DIY clock based on 4000-series logic ICs

Terry built a LED bar display clock using only logic ICs:

Although I’m way too late for the 7400 contest, I had built a chips-only digital clock from 4000-series IC’s The time was displayed by columns of LEDs i.e. first columnt was 1-12, and the led for that hour would be lit. The next column was the tens-of-minutes (0-5), and the last of course the minutes (0-9). I used a whack of 4029’s, 4514, 4017’s and whatever else I had around, and tapped a transformer for the the 60hz. In one of my earliest attempts at PCB making I made the 3-column LED display. It was at that time the most complicated logic circuit I had ever built, and I was rather happy that it worked! I ran it in my workshop for about a week and it kept time really really well. So in the spirit of ‘what can you build with only logic chips’, humbly give you my strange creation

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2 Comments

  1. That’s great — the whole scene looks very retro. The quality of the picture, the power supply, the Turbo C++ box in the background. Are you sure that picture isn’t from 1985? I love it!

  2. my horrible photography was based on a glorified Wal*Mart $27 “Digital Camera” (my very first circa 2004-ish) No flash, and definitely not megapixel! If the batteries died so did the volatile ram memory, and you lost all your pictures. But I’m quite certain that my CMOS 4xxx chips are more than likely 1980’s vintage. I hadn’t done anything with the hobby for 20 years, until I dusted off a few breadboards, and started plugging in wires. Took me a week to figure out why my time would go haywire, I need some pull-down resistors on some of my clock signals, noise was screwing it up. After then, even this breadboard mess was solid for weeks. Now everything is micro…

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