Core3duino using arduino

This is an addon shield to an addon shield. That’s right, you have to have the Core2duino on your Arduino to be able to understand why you would want this in the first place. So once you have your Core2duino saddled up, give this one a shot (you don’t technically have to have the core2duino to use this with your arduino or standalone, but only pins that are plugged in will work).

It will fit on any Arduino (including Mega) and allows for an additional shield to be added on top (shield will be connected to the base Arduino) other pins will be free.
It can be powered via the Base Arduino or the VIN pins – power will be routed through the VIN pin from base Arduino and back out as +5v to Core2/3duino.

Why do this? well, the short answer is – why not? You end up with:

3 separate processors
60 input/output of which:
24 digital I/O pins
18 pwm pins
18 analog inputs
including 6 external interrupts

…all for about $25 more than your Arduino. (about $10-12 each)

Anyways, it only took about an hour to modify the Core2duino Eagle file into this.

This is a fun project to try and the .brd file has adequate spacing for ease with etching.

Most of these instructions are very similar to the Core2duino… differences are noted.

I will be happy to help if anyone has questions.

The next version is likely to have an FTDI programming cable connection for easy in system programming.

Step 1: What you need to get started


1. (1)pc copper clad (3″x4″) or assortment
2. (1) 28-pin dip socket
3. 16 mHz crystal resonator w/ built-in capacitor
4. An Atmega168 with Arduino bootloader
5. (2) stackable header set
6. (2) 6-pos female headers (2) 8-pos female headers .1″
7. (4) male pin headers (optional) .1″

Other things needed:

power LED, any size/color
330 ohm-1k ohm resistor for power led
10k resistor for reset button
reset button
.1uf capacitor optional
16v 22uf-220uf capacitor optional

etchant solution (muriatic acid + hydrogen peroxide)
paper towels
scotch brite pads
Laser Printer
magazine paper
rubber gloves
aquarium bubbler


Step 2: Download and print the Eagle file

You need a Laser printer. Don’t try it with an Inkjet as it will not work.  I have heard bad things about Brother laser printers using strange toner that doesn’t transfer to copper, but I use a Brother 7020 and it works great. I have tried several different types of magazine paper and i’m sure that most will work, but if in doubt, use Cosmopolitan.

1. Download the  .zip file and EagleCad if you don’t already have it.
2. Unzip the .zip file to your computer.
3. Open the .brd file with Eagle.
4. Select the “Layers” option and de-select the “top” layer, leaving the other options as they are.
5. Select Print, make sure you check the boxes “Black” and “Solid” under Options. Then Print to magazine paper.

Carefully cut the printed design to the size of your copper clad. Use a razor blade or scissors, just be sure not to touch the toner with your fingers.


For more detail: Core3duino

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