7 Segment Led Board.

[b_sandoval]

Hello Everyone,

I'm loocking for some information about how to make a 7 Segments Led Board using regular led's, I pretending to drive each line with 10 5mm Led's
something like this:

... O O O O
O .............. O
... O O O O
Just don't pay attention on the dot's, I coudn't make my grafic better.
Please if somebody have some ideas, please let me know, I'm rushing with this project and my time is to short.

Thanks.
[/b]

[Sebi]

Assume You need some big display. First determine how many LED need for one segment, and what is the supply voltage.

[b_sandoval]

Thanks for the quick answer, that was very fast.

I try to post a better graffic, but for some reazon I cound't.

My idea is to drive each segment with ten led's with 5v power supply.

Thanks for your HELP.

[Nigel Goodwin]

Originally Posted by b_sandoval

My idea is to drive each segment with ten led's with 5v power supply.

With a five volt power supply the best you can do is two LED's in series, with a common series resistor. So for ten LED's per segment you will need the ten LED's and five resistors.

[b_sandoval]

hi,
I have some fet's RFD16N05L (16A, 50V, 0.047 Ohm, Logic Level,
N-Channel Power MOSFETs) that i can use, so may be one for each segment or 10 led's. How do this sound?
Thanks.

[Kingpin094]

http://www.mohr.se/Electronics/Bigclock/Bigclock.htm

I built one like the site above but I used 6 leds per segment from a 12V supply. Works like a champ.

[b_sandoval]

Hello,

Man, your project is good, I was thinking in something similar, I have some graffic, I jus don't know how to post to you see, but your project is goooood !!

Thanks

:P

[Dean Huster]

When driving that many LEDs per segment, you're really better off building a higher voltage supply just for the display, say 25 to 30v in your case. The current requirements will be a lot less, switching transistor selection is easier and there are some IC LED drivers that can still handle 30 volts so you may be able to keep the parts count down. In addition, you can put all the LEDs in series which makes for a lot easier implementation on the board. The idea of series/parallel arrangement of LEDs just so you can use a 5v supply doesn't sound like a lot of fun to me. I'd much rather build a higher voltage supply using a 7824 if you insist on regulation -- and this application doesn't require regulation -- rather than a really beefy 5v, multiple-amp supply to do the same job.

Dean