Driving Digital Clock

Status
Not open for further replies.
A

ahmedragia21

Member
Hi, im trying to make a big digital clock , each segment is described as in the picture , the problem is i know how to drive 7-segment displays using BCD to 7-seg decoder , but in the display for example 00:00 has more than 7 segments as shown , what kind of decoder should i use ?
 

Attachments

  • clock.jpg
    32.2 KB · Views: 175

hi,
Looking at the drawing, each digit has only 7 segments, the 'colon' dividing the hours and minutes is always ON.

Where are, the more than 7 segments.?

BTW, how are you going to display 21:00 hours.?
 
Last edited:
thanks for the reply ,
i mean of each digit it has 20 LEDs , how i will drive these all ? and i really didnt imagine they are 7 segment , how ? suppose number 8 is there , sure there are more than 7 LEDs will be driven ..
 
ahmedragia21 said:
thanks for the reply ,
i mean of each digit it has 20 LEDs , how i will drive these all ? and i really didnt imagine they are 7 segment , how ? suppose number 8 is there , sure there are more than 7 LEDs will be driven ..
Click to expand...


hi,
Look at this attached image, it will give you some idea's on how to solve the problem.

If you dont follow please ask.
 

Attachments

  • esp01 Aug. 14.gif
    13.1 KB · Views: 175
Last edited:
each of those 20 LED's should be divided into 7 'lots' and put in series [hopefully] meaning they really act as one LED.

7 segment is called that as there are 7 different horizontal and vertical lines that can be switched on or off to represent the numbers 0-9, 8 just uses all of them

Sometimes you see these multiplexed, so every 7 segment will have the same input, but a different ground.

We cant tell without a datasheet tho

and as Eric noted, it will have to be 12-hour clock
 
ahmedragia21 said:
thanks , but can be divided into any slots i want ? like grouping the 4 LEDs and say they are A ..etc ?
Click to expand...

hi,
Assume you have 4 LED's for each segment, wire the 4 LED's in series, make 7 segments like this for each digit.

With 7 segments you can display numbers 0 thru 9.

Once you have made one digit, make 3 more digits the same way.

Do you follow.
 
Thanks for the reply , but why you made the division like this , i mean how did you know it will work for standard ics like 74LS47
 
ahmedragia21 said:
Thanks for the reply , but why you made the division like this , i mean how did you know it will work for standard ics like 74LS47
Click to expand...

hi,
The common numeric LED's are arranged in this way, 7 segments.
Look at the front of a standard number LED and you see this pattern.

The 7447 is designed to drive 7seg LED's with segs with this pattern.

The 7447 is an active LOW, open collector, upto 15V LED driver.
 
Status
Not open for further replies.

Similar threads

  • Question
Driving Transformer Help
Replies
14
Views
924
Athosworld
  • Question
Accurate 5-digit digital ammeter module
Replies
6
Views
669
electronium
F
Digital Caliper – A Curious Thing
Replies
2
Views
1K
For The Popcorn
F
  • Question
Is it possible to make a gate level digital wrist watch
2 3
Replies
56
Views
5K
Fluffyboii
  • Question
High frequency voltage measurement with digital multimeter
Replies
15
Views
3K
electronium
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…