Saturday, March 14, 2015

Overview

I made this clock to satisfy two requirements; to build something that uses the i4004 microprocessor and to have a appropriated device to celebrate my retirement. 

I have spent most of my career using microprocessors, designing circuits around them and programming them using assembly code and higher level languages but I never designed with them at home. I did design and build a Tic-Tac-Toe game using a i4004 but it was a mostly more modern circuitry surrounding the i4004. This clock is mostly period correct through and through, well, except for the non-red LEDs and Nixie tubes.

My first exposure to the i4004 was at Melpar, E-Systems. I was part of a small team to design a digital intercom system to be used in the U2R collection system ground stations. The ground stations had several operator consoles where operators needed to communicate with each other, operators in other shelters, and with the U2R pilot. The i4004 in these intercoms controlled the connections between these operators and some cases blocked connections.

So, I guess, many years later near and for my retirement I wanted to go out with a bang. This is why there is confetti cannon in the design. The plan was to have the clock count down and fire the cannon at the second I retired, at work. To meet the security requirements because I worked in a SCIF the clock had to have a model number and serial number. No problem, I just added those two to the cannon control output plate in the back. Then I found out that security would not let me bring in a cannon into the SCIF. Rats. Well, it all worked out as I planned to retire in the middle of our Christmas vacation when no one was at work anyway so I ended up just making a video of the last few seconds on 12/31/2010: 



Here is a link to the design document: Mini_Block_V7.pdf

Here is a all the code: 4004 Code