RS-485 Shield for WeMos D1 Mini

March 21, 2023 |   |  Comment  |  ModBus, Wifi

RS-485 Shield for WeMos D1 is a half-duplex RS-485 to TTL Serial transceiver board for WeMos D1 Mini (ESP8266) and WeMos C3 Mini (ESP32) microcontrollers. This board was designed mainly for easy Wifi to Modbus connectivity using HomeAssistant‘s ESPHome Modbus Component.

Features

  • 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
  • Logic level: 3.3V
  • Serial interface connects directly to UART interface on the microcontroller (Serial debug should be disabled)
  • Esphome pins on WeMos D1 Mini (ESP8266) boards:
    • TX: 1
    • RX: 3
    • Flow control: 2
  • Esphome pins on WeMos C3 Mini (ESP32) boards:
    • TX: 21
    • RX: 20
    • Flow control: 6

Resources

Buy

  • Bare PCB: 3€
  • Pre-assembled: 12€

1-Wire Shield for WeMos D1

April 22, 2018 |   |  Comment  |  1-Wire, Wifi

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.

Features

  • 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

Resources

Credits

Buy

  • Bare PCB: 3€ 
  • Pre-assembled: 17€