I've lobotomized myself trying....

[captainkirksdog]

Hello,
I've lobotomized myself trying to build this project. So, can anyone come up with a reliable schematic for a 24-hour countdown clock? Exactly what I need is as follows:

Programmable keypad time entry with Start/Enter button
6-digit LED display
CMOS Logic-level alarm output
Using Standard 4000/4500 Series CMOS I.C.s
9-volt battery-powered
Accuracy +/- 1 minute

Basically, a 24-hour LED egg-timer. I'm fairly certain that this could be done using a PIC or a micro-puke, but I know ZIP about them. I don't want to go that route. Unless there's something like this I could buy. Besides, I already have most of the CMOS chips.

Since I royally suck at circuit design, any help, tips, advice or criticisms, will be entertained. (Even PIC-type stuff as long as it has all the info about programming data and hardware)

I appreciate your time and I look forward to your replies.

Thank you. <ckd>

 

[Reloadron]

If you want to go with discreet components you could **broken link removed** using a 4510 & 4511. The accuracy will be as accurate as your clock for what you are looking to do. You could use dip switches to program the 4010 (Programmable up/down counter) or in your case 4010s because you would use 6 EA of them. They would be cascaded for HH:MM:SS. Anyway, the link may help and there are also other ways and other chips that could be used.

Ron

 

[blueroomelectronics]

Well I know you're not interested in the microcontroller route but I've posted a complete 6 digit clock design with source code in my Dragonfly kit manual. The microcontroller route isn't so bad.

 

[Reloadron]

Well I know you're not interested in the microcontroller route but I've posted a complete 6 digit clock design with source code in my Dragonfly kit manual. The microcontroller route isn't so bad.

Being new here I see so many post where people just want to shy away from the use of a uC and I don't understand why. Once you learn some basics about them they quickly become the best thing since sliced bread. Even though I am far from good with them I find myself learning more and using the little creatures for all sorts of applications making assembly so much easier.

I think the reluctance is just the getting started phase and understanding micro-controllers a little better.

Just for the original post in this thread using the link I provided the OP will need 6 programmable up/dn counters and 6 display drivers. Then a stable clock plus other chips. All of that and more to keep it using discreet components.

I haven't seen your 6 Digit clock design but have looked at several of your designs and learned quite a bit. Hey, lurking has its merits.

Ron

 

[Vizier87]

everyone should start with uCs if they wanna start with electronics nowadays.
It's a package deal. A very good one.

 

[captainkirksdog]

Some explanations

Hello.
I "started" in electronics 40 years ago. Most PICS and 'pukes that I've seen are surface-mount and are just to damn small for me to see anymore. And, like I said, I already have the discrete stuff, but not one piece of PIC gear. No cables, no "burner", (or whatever they call them nowadays), and no way to make a PC board for one. I know there are PCB houses that do one-offs, but I would still have to route the circuit. So, I'm just not interested in doing it in software. I could very well be wrong about not using code to do this, but I don't have a clue where to start. I'm definitely NOT going to start buying a bunch of books or kits or whatever just to do it "easier". I'm hoping some of the "old geezers" out there like me can come up with something. I know it can be done the way I want, after all, NASA did it back in the '6o's with vacuum tubes and relays. Remember the huge countdown clock at every launch? I do appreciate the feedback though, please don't think I don't. I guess I'm just a dinosaur. <ckd>

 

[Pommie]

Hi Jake (or kirks dog),

Pics are available in through hole packages and I build prototypes on breadboard. The software is mostly free and the hardware programmers are around $35.

Here some I made earlier, .

Edit, I also started in electronics 40 years ago.

Mike.

 

[Reloadron]

Well if PICs are out then I suggest you look ay my first post using discreet components. They use a 4510 & 4511 plus a few other chips but all discreet. If you want another option you could look towards using a series of cascaded 74LS192 TTL family counters. Set them up to count down and let them directly drive 7447s.

I can understand the case of wanting to shy away from uC chips. I recently turned 60 myself and started my life in trons at 13 with my first amateur radio license. Where I have worked for many years most of the older senior engineers have no desire to advance to the newer technology. As they retire and are replaced by recent grads the only thing the new kids want to use is PICs. As for me it matters not, darn visual acuity isn't what it once was but I do like the new stuff.

Ron