RS-485+CAN bus+DCDC Converter Shield for WeMos Mini

June 7, 2023 |   |  Comment  |  CanBus, ModBus, Wifi

RS-485 + CAN bus + DCDC Converter Shield for WeMos Mini is a small three-in-one board to fit on top of WeMos Mini (ESP32) microcontroller boards:

  • RS485 to TTL Serial transceiver with automatic flow control connects UART compatible GPIO pins on the microcontroller.
  • CAN bus Transceiver is suitable for 12 V and 24 V systems and it connects to ESP32 integrated CAN controller via GPIO pins.
  • DC/DC Converter allows powering the board and the microcontroller with 3.3 V from ~12 V DC source.

This board offers an easy and compact way to connect NMEA-2000 bus and/or one NMEA-0183 (RS-485/RS-422) device to WiFi network on a small boat using NMEA2000-Gateway with ESP32 software getting power from the NMEA-2000 bus or separate ~12 V DC source like 12 V battery.

Features

  • 3.5mm screw terminals
  • Supply voltage: 12 VDC (3.8V-32V)
  • GPIO voltage: 3.3 V
  • DC/DC converter: AP63203
  • RS-485 transceiver with auto direction control: THVD1406
  • RS-485 interface connects to secondary UART on the WeMos Mini ESP32 boards
  • CAN bus transceiver: SN65HVD232
  • Optical isolation: none
  • GPIO pins for WeMos D1 Mini ESP32:
    •  RS-485
      • RX: GPIO16
      • TX: GPIO17
    • CAN bus
      • RX: GPIO19
      • TX: GPIO18

Resources

Buy

  • Bare PCB: 3€
  • Pre-assembled: 21€
  • Pre-assembled with terminals: 26€

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 socket (TE / MOLEX) or 3.5mm 3-pin screw terminal
  • Supply voltage: 3.3V (from WeMos Mini microcontroller board)
  • 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€
  • Pre-assembled with screw terminals: 17€
  • Pre-assembled with RJ45 socket: 17€

Atmega T245

February 14, 2023 |   |  Comment  |  Tools

Alternative open source controller for popular JBC T245 soldering iron using Atmega 328p micocontroller and P-Channel mosfet. The main goal for this project was to learn more about using different types of Mosfets for driving soldering iron heating elements. Atmega 328p can be programmed using Arduino IDE and this controller uses the same firmware source as Atmega Soldering Station by Stefan Wagner. It is not binary compatible because the original board uses N-Channel mosfet but this project uses P-Channel mosfet. There is a configuration option for selecting the correct mosfet version in the firmware source code.

Features

  • Based on Atmega 328p
  • Arduino code by wagiminator
  • P-Channel Mosfet
  • I2C OLED display support (two pinouts supported)
  • Buzzer
  • DC/DC step-down power supply
  • JBC T245 socket on the board
  • FTDI UART header for programming and debugging
  • 19-24V@5A DC power supply recommended
  • Header for connecting rotary encoder separately
  • 3,5mm terminal blocks for power and connecting soldering iron directly
  • Sides of the board can be cut off if not needed
  • Rotary encoder has some level of de-bounce resistance

Issues

  • When heating up fast sometimes the controller reboots (19V 4,5A laptop PSU)

Resources

Credits

Buy

  • Bare PCB: 3€

Notes and preferences

  • Atmega 328p MCU is very familiar for electronic hobbyist and Arduino support is good. Unfortunately this MCU is hard to source since 2022.
  • Eagle EDA free version for small projects is also very familiar for hobbyists and it’s file format is supported by many other packages.
  • JBC T245 iron is not as popular and cheap as Hakko T12 but the availability of handles and cartridges in EU is better. The maximum power is greater and internal resistance is lower.
  • Display, rotary encoder and socket for iron are on the same side of the board so that the board can be mounted on front of the box while PSU and power cord are on the back side.
  • P-FET on high-side is easier do drive but the efficiency is typically lower than on N-FETS.
  • N-FET on high-side needs a charge-pump circuitry to drive and while the N-FET itself has typically better efficiency the charge-pump is/seems to be not very efficient (diode and resistor gets hot)
  • DC-DC step-down converter allows greater input voltage range (48V with TD1466)
  • Single channel Op-amp is used to avoid extra resistors needed for two channel op-amps on the channels that are not used.
  • Series resistor and reverse diode on the input of the Op-Amp are used for the protection against possible voltage spikes from the iron.
  • Large ceramic input capacitor is smaller than electrolytic capacitor with same values would be but the ceramic capacitor “sings” audibly 
  • Parts are available either in EU (TME or Mouser) or China (LCSC).

TaaraESP SHT21 USB Wifi Temperature and Humidity sensor

August 20, 2021 |   |  Comment  |  Wifi

Next version of the Wifi Temperature and Humidity sensor with ESP8266 ESP-12S Wifi module and SHT21 digital humidity and temperature sensor with additional USB interface. The board has on-board 3.3V regulator and can be powered from USB charger with USB-A socket. Deep sleep function is supported for ultra low power mode. There are also an on-board status LED and a PROG button for entering the program mode (hold down while power-up). The board is now equipped with the serial to USB converter chip to make flashing and monitoring the sensor more convenient. Temperature and Humidity sensor is located away from other components and separated with cut out slot for better thermal isolation. The board dimensions are designed to fit the off-the-shelf enclosure.

Features:

  • Wifi module: ESP8266 ESP-12S
  • Digital humidity and temperature sensor: SHT21 or HTU21D
  • Supply voltage: 5V
  • USB serial interface: CH330N
  • Only TX/RX serial signals are connected to USB
  • DTR signal is not connected to USB
  • Program button
  • Status LED
  • Deep sleep function: supported
  • Home Assistant integration: ESPHome
  • Pins
    • LED: 13
    • SDA: 4
    • SCL: 5
  • Optional enclosure: Multicomp 1603603

Resources

Buy

  • Bare PCB: 3€ 
  • Pre-assembled: 37€
  • Full set 42€ 

Triple Base for WeMos

August 20, 2021 |   |  Comment  |  Tools, Wifi

Triple base board for popular WeMos D1 (ESP8266) and WeMos S2 (ESP32) microcontroller boards and shields. Base board is designed for WeMos D1 boards but there is enough room on the sides to mount WeMos S2 with selected pin headers. There are prototyping areas between the double signal and power pins and rows of power pins (GND, 3.3V, 5V) on the bottom part of the board.

Features

  • Compatible with WeMos D1 (ESP8266) boards and shields
  • Partially compatible with WeMos S2 (ESP32) boards
  • Prototyping areas
  • Extra ground and power pins
  • Mounting holes
  • Headers are not included

Resources

Buy

  • Bare PCB: 5€

FTDI RX/TX Opto-Isolator

January 14, 2019 |   |  Comment  |  Tools

Simple Opto-Isolator board with only two channels to isolate RX and TX on UART communication lines. Both sides have FTDI style connectors but only GND, VCC and RX/TX are used. CTS and DTR are not connected. Also both sides need to have a separate power supply.

Features

  • FTDI style headers on both sides
  • Two channels – one in each direction
  • Speed up to 9600bps
  • Both sides need a separate power supply

Resources

Buy

  • Bare PCB: 3€
  • Pre-assembled: 10€

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€

 

1-Wire Temperature, Humidity and Light Sensor

November 20, 2016 |   |  10 Comments  |  1-Wire

1-Wire Temperature, Humidity and Light sensor uses one DS2438 1-Wire chip for three different measurements. This board is very similar to the 1-Wire Humidity and Temperature Sensor – even the board size is the same. The only difference is added BPW 35 S photodiode from Osram and the current sense resistor for light level measurements. The actual calibration (if needed) should be done in the software or by replacing the current sense resistor (default 4.7k 1%, before nov 2018 it was 240Ohm).

Features

  • 1-Wire device: Maxim DS2438Z+ ADC with internal 13-bit temperature sensor
  • Humidity sensor: HIH-5030
  • Silicon PIN Photodiode: BPW 35 S
  • Supply voltage: 2,7-5,5V DC
  • Wiring on the full set model with the RJ12 plug (compatible with Maxim DS9490R USB to 1-Wire adapter):
    1 – VCC 5V (yellow)
    2 – NC
    3 – OW 1-Wire data (green or blue)
    4 – GND (red)
    5 – NC
    6 – NC (black or none)

Resources

Buy

  • Bare PCB: 3€ 
  • Pre-assembled: 52€
  • Full set: 57€ 

NB! The price of main parts has increased significantly due to the chip shortage. Our prices are adjusted accordingly.

 

TaaraESP THBL Wifi Temperature Humidity Pressure and Light Sensor

November 18, 2016 |   |  Comment  |  Wifi

Evolution of TaaraESP SHT21 Wifi humidity sensor with added pressure and light sensor. The LED and programming header work the same way as the previous model. Regulated 3.3V and GPIO2 are now available via unused pins on the programming header.

Features:

  • Wifi module: ESP8266-7 or ESP8266-12
  • Digital humidity and temperature sensor: SHT21 or HTU21D
  • Absolute Digital Pressure Sensor: MPL3115A2
  • Ambient Light Sensor: TSL2561
  • Pressure range: 20kPa to 110 kPa
  • Supply voltage: 5V
  • FTDI 0.1″ locking header for programming and debugging
  • UART logic level: 3.3V
  • Program button
  • Status LED
  • Deep sleep function: supported
  • Pins
    • LED: 13
    • SDA: 2
    • SCL: 14
  • Optional enclosure: Multicomp 1603603

Resources

Status

  • Waiting for boards
  • Not tested

1-Wire Passive 5-port HUB

November 12, 2015 |   |  Comment  |  1-Wire

A simple 1-Wire Passive 5-Port HUB with five RJ-45 sockets connected in parallel on a small board with two 3 mm mounting holes, black soldermask and white numbered labels.

Features

  • RJ45 sockets: 5
  • Type: parallel
  • Panelization: 4 boards on panel, not v-grooved

Resources

Buy

  • PCB panel: 10€ 
  • Pre-assembled: 15€