At long last, I have a memory keyer. It was about four years ago, as near as I can tell, that it occurred to me that, not only was constructing a memory keyer based upon the Arduino a good idea, that it was sufficiently obvious that someone else must have done it already. That meant I could leverage their code and hardware designs to that end. After I found K3NG's design and and software, I decided that this project would make a good introduction to PC Board layout and good practice for surface-mount construction. Almost two years ago, I had accumulated printed circuit boards and a box and jacks and a display and an Arduino and all the various pieces and got it to a state where it worked, more or less. The "more or less" had to do with the fact that the PTT lines weren't always being keyed when I expected them to be, and after taking the device apart and putting it back together a few times (and blowing up the Arduino I had) I decided to start over and connect the switches, jacks, and so forth to the shield with longer wires.
Along the way, I discovered that ScotchBrite really does make it easier to solder by scrubbing the tarnish off the copper and many of the myriad ways of screwing up a crimp-on pin. But, I'm far enough there that I can declare it done. I destroyed one of the pushbutton switches during the rework and I think I need a 1K pot instead of whatever I'm using, but it keys the radio and the speed is adjustable with the keyboard. I'll get another pushbutton, so I have access to all twelve (12!) memories, and I have another potentiometer to use for the speed control, but it's basically done. Just in time for the CW half of the CQ WPX contest, too.
I want to make some changes to the source code (I'd rather have the keyer status be on the top line of the display rather than using all of the display to show what was sent and I think it would be cool to use two of the front-panel buttons to control the speed) and I've discovered that the source code is, um, not perhaps as pretty as one might like. I'm looking in to making some modifications. We'll see how that goes.
Anyway, I'll try to keep people updated as to how things are going.