Just Fooling Around with Logic..... don't tell my Wife!

It's Friday night and my wife and girls (a 4year old and 20month old) are off visiting relatives and I am trying to work out some concepts for my entry into the Open 7400 Series Logic design competition.....

I thought I'd just start with the basics and work my way up. Every Logic based design needs a clock, so I started out building up a 1Hz Ring Oscillator with a 74HC04. (The LTSPICE Yahoo Groups had this great Ring Osc. circuit which I used as a starting point).

Then I thought using a 74HC90 BCD Counter to drive a 74LS47 BCD to seven segment driver would be a fun way to use a 1Hz clock.... pretty Digital Logic 101, but hey I need to start some where.

So here is the first "Brain Storming" part of my entry:

Much more circuitry and trickery to come before the deadline!