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.

[jamesnmandy]

i forgot to mention, RJBTech's suggestion i believe was also using one LED, and i think a red one rated a bit lower than the white/blue leds i am using. I want to know how to do this with four white/blue LED's wired parallel.

[jamesnmandy]

got it working....thanks anyways

CODE

+5v(yellow wire)---33 Ohm resistor---anode(long leg) of LEDs---diode(LED)---cathode(short leg) of LEDs---0v(black wire)
                                                 |
                                                 |__connection to pin 11

this gets you 3.05v after the resistor, a little too high for red leds, a little underpowered for white/blue leds but i would not want them any brighter than they are now and running them at 3.05v is nearly a whole volt under max so LED life should be good

FYI, a 20 ohm resistor would have worked to get 3.5v to the leds roughly if anyone tries it and wants to push the (white or blue) leds near max

and also, something i learned, 20 ohms means 20 ohms, not a 20k resistor, thats 20 thousand ohms, big difference, so a 47 is not the same as a 47k or 4.7k



This post has been edited by jamesnmandy: Dec 9 2008, 07:16 AM

[jamesnmandy]

also meant to add, my HDD is a 20Gb Samsung

[darthdrummer]

It is really easier to look at the resistor in terms of the amount of current that it will supply rather than the voltage (current limiting resistor).

For instance 5V source / 1K (1000ohm) resistor allows a maximum of 5mA of current to flow from the source through the LED to the ground.

All data sheets will make mention of how much current the LED is rated at and the typical amount required.

[jamesnmandy]

It is really easier to look at the resistor in terms of the amount of current that it will supply rather than the voltage (current limiting resistor).

For instance 5V source / 1K (1000ohm) resistor allows a maximum of 5mA of current to flow from the source through the LED to the ground.

All data sheets will make mention of how much current the LED is rated at and the typical amount required.

interesting method....but these leds handle up to 20mA of current at up to 4.0v each, so i was needing as close to 80mA as possible at 3.0+ volts....

i dont know how to do the math on what i have using the 33 ohm resistor, but i was wanting a 20 ohm resistor which i could not find, the 33 ohm resistor is keeping right at 3.05v to the resistors, i have no clue what mA rating, never could get the multi meter to read mA....maybe below range for it, dunno, all i know is it worked great

[jamesnmandy]

results

http://www.youtube.com/watch?v=L2on_gXziJk

[xTKxhom3r]

wow thats awesome bro you make me want to get off my ass and cut a window on my hdd case....

[xTKxhom3r]

hey bro i want to do this tonight so i wanted to ask you if you can post some more pics of how you wired the led's and cut the window please!

[xTKxhom3r]

ok i got it all working except the blinking of the led's i connected

i have 6 led's 3 on each side

all the long legs connected together to a 22ohm resistor then to the yellow wire (3 leds per resistor)

then all 6 short legs to the black wire

then i connected pin 11 to the black wire but the leds didnt blink they just stayed lit

if i disconnect them from the black wire and just directly to pin 11 they stay off and turn on on activity

so what am i doing wrong...

[Exige_]

Yeah that diagram doesn't make sense to me

[jamesnmandy]

Yeah that diagram doesn't make sense to me

it's like this guys

yellow wire --> resistor/s --> here you connect all of the LED positive (long legs) connections and also add the wire you ran to pin 11 --> negative (short leg) of LED's wired together to connect to black wire

xTKxhom3r you have it all right, but instead of connecting the wire which goes to pin 11 to the negative side of the LED's, connect it to the positive side of the led's, after the resistor....on the LED side of the resistors....

so the power flows from yellow, into resistor, and then when HDD is active and pin 11 goes to 0v the power flows to ground, it never gets to the LED's, which is why they go out, then when the HDD is not active there is 2.66-2.7v on pin 11, which means the power will naturally flow towards the closest ground, which is on the other side of the LEDs, the black wire....which is why they stay lit when the HDD is inactive

This post has been edited by jamesnmandy: Dec 12 2008, 01:49 AM

[jamesnmandy]

maybe this will help?



This post has been edited by jamesnmandy: Dec 12 2008, 02:36 AM

[xTKxhom3r]

oh wow thats exactly what i needed haha btw your handwriting reminds me of mine lol! thanks allot bro!!

[jamesnmandy]

no prob, yeah, the way you had it would work, but the LED's would only light up when the HDD went active......wait until you see the LED's do a dance when installing a game to the HDD....LOL, they go nuts!