Solution For Making 7 Seg. Clock - Page 1
Forum section: electronics / beginners

author: skillz21
author_rank: Frequent Contributor
timestamp: January 21, 2016, 05:07:44 am
content: I am looking for a way to make a 7 segment clock. Without arduino.. is there a certain ic or something that i can use to drive 4 seven segment displays? and an ic to keep the time. i need to display the time on the displays. I know that it would be much easier to just use an arduino but i don't want to.Thanks!

author: Skimask
author_rank: Super Contributor
timestamp: January 21, 2016, 05:27:07 am
content: Probably a mistake, but...http://hackaday.com/2013/10/29/an-overly-complicated-logic-chip-clock/

author: rdl
author_rank: Super Contributor
timestamp: January 21, 2016, 06:01:26 am
content: Here is a link where one that Dave made is discussed. there is a link to the video in the first post.https://www.eevblog.com/forum/blog/eevblog-801-how-to-design-a-digital-clock/Here is one that can be a wristwatch or you could use larger displays and a power supply and make a table version.http://www.oldradiobuilder.com/LED%20Wristwatch.html

author: MrSlack
author_rank: Frequent Contributor
timestamp: January 21, 2016, 07:08:08 am
content: 4060 oscillator/divider with a 32.768KHz watch xtal. Then you chain two 74HC390 dual decade counters off it so you have 4x 4 bit couters. Use diode logic (1n4148) to programming the resets so you roll over at 12/24 for the last pair of counters and 6 for the second. Then connect the 4x4 bit outputs from the counters into 74ls47 bcd->7seg and then into 4x 7seg led displays.To set the clock, add some buttons to short the earlier divider stages to the first counter input. Do one at 2Hz for 'slow set' and one at 32/64Hz for fast set.This was the lowest and therefore cheapest part count I could muster when I did this about 20 years ago. Total 7 ICs, 4 LED displays, a few caps, about 7 diodes and about 35 resistors, an xtal and a roll of kynarIf you buy 4x TIL311 displays you can lose 28 resistors and the 4 7447s. But they are wuite expensive even if they look cool.

author: skillz21
author_rank: Frequent Contributor
timestamp: January 21, 2016, 09:04:24 am
content: i forgot to add, is there a simple solution?

author: jeroen79
author_rank: Frequent Contributor
timestamp: January 21, 2016, 09:58:34 am
content: Quote from: skillz21 on January 21, 2016, 09:04:24 amSimple in terms of less parts: A microntroller.

author: MrSlack
author_rank: Frequent Contributor
timestamp: January 21, 2016, 10:41:28 am
content: Well more parts in one IC package...

author: rdl
author_rank: Super Contributor
timestamp: January 21, 2016, 10:56:26 am
content: Years ago, many of the semiconductor manufacturers used to make specialized chips that would contain most of the circuitry needed for a basic digital clock. I don't think they're made any more, but sometimes you can find them on ebay.Try searching for "clock chip"http://www.ebay.com/itm/Vintage-MK-50250-MK50250N-Clock-Chip-Mostek-6-Digit-LED-VFD-NEW-NOS-/291659130147http://www.ebay.com/itm/uPD848C-Vintage-NEC-DIGITAL-Clock-Chip-40-Pin-DIP-848C-D848D-NEW-LAST-ONES-/390120522414

author: skillz21
author_rank: Frequent Contributor
timestamp: January 21, 2016, 03:09:49 pm
content: is there any chance of using an attiny? or a few of them?

author: newbrain
author_rank: Super Contributor
timestamp: January 21, 2016, 03:26:25 pm
content: Quote from: skillz21 on January 21, 2016, 03:09:49 pmYes, and yes.You could even think of 6 ATtiny (14 pins at least) each taking care of one digit, plus another for clocking and control...But your OP stated "no Arduino", so µC based solution seemed out of scope.If you meant "without using the Arduino development environment and library", then any ATmega 328 based board (including Arduino) should provide enough I/Os to support 6 multiplexed 7 segment displays plus a couple of switch for control.It would be a good programming exercise, definitely not too complicated, even using direct register access.

author: skillz21
author_rank: Frequent Contributor
timestamp: January 21, 2016, 03:40:17 pm
content: guys, i am still thinking about what sort of design to use so feel free to tell me all your ideas. even if it concerns a microcontroller.thanks

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 21, 2016, 04:59:36 pm
content: If you are not constrained by your use or non-use of a microcontroller then it's easy... just use multiplexing and get a microcontroller to drive the segments...e.g.http://embedded-lab.com/blog/lab-11-multiplexing-seven-segment-led-displays/That's just a random example, any controller, AVR, PIC whatever would do.

author: klunkerbus
author_rank: Unknown
timestamp: January 21, 2016, 09:44:58 pm
content: Being *simple* likely depends on your ability to search for existing designs, hardware, and software. Are you wanting to develop your own circuit board, or build a clock by wiring together existing boards/modules? Are you trying to avoid writing firmware?I like the Arduino movement since it creates a lot of AVR processor boards that I can use for dirt cheap, even though I never run firmware using the Arduino libraries or built in the Arduino IDE.Everything I do is for a hobby. I want to focus on my application and not putting effort into a board design that I may only use once, and my retired eyes don't like a lot of intricate wiring. Tying functions together with an i2c interface makes it easy to hack together something like a clock using existing modules with minimal wiring.These days, an i2c-based DS1307 chip is commonly used for the real-time-clock (RTC) function. You can use a DS1307 chip on your own board design, or find any of several small prebuilt boards using one. I personally prefer the more precise DS3231 that I can set and forget.I have various clocks and time controllers using an AdaFruit Boarduino running my own AVR firmware, an AdaFruit chronodot RTC board using the DS3231, and an LCD display with an AdaFruit i2c-LCD backpack. For an LED display instead of the small character LCDs, I've thought about trying one of the AdaFruit alphanumeric i2c LED arrays like this red one -https://www.adafruit.com/products/1911. They have various size i2c-based 7-segment displays as well.

author: dadler
author_rank: Unknown
timestamp: January 21, 2016, 09:53:51 pm
content: MAX7219 + your choice of microcontroller

author: johnboxall
author_rank: Unknown
timestamp: January 22, 2016, 03:37:03 am
content: Quote from: skillz21 on January 21, 2016, 05:07:44 amI've got a couple of LM8560s around here if you want them.

author: MrSlack
author_rank: Frequent Contributor
timestamp: January 22, 2016, 06:45:22 am
content: Quote from: wilfred on January 22, 2016, 12:41:28 amInteresting circuit. Never thought of hacking a 4026 to do the job.

author: rdl
author_rank: Super Contributor
timestamp: January 22, 2016, 07:20:36 am
content: Quote from: MrSlack on January 22, 2016, 06:45:22 amWhat? I thought it was practically what they were made for.Quote from: TI Datasheet

author: MrSlack
author_rank: Frequent Contributor
timestamp: January 22, 2016, 09:41:51 am
content: Bad choice of words - consider hacking as in the "I hacked up this circuit" as in created something. Basically I never thought of using a 4026. I mainly use 74-series TTL and most of the combined decade counter/driver ICs are/were when I last looked, unobtainium.

author: skillz21
author_rank: Frequent Contributor
timestamp: February 14, 2016, 05:22:52 am
content: Ok, so one of the main reasons I posted this is because I have this 4 seven seg display panel. I'm not sure of the correct terminology but basically, when power is received to a segment, it turns transparent. I want to make a projector that projects the clock on a wall. so now I don't care if I use the Arduino or not, I really want to make this. so could you guys please point out a chip that I can buy? (preferably cheap because it will probably cost a lot of money to get a backlight because it needs to be strong (because this is a projector)). and could you find a lighting source that I can use? and a power supply for it?

author: skillz21
author_rank: Frequent Contributor
timestamp: February 14, 2016, 10:18:08 am
content: any advice guys?Thanks!

author: ali6x944
author_rank: Frequent Contributor
timestamp: February 14, 2016, 08:19:00 pm
content: see this would help:

author: ali6x944
author_rank: Frequent Contributor
timestamp: February 14, 2016, 08:21:38 pm
content: forgot those: