MaxDuino

Is a small PCB carrier board that acts as a host for an Arduino NANO. The PCB provides a multitude of supporting features for the NANO. It is targeted for use as a model railway animation tool (see feature list) Because of its flexibility it can be used in many different scenarios.

There are two current versions according to needs:

R1.6 uses RJ-45 jacks (network patch cords) for power and communications

R1.4 uses screw terminals for simple wire connections

Key Features

Arduino Nano R3 is fully utilized.

On board NeoPixel for flexible diagnostic use and status reporting.

Robust on board DC power supply (5V DC, 9-15V DC/AC, or DCC)

DFRobot MP3 player with SD card and speaker terminals

Lots of 3 pin headers and an I2C header

Opto Isolator for decoding DCC packets

A RJ45 jack is used to connect 12VDC power and RS485 signals between R1.6 boards

Two sets of jacks are provided for easy daisy chaining

The MAX485 chip has seperate DE/RE pins allowing ICSP of the Arduino.

Sample sketches for testing, and to accelerate your own development.

Detailed build instructions are provided in Excel.

Status of MaxDuino development

Rev 1.6 Is The Latest RJ45 Version

No functionality differences vs R1.5. Minor improvements are:

Improved spacing around votage regulator for heatsink mounting

Added stencilling around 5 volt terminals indicating polarity

Brought the preamp pins on the Mp3 player out to pads (some people uae external amps)

Since the R1.4 version

The previous screw terminals for RS485 have been replaced with RJ45 jacks.

The power supply section received a major redesign.

The round bridge diode is replaced with 4 discrete diodes.

3 additional diodes are used to drop the input voltage into the L7805 regulator

A diode has been used to prevent backfeeding power onto the network cable (Substitute a jumper where feeding power out is the desired behaviour)

Screw terminals for a speaker are deleted. (Now using 2 pin headers)

Remote power and RS485 coms tested via a standard network patch cable

The full test suite has been run and all testing passed successfully.

Known Issues

None

Rev 1.4 Is The Latest Version using screw terminals

This version is electrically the same as Version 1.3) however the

silkscreen errors have been addressed

All functional testing passed successfully.

Updated test sketches provided. Test code reflects correct pin assignments,

Sketches are simplified and compartmentalized as to their the test scope.

Rev 1.3 and Older Have been removed from GitHub (Files are in the archive)

MaxDuino KiCad files including GERBERS.

The KiCad files are essentially 'source code' and include:

the schematic and

the Printed Circuit Board art work The Kicad software checks for consistency between these two.

The Gerber files can be thought of as the 'compiled version'. The Gerbers are seperate files, one for each step in the manufacturing process of a PCB. The Gerbers are normally saved as a ZIP file and the Zip file is what gets submitted for manufacture at the fabrication facility of your choice.

The Panel Version

The MaxDuino PCB is sized 50 mm x 100 mm which means it can easily be panelized in sets of two. This makes the panelized Maxduino fit on a single 100 mm x 100 mm PCB which is the normal 'minimum size' for billing. The short version of this is you get twice as many MaxDuinos at no extra cost.

There is a seperate folder containing the Panelized version of the Gerbers.

Be Aware

Normally all EDITS should be done to the 'single PCB' and then it be repanelized To repanelize you start a new Kicad project (one with no contents) and run a 'plug in' to panelize things. You will specfiy which other file has the PCB layout you want to panelize. You also set the number of rows (2) and collumns (1) The only manual step needed is to add a horizontal line on the edge cut layer. This will be a 'Vee-Cut' and allows separating the two PCBs easily.