PosterBot: Make a Marker-Writing Robot out of an Old Inket printer and an iRobot Create

Step 2 Making the control board and configuring the serial cables

Here we're going to make the control board. This board will control turn both motors on and off and control their directions with signals from the command module.

The ports will be as follows:

PC5 (top center pin 1) - motor 1(carriage) on/off
PC1 (top center pin 2) - motor 1(carriage) direction

PC4 (cargo bay pin 1) - motor 2 (maker) on/off
PC0 (cargo bay pin 2) - motor 2 (marker) direction

Top center pin 7 - motor 1 supply
Cargo bay pin 7 - motor 2 supply
Top center pin 4 - +5v
Cargo bay pin 5 - grnd

You'll need to strip the serial cables and use the multi-meter to determine which colors go with which pins. Remember: Pin 1 is the top left pin on the female command module.. this means it will be the top right pin on the male serial cable

To make the control board you will need the PC prototype board, the relays, diodes, transistors, resistors and jumpers.

4 PC-Mount DPST 5v DC relays rated at least 1A
4 2N222 Transistors
4 1k 1/4 watt Resistors
4 1N4003 Diodes

RadioShack usually won't have everything. Look for a local electronic supply store or try

DIgikey
or
JameCo

Mount and wire the components according the schematic. I got this schematic from Robot Builders Bonanza 2nd edition
I guess there is a third edition now, but I'm not familiar with it. I highly recommend the book for anyone looking to continue building robots.

This next bit is going to sound like obvious advice but, remember that you want the leads of the components going through to the copper side. I made the mistake of setting up almost the entire board before realizing it was upside-down.

The colored cables you see running away in the photos are the serial cables that correspond to the various pins. I used hot melt glue to attach them to the board to lessen the strain on the solder joint.

I've added picture of my board so you can get an idea how to add them