Dual LED MB setup

[salutka]

Hi,

I have been searching for over a year now on how to get a dual color led to work with my motherboard. Ok, the motherboard has a constant negative and uses the positive pins to turn the power and HDD leds on/off. Now, the dual color led has a common positive and uses 2 negatives to operate both colors. I was thinking of a PNP transistor but at this point any suggestion would be really appreciated.

Thanks in advance.

 

[Diver300]

You would want an NPN transistor to drive each LED, as you are sinking current not sourcing it.

Or you could use an inverter such as a 74HC04.

Either way you need a 5 V source and current limiting resistors to feed the LED

 

[salutka]

Thanks for the reply, I made a diagram of my setup, (yeah, I used paint brush lol) and I think I want to try the NPN transistor, now i'm very visual so if you can modify my diagram I would really appreciate it. Thanks

 

[Diver300]

This is the circuit you need for each LED.

R1 should be about 330 Ω and it is needed to limit the LED current
R2 and R3 should be 10 kΩ

The transistor can be just about anything NPN

https://en.wikipedia.org/wiki/Transistor says how it all works.

 

[salutka]

Thanks a million, can't wait to try it out.

 

[DMW]

you might be intrested, i tapped off my HDD light and using a PIC made it into a % meter with bar graph

vid1:
**broken link removed**

vid2:
**broken link removed**

pic1:
https://i12.photobucket.com/albums/a239/muzzwezz/IMGP0049.jpg
pic2:
https://i12.photobucket.com/albums/a239/muzzwezz/IMGP0047.jpg

 

[salutka]

That looks really sweet DMW, definitely a cool case mod. But I only have room for one single LED in my project. But I would love to make one some day.