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Dual Time Digital Alarm Clock

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Dual Time Digital Alarm Clock

Postby pasanlaksiri » Thu Mar 08, 2007 7:30 am

I made dual time digital clock. Its working properly. But Now wanna connect big display for it. What is the best way to do it.

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pasan......
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Postby vu3cns » Thu Mar 08, 2007 8:18 pm

Hi,
For large displays you need to use additional transistors for switching display segments. Here you can find the datasheets of large LED displays. Note that PIC can source / sink only 20mA on each o/p pins. Use darligton transistors for switching common anode/cathode of displays.
:D :D
VU3CNS

P.S: I have plan to re-write the circuit/program for Large displays
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Postby pasanlaksiri » Thu Mar 08, 2007 9:14 pm

vu3cns wrote:Hi,
For large displays you need to use additional transistors for switching display segments. Here you can find the datasheets of large LED displays. Note that PIC can source / sink only 20mA on each o/p pins. Use darligton transistors for switching common anode/cathode of displays.
:D :D
VU3CNS

P.S: I have plan to re-write the circuit/program for Large displays


Hey this Clock has Fading effect or some thing like that. I dont know how to explain it.

I test using these IC's ULN 2003 with BD562, two 74HC541 and two CD4050. But ..........
pasan......
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Postby vu3cns » Thu Mar 08, 2007 10:36 pm

Adding BC548 in common anode (as common collector configuration) may slove this problem, this will increase the current for more brightness
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Postby pasanlaksiri » Thu Mar 08, 2007 11:17 pm

vu3cns wrote:Adding BC548 in common anode (as common collector configuration) may slove this problem, this will increase the current for more brightness

ok i'll try. Thanks for the help
pasan......
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Postby arupch » Tue Jul 31, 2007 8:40 am

hi,
i've also built the clock successfully. but does anybody have a pcb layout?

thanks
_________
Arup
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Postby vu3cns » Wed Aug 01, 2007 9:16 pm

Hi,
I designed a circuit for Big displays, but I need someone help to make a PCB, if anybody interested please post here.
73's
VU3CNS
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Postby michael » Tue Aug 07, 2007 12:45 am

I have a clock design in progress right now. It uses a basic stamp, DS1302 Timekeeping Chip, MAX6954 by Maxium IC and 8 Kingbright PSC23-11GWA 16 segment displays. I found the displays on e-bay (Here:http://cgi.ebay.com/KINGBRIGHT-LARGE-2-3-TALL-16-SEGMENT-GREEN-LED-DISPLAY_W0QQitemZ230157775758QQcmdZViewItem?hash=item230157775758)

The ds1302 will make this design very accurate at keeping time.
It will have these features: Time, day, month, year, temperature, and Alarm 1 and 2. If there is enuf program space left i will incorporate a eeprom chip so I can display custom messages.

I pretty much have the all circuit wired on Porto board. and as of right now I'm working on the programming.

I'll keep ya posted as my design progresses.
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Postby vu3cns » Tue Aug 07, 2007 4:35 pm

michael wrote:The ds1302 will make this design very accurate at keeping time.
It will have these features: Time, day, month, year, temperature, and Alarm 1 and 2. If there is enuf program space left i will incorporate a eeprom chip so I can display custom messages.

I pretty much have the all circuit wired on Porto board. and as of right now I'm working on the programming.

I'll keep ya posted as my design progresses.


All the above features are in this design also, with a single chip, see

http://www.hamradioindia.org/circuits/clock.php

The PIC's built in Timer has a very good accuracy, so there is no need of an external chip. I designed it for big displays but I haven't enough time to make PCB artwork, if anybody helps, I will re-write the program.
Regards,
VU3CNS
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Postby michael » Tue Aug 07, 2007 5:42 pm

The PIC's built in Timer has a very good accuracy, so there is no need of an external chip. I designed it for big displays but I haven't enough time to make PCB artwork, if anybody helps, I will re-write the program.
Regards,
VU3CNS


Ya, I wasn't knocking the PIC or your project. I just thought that i would share mine seams they are very similar in function. because I am just now learning the PIC world. writing code for them is a daunting task. On the other hand I know the pBasic language well. I had a few BS interpreter chips laying around and thought i would put them to good use.

As far as your art work I Could help. Would you like the displays and control circuits on separate boards or on the same board? also do you have a data sheet for your displays?
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Postby vu3cns » Thu Aug 09, 2007 4:31 pm

michael wrote:As far as your art work I Could help. Would you like the displays and control circuits on separate boards or on the same board? also do you have a data sheet for your displays?

First, thanks for your offer :D . I like to use two boards, becuse if one may like to use another size display, then it may helps.
I have the data sheet in my PC, but now I am not at home, I will back with in two days.
Also I will upload the circuit in a few days
:D
VU3CNS
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Postby vu3cns » Mon Aug 13, 2007 10:40 am

Hi,
I here by sending you my clock circuit for 1.2 inch displays, but this can also use for 2.3 inch displays (datasheet available at http://www.taiwanoasis.com.tw) because that much current can be given by this circuit. Please note that the values of resistors are not calculated, rough figures are given.
Please download the circuit and datasheets of displays from THIS LINK
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Postby michael » Tue Aug 14, 2007 8:52 am

vu3cns wrote:First, thanks for your offer :D . I like to use two boards, becuse if one may like to use another size display, then it may helps.
I have the data sheet in my PC, but now I am not at home, I will back with in two days.
Also I will upload the circuit in a few days
:D
VU3CNS


I was just woundering what you thought of this for the display layout?
Image
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Postby vu3cns » Tue Aug 14, 2007 10:30 am

michael wrote:I was just woundering what you thought of this for the display layout?


It is a very nice layout, proceed. I forgot to say one thing, you have absolute freedom to select PIC to display connections to make the artwork more easy.
Thanking You,
VU3CNS
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Postby michael » Tue Aug 14, 2007 6:08 pm

vu3cns wrote:
you have absolute freedom to select PIC to display connections to make the artwork more easy.
Thanking You,
VU3CNS


Thanks, That will definitely make things easier. I will let ya know what the final configuration is.

Michael
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