Project: My TTL clock

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Joined Jul 31, 2009
Well it's not completely done but before I rip up the solderless breadboard and go to soldering I wanted to put it up here. I've never really done electronics before although I built some kits, Dynaco and Heathkit when I was younger. A couple years ago I was buying stuff at the local flea market, like student stuff. Now I am unemployed/retired I set out to build a clock from stuff I had. That was the rule and I mostly stuck to it. There are three attachments.

1) the breadboard, left top is the 1Hz source from a broken wall clock that had used a AA battery, below that is the three buttons: reset, hours, and minutes. The main part has the 7805 regulator at the bottom left, most of what you see is the heatsink. Above that is the 10 segment "bargraph" and counters. The middle is the 7490/74390 counters and 7447 segment drivers. On the right is the 4 digits of display. (11:01).
2) The logical schematic from the Hades tool. The "nines" button was not really used but seemed to make the simulation work better.
3) From eagle CAD the buttons and 1Hz clock schematics. These can be thought of as feeding the inputs on the left side of the Hades schematic.

Hope this all uploads correctly. I've learned a lot from this site and wanted to contribute. Any comments on the circuits are welcome, but remember some of those weird things may be due to my rule, have to use what I have.


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