Casio EV-680 led mod

HK-47 · Post by **HK-47** » Tue Feb 08, 2005 7:53 pm

What are the leds rated at? Ive seen leds that need 6v to run properly, maybe you accaadentaly bought the wrong led?

goodie · Post by **goodie** » Tue Feb 08, 2005 7:57 pm

They are rated at 3.7 volts.

HK-47 · Post by **HK-47** » Tue Feb 08, 2005 8:04 pm

1 make sure you run the leds in parallel
2 how are the resistors wired? parallel or series

goodie · Post by **goodie** » Tue Feb 08, 2005 8:25 pm

I always forget which is called parallel and which is series, but I have it connected like this:

except I have them connected directly to the batteries, instead of the 5v from the TV.

Post by **gannon** » Tue Feb 08, 2005 8:31 pm

That looks ok, maybe only use 1 10 Ohm resistor though to brighten it up.

HK-47 · Post by **HK-47** » Tue Feb 08, 2005 8:34 pm

Well one thing you can try is wiring the resistors in parallel, this should help a bit...
So now it looks like this:

-----/\/\/\/\/\----/\/\/\/\/\----

Make it look like this:

      _/\/\/\/\/\_
-----|            |-----
     |_/\/\/\/\/\_|

/\/\/\/\ being the resistors of course...
Edit: Gannons method works too.... Stupid post lag...

goodie · Post by **goodie** » Tue Feb 08, 2005 8:57 pm

That makes sense. I'll have to try that tommorrow.

HK-47 · Post by **HK-47** » Wed Feb 09, 2005 2:44 pm

Oh, also my way lowers the resistance to 5 ohm, when gannons lowers it to 10. So try my way if you want a brighter screen.

goodie · Post by **goodie** » Wed Feb 09, 2005 4:46 pm

Ok, I tried it both ways. Gannon's way made it only slightly brighter, and HK-47's way actually made it darker.

Could it be that 2 3mm LEDs are simply not sufficient to light a 3 inch screen? If not, what kind of LEDs should I use?

Post by **gannon** » Wed Feb 09, 2005 4:53 pm

They should be bright enough. Have you tried no resistor at all?

HK-47 · Post by **HK-47** » Wed Feb 09, 2005 4:56 pm

1 yeah, no resistor should help
2 dosnt wiring resistors in paralell half the resistance?

goodie · Post by **goodie** » Wed Feb 09, 2005 5:13 pm

Just tried it without any resistor, and strangely, it looks about the same. I also tried upping the voltage to 6, but nothing changed.

Post by **gannon** » Wed Feb 09, 2005 5:15 pm

Then I'd say that your leds must be in a crappy position, or be very crappy leds

Guest26 · Post by **Guest26** » Wed Feb 09, 2005 5:23 pm

2 dosnt wiring resistors in paralell half the resistance?

No the resistance stays the same thorugh out a parrell circuit but the current is halfed though in a parrell circuit.

goodie · Post by **goodie** » Wed Feb 09, 2005 5:32 pm

gannon wrote:Then I'd say that your leds must be in a crappy position, or be very crappy leds

I used these LEDs. As for their position, I shoved them in the slot the bulb used to be in. I guess I should try to find brighter ones, eh?