A small but useful side project that started as a ground base for the crane.

The crane has an Arduino Nano with Wii Nunchuck and one motor on the ground. Initially it was a breadboard with jumper wires, but then I thought that the project needs a proper PCB on the ground. Along the way I realized that an Arduino with motor and some other connectivity options would make a useful PCB on its own, and so this project was born.

Board render and schematics

Features

  • Arduino Nano socket with all the pins broken out

  • Wii Nunchuck connector on the side

  • socket for DRV8833 dual DC motor driver board, along with 2 2.54mm and 2 1.27mm motor pin headers

  • 4-pin I2C socket, designed to fit a 0.91 128x32 OLED display

  • 2 buttons (routed to D4 and D5)

  • convenient project-related sockets for connecting analog and digital pins:

  • GND-A0-5V, GND-A1-5V and GND-5V-A2

  • GND-5V-TX-RX (UART)

  • GND-5V-D3

  • cuttable jumper to connect motor input to VIN (instead of 5V)

  • size is 50x75mm

Wii Nunchuck is a 3.3V device, but all aliexpress arduino adapters just use 5V and everything seems to work fine. I made the connector powered by 3.3V, but it’s possible that data pins (I2C) are 5V. There are places for I2C pullup resistors (0805 SMDs) on the PCB, but the components seem to already include these pullups, so both the Nunchuck and OLED display work fine without additional pullups.

Showcase

The PCB is now used in 3 projects.

Projects photos

Tachometer

It has an optical sensor (which I salvaged from a printer) that is interrupted by a spinning motor, arduino calculates RPM and shows it on an OLED display.

DC motor tester

Very simple project that reads a potentiometer and sets PWM for a DC motor. Allows to spin the motor in both directions.

I use it to quickly animate motors installed into projects without writing complicated firmware.

Portal crane

The board reads Nunchuck data, controls one motor to move the whole crane and sends UART commands to PCB inside the crane. Crane PCB is detailed in its own dedicated project "motorboard" page.

Project can be viewed in online IDE here: https://oshwlab.com/positron96/motorboard. It is published under CERN Open Hardware license.

The PCB was designed in EasyEDA Pro as part of the crane project, so it is called "host" in "motorboard" project.