Like just about every young engineer back in the Seventies I have built my own TTL clock. It's a mystery to me what has happened to it though. I can't remember scrapping it, and can't seem to find it anywhere either. Anyway, it wouldn't make a good project on this site anyway because I didn't design that project myself.
Let's move ahead in time to the present again. I used to have an alarm clock on my bedside table for years. However nowadays my wife has to get up first and now she has the alarm clock. Whenever I wake up in the middle of the night I have to raise myself in order to see what time it is on her side of the bed. So I would want to have a clock on my bedside table again.
I could have bought a brand spanking new one for a whopping €8 in a regular shop here in the Netherlands. But where's the fun in that? Why don't I build a clock myself again, like I did in the old days. It doesn't have to be an alarm clock, as it doesn't have to wake me because I use my smart phone for that. A simple clock will do.
I have a whole (toy) truck load of CMOS logic ICs in stock.
Most of them have been in there for more than 30 years now.
Isn't it about time to use some of them?
I could easily create a very sophisticated clock using a modern micro controller.
But that spoils the fun of making a purely digital clock.
So let's build a digital clock with plain and simple CMOS logic components.
There are surprisingly few similar projects which build a CMOS clock with 4000 series chips to be found on the internet. Hopefully this project gets a bit of attention and is built by many.
The project I present here explains everything there is to know about this neat little clock of mine. I haven't bought a single component for it. Everything came right out of my (scrap heap) stock. This is not entirely true, I did have to buy the pad board on which the project is built. So technically speaking, this CMOS clock still was cheaper than the €8 ready made one from the shop. And it was much more fun building it.
So jump over to the the hardware page if you're interested in a simple, purely digital, clock too.