INTRODUCTION

The details on how to put together a Fabduino board are outlined on Ed Baafi's HTM page from 2010.  This guide will walk through some of the troubleshooting steps you will most likely go through in the process of making a Fabduino board.

A finished Fabduino

MILLING THE BOARD

The workflow for cutting out your board is as follows:

• cut out the traces using the 1/64" endmill (traces file)
• mill out the holes using the 1/32" endmill (holes file)
• cut out the board using the 1/32" endmill (or optionally, cut out the board using the angle shears in the CBA shop) (cut out file)

Some things to watch out for when milling:

• Use a single sided board! Otherwise, you might short your input pins when you solder on female headers.
• Use 3 strips of double sided tape on the back of the board and ensure that the board is securely taped to the Modela cutting bed.
• Make sure you're on the right setting in the Fab Modules (mill traces vs cut out board)
  
• Check that the endmill isn't dull - if it is, switch to a new endmill
• Ensure that you've zeroed your endmill
• Watch the Modela for at least the first few minutes of the job to ensure the board doesn't get removed from the cutting bed.
• Debur your board when you're done using a razor blade.

It takes about 25 minutes to cut out a board completely from the Modela, so budget your time accordingly!

If you need to cancel a job, follow the instructions on this page under "How do I delete my job."  You will need to enter the following commands into the terminal:

ps -aux | grep cat

kill xxxx 

Also, be careful of sanding your board in the shop. I used the circular bandsaw and cut my board in half!

STUFFING THE BOARD

Before stuffing you board, I recommend checking your traces with a multimeter.This involves using the continuity check mode on the multimeter, which is usually indicated by an audio symbol:

• Turn the dial to the continuity check mode
• You might have to hit "mode" to ensure that you're in the continuity mode. You'll be able to tell by the little audio icon that appears on the screen (on the top right)
• Touch the black and red leads together and make sure you hear a beep. Then you know that you're in the right mode.

Go around your Fabduino board and check that none of the pins on the perimeter of the board are connected to one another (meaning the pins labeled in the diagram below).

If they are, take an xacto blade and run along the edges of the traces to remove any extra copper.

This picture will become your best friend

After you're done checking, go ahead and solder your components onto the board. Here are a list of parts you will need for your board:

You can check where the components go by referring to the Eagle files (board + schematic). As a reminder, if you open up the brd file, you can type "info" and then click on any component in the layout, and it will open up a properties file with the component name and value.

Using the flux pen

Do it! Use a flux pen to add flux around all the itty-bitty microcontroller pads on the board.  Then apply solder, and it will flow nicely without clumping up. If it does, just use solder wick to remove the extra solder.

DEBUGGING

There are a few things you should do to test your board before even trying to program it.

1. Use a microscope to check that none of the pins are soldered together accidentally.
2. Use the multimeter again to check that none of the input pins are connected. You can do this by checking each pair one by one.
3. Connect the FTDI to USB cable to your board. Is your microcontroller getting 5V across the VCC and GND pins? Again, check the Eagle brd file using "show VCC" and "show GND" to check which pins are VCC and GND. Set your multimeter to the VDC mode to check the voltage drop.
4. Are the VCC and GND pins shorted to one another? Use the continuity mode to check if they're shorted. If they are, you need to carefully check that you don't have extra solder connecting pins, or you can use the razor blade again to go over the traces.
5. Check that the input pins are connected to the right pins on the microcontroller.
   

PROGRAMMING THE BOARD

To program the board, you need to make a connector that connects the programmer header pins on the FABISP to those on your Fabduino. There are many ways to do this. I used two different ways (for different boards I made):

You can solder male headers to the end of the ribbon wire and connect those to the female headers on your board. Or you can solder them directly to a row of male headers, making sure that the order matches that of the Fabduino board.

You need to check that the MISO, MOSI, etc line up on both boards:

Programming pins on the FABISP board

Programming pins on the Fabduino board

The steps for programming your board are nicely outlined on Ed's site, so I won't repeat them here.

If you get an error in Arduino about checking your connections, go back to the debugging section of this page to run through the steps of checking your board.

When you're done, you should get a message that looks like this:

Congratulations, you have a Fabduino!!