Impmon wrote:
> I wanted to change the indicator LED a bit. First off, the HD
> indicator LED is uselessly dim because of a cheap optic guide so I'm
> going to discontinue that LED and I wanted to use the light bars
> instead. The light bar is lit by 4 LEDs total. I checked, the hard
> drive header's + side is tied to +V source, and the - side floats high
> for no activity and goes low for activity.
>
> How do I make it so the light bar is ON when there's no activity and
> goes off when there's activity? Obviously transistor is needed since I
> doubt the PC motherboard is designed to handle 4 LEDs at once.
+12--- -------------+
e\ /c |
--- |
| [LightBar]
[1K] |
| [R]
IN --+ |
|
Gnd ------------------+
IN goes to wherever you have the low for activity and
high for no activity. The PNP can be whatever you have
on hand - compute R to keep current through the Light bar
LEDs to 20 mA or less.
Ed
>
> I am getting blue/yellow bi-color LED to replace the stock LED for
> another reason: the standby mode is also tied to +V source and - pin
> goes low when PC is in standby mode. So it'll be blue steady, fla****ng
> blue with HD activity, and yellow when standby. The yellow side will
> also need driver transistor to control 4 LEDs but should be much
> simplier as it's on when mobo's header goes low. PNP should do the
> trick, collector on the LED cathode side, resistor from base to mobo
> standby LED header, and emitter to ground (unless I'm wrong?)
|
