pins for flashing the esp32

Looking at the top-part of the pin-out image, those pins are used for flashing the esp32. The TXD0, RXD0, IO0, EN, GND and 3v3. Those pins are directly connected to the ch340 serial chip.

Serial pin for data

In the middle left you see the RXD and TXD for serial communication. Only the RXD is used as DSMR is an oneway communication protocol.

uart:
  id: uart_dsmr
  baud_rate: 115200
  rx_pin: GPIO5
  rx_buffer_size: 1700

And for the DSMR the id: uart_dsmr is used:

dsmr:
  uart_id: uart_dsmr
  id: dsmr_instance
  max_telegram_length: 1700

Ethernet pins for ESPHome

The following settings are used in case of using ESPHome:

ethernet:
  type: LAN8720
  mdc_pin: GPIO23
  mdio_pin: GPIO18
  clk_mode: GPIO0_IN
  phy_addr: 1
  power_pin: GPIO16

See more information about ethernet and esphome on their website.

The device

Assembled