Single chip for digital clock. - Page 1
Forum section: electronics / beginners

author: SylvainP
author_rank: Contributor
timestamp: August 29, 2015, 09:03:05 pm
content: Hello all, I'm new here and was not sure where to put my question. I'm a newbie here but started in electronic in the 1970's. But I'm relatively inexperienced because I left the hobby for computers in the 80's. I did not throw away my equipment and parts and continued adding to it from time to time because I did want to come back to it one day. That day came when I had to stop working for medical reasons.This place needs a forum where new member can introduce themselves but maybe this is it? (or did I miss it?)Anyway, my father recently told me that he can find a 24 hour alarm clock, i.e. one that display 14:00 instead of 2:00 with an AM/PM indicator. So thought to myself I could build him one for his birthday in December. I could do it easily enough with discrete logic chips or a microcontroller but it seems to me that someone must make a chip that does it all already. So, does such a beast exist?Thanks in advance.P.S. English is not my first language.

author: carcanhol
author_rank: Regular Contributor
timestamp: August 29, 2015, 09:09:56 pm
content: Hope this helps, i'm no pro eitherhttp://www.decodesystems.com/clock-ics.htmlhttp://www.paulanders.com/G5-LED/ver1/datablad.pdfhttp://www.electro-tech-online.com/articles/pic-single-chip-4-digit-24-hour-clock.678/Also:Search for LM8560 in google then images.

author: SylvainP
author_rank: Contributor
timestamp: August 29, 2015, 09:26:20 pm
content: Thanks carcanhol, the LM8560 seems like a winner.

author: edavid
author_rank: Super Contributor
timestamp: August 29, 2015, 10:30:57 pm
content: If you don't want to build one, you can look for a ham shack clock:http://www.eham.net/reviews/products/61This one seems like a good choice:http://www.mfjenterprises.com/Product.php?productid=MFJ-113

author: SylvainP
author_rank: Contributor
timestamp: August 30, 2015, 05:04:58 am
content: The LM8560 seems obsolete, I could only find it on ebay. I checked digikey, mouser, and a couple of local places and none have it. If the clock was for me I wouldn't mind but since it's not I want something I can easily fix if.Quote from: edavid on August 29, 2015, 10:30:57 pmBookmarked just in case thanks.Quote from: wilfred on August 30, 2015, 12:26:52 amThank you.I'm not sure yet if I'm going to go with LED or LCD but I'm not going for a fluorescent display for the same reasons I just gave at the top, I do not want to go with obsolete hard to get parts.

author: SL4P
author_rank: Super Contributor
timestamp: August 30, 2015, 06:16:46 am
content: Sorry about the schematic style - I just wanted to capture it at the time - very simple.PIC 16F628 + Maxim DS-3231 + SURE Electronics DP-002 4x7 LEDThis is as simple as it gets - with the benefit ofLARGE DIGITS(for old guys like me) !Cost is minimal - running on perfboard from a DC plugpack. (was cheaper 5 years ago!)n.b. 7805 regulator is not shownHolds time really well (DS3231) plus a Supercap to carry across blackouts.Decent LED segments that don't dim/or fail like retail chinese crocks.The PICC-C code is ugly, but it has been working for a few years now - I just wanted a clock that I didn't have to re-set or replace every 2-3 years !An alarm could be added, but I didn't need one at the time - a good starter project for some.Display is 24-hours, but could easily be re-coded for 12/24hr operation.http://store.sure-electronics.com/led/led-display/de-dp23711Source for IM if you're interested.

author: edavid
author_rank: Super Contributor
timestamp: August 30, 2015, 03:22:56 pm
content: Quote from: SylvainP on August 30, 2015, 05:04:58 amThe problem with that is that *all* dedicated alarm clock chips are obsolete (except maybe China-only parts that you won't be able to get).

author: picandmix
author_rank: Frequent Contributor
timestamp: August 30, 2015, 03:46:56 pm
content: There is not that much difference between a micro and a ready made clock chip, which as you are finding there are not many around these days as its so easy to incorporate a rtc into most micros.This link has a very easy to build micro led clock and he has a few others clock projects with extra functions or big displays; think it would be a much more interesting project for you.http://bogdi.ro/electronics/digital%20clock/

author: bills
author_rank: Frequent Contributor
timestamp: August 31, 2015, 12:55:46 am
content: I got one of these for my grandkids to build works well.http://www.ebay.com/itm/DIY-LED-C51-4-Bits-Digital-Electronic-Clock-Suite-Production-Kits-Parts-/141682975468?hash=item20fcf6a2eccorrection it was this one.http://www.ebay.com/itm/DIY-AT89C2051-6bits-Digital-LED-Electronic-Clock-Digital-Clock-Kit-/181525540222?hash=item2a43c3ed7e

author: SylvainP
author_rank: Contributor
timestamp: September 01, 2015, 01:16:48 pm
content: Quote from: SL4P on August 30, 2015, 06:16:46 amThank you, I have decided to go the micro-controller way after all. I do want to design my own clock but that does not mean I can't take inspiration from what other people have done.Quote from: edavid on August 30, 2015, 03:22:56 pmYou seem to be right, micro-controller it is then.Quote from: picandmix on August 30, 2015, 03:46:56 pmThanks for the link, I want to design my own but other clocks schematics are a good source of idea for what parts to use, specially for the display and the 1 Hz source.Quote from: bills on August 31, 2015, 12:55:46 amWow, this is really cheap. If I did not want to design my own then I'd surely pick this one. If my god-son was still a kid then that would have made a great gift. Heck I might end up getting it just for the parts.

author: picandmix
author_rank: Frequent Contributor
timestamp: September 01, 2015, 01:52:16 pm
content: You need to address the hardest part of the design first - is it going to be mains or battery powered and then finding a neat case for it all the fit into.