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Miscellaneous => The Lounge => Topic started by: Jack2000 on 23 May 2006, 19:17

Title: Is it safe to make your own leds
Post by: Jack2000 on 23 May 2006, 19:17

I think about makeing my own leds for the key board
you know tha thing with the caps/num/scrool lock leds
i think of useing one of those leds that is like digital with lots of dots
and it will be able to show what ever i want it to
and then i will cut out the normal leds and adjust mine into it
...
so how much is the key board dependent on them ?

Title: Re: Is it safe to make your own leds
Post by: Refalm on 23 May 2006, 20:54

This is a very strange coinsedence, as someone in my neighbourhood actually did this!

He used this website and spend a total of € 0,70 on it:
http://www.metku.net/index.html?path=mods/keylights/index_eng

Title: Re: Is it safe to make your own leds
Post by: Lead Head on 23 May 2006, 22:57

Just remeber this, USB ports provide a max of 500ma of power, or 2.5Watts total.  Not sure about PS/2 ports though...

Title: Re: Is it safe to make your own leds
Post by: Aloone_Jonez on 23 May 2006, 23:45

Using one resistor for two chans of LEDs isn't very reliable, you really should use one resistor for each chain as their forward voltage drop can vary slightly - I'll post a diagram if you're unsure.

Title: Re: Is it safe to make your own leds
Post by: Jack2000 on 24 May 2006, 00:06

i think i am quite shure :)
and i can always ask my dad :)

Title: Re: Is it safe to make your own leds
Post by: mobrien_12 on 24 May 2006, 02:25

Wow, Refalm, that totally rules!  Useful for typing or playing games in the dark, and stylish.  

Jack, was that what you wanted?

The resistor thing is quite important.... take the voltage listed for the LED (say 1.5V).  Subtract it from your power supply (say 5 V for this example, leaving 3.5 v).  Now look at the current listed for the LED, say, 5 mA.

Divide the remaining voltage by the current and you get the resistor size you need, for this example 3.5 V/5 mA = 3.5V/0.005A =700 OHM  I go to radio shack and have a choice between a 750 ohm and a 650 ohm resistor, I go with the 750 for more protection for the LED.

Title: Re: Is it safe to make your own leds
Post by: Aloone_Jonez on 24 May 2006, 12:04

What I was getting at is the way the resistors are connected in the diagram is wrong, here is the right way of doing it.

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