The Hdd Pin 11 Mystery Solved, using the correct method...multi meter Options

[jamesnmandy]

So i directly soldered a wire to the notorious "pin 11" in the HDD connector, you know, the fifth from the end, the one that people are using for the HDD Activity mod, but nobody here seems to be able to give a straight answer on as far as if it is ground when idle or ground when active, or how much voltage is actually there.....I have seen this asked so many times in the forums with so many guesses and so many ????'s

It's confirmed now. Using my Fluke True RMS 175 Multi-Meter it measures 2.66v when idle (pretty much all the time) and 0.0v when the HDD is active (only when you actually access something on the HDD).

Unfortunately this doesn't quite answer my questions I have about using the activity source in conjunction with the standard HDD Window with LED mod......I want my LED's in the HDD window to blink OFF when the HDD is accessed but remain lit otherwise.

I have seen RJBTech's post in the HDD Activity Mod thread saying to go +5v---1k Ohm Resistor----anode from LED and pin 11 connection together here------cathode from LED to standard GROUND (0v)

His theory being that when the HDD activates, it goes to 0v, essential becoming a momentary ground, providing the path of least resistance, giving the +5v somewhere to go before getting to the LED...and then otherwise when the HDD is not active, the presence of 2.66v would force the power through the diode(LED) towards the common ground(0v).

Makes sense, except here's the thing. I want to use 4 LED's in my window. Actually I already have them installed, window made, LED's pre-wired, and now pin 11 connection made, but I am having a problem understanding the 1k Ohm Resistor RBJTech mentioned. According to all of the LED calculators, for two LED's in parallel (3.5v because mine are blue and white), i need one 47 Ohm resistor, for all four LED's i need one 22 Ohm resistor....ok, sounds right.

But there's a big difference between 1k Ohm and 22k or 47k Ohm.

So what do you guys think? I need help determining which resistor would be correct, and if it is safe to wire it up the way RJBTech mentioned. So far his method sounds the safest.