RS-485 Shield for WeMos D1

RS-485 Shield for WeMos D1 is a half-duplex RS-485 to TTL Serial transceiver board for WeMos D1 ESP8266 microcontrollers. This board was designed mainly for easy Wifi to Modbus connectivity using HomeAssistant‘s ESPHome Modbus Component.


  • RS-485 chip: MaxLinear SP3485 or any other pin compatible RS-485 to TTL serial transceiver
  • RS-485 connector: RJ45 or 3.5mm 3-pin screw terminal
  • Supply voltage: 3.3V from WeMos D1 board
  • Logic level: 3.3V
  • Serial interface connects directly to UART interface on the WeMos D1 (Serial debug should be disabled)



  • Prototype boards in production

1-Wire Shield for WeMos D1

1-Wire Shield for WeMos D1 is 1-Wire to i2c bus converter board based on Maxim DS2482-100 Single-Channel 1-Wire Bus Master chip. It is used to off-load the time critical 1-Wire waveform generation from the MCU to the 1-Wire Bus Master to achieve error free operation with longer 1-Wire bus situations. Board header layout is compatible with WeMos D1 mini microcontroller boards. There is on-board strong pull-up mosfet and the level converter for 5V to 3.3V i2c interface.


  • 1-Wire device: Maxim DS2482-100 Single-Channel 1-Wire Master
  • 1-Wire connector: RJ45 (RJ12 or 3-pin 3.5mm screw terminal on request)
  • Supply voltage: 5V from WeMos D1 board
  • i2c logic level: 3.3V
  • 1-Wire logic level: 5V
  • Strong pull-up capability




  • Bare PCB: 3€