[off topic-ish] ide access led?

[phreak97]

i have three 80gb ide hard drives in my pc, and i know its possible to put access leds on the two secondary drives, because i have seen hard drive racks with built in access leds. i was looking at pinouts and from one it looked like pin 39 was the one i was looking for, but i dont want to try anything untill i have confirmation of that.. my hard drives are too valuable for that, especially seeing they are all mostly full.

[gannon]

Try it out on an old 5 gig drive or something then

[Adeptus]

Try searching http://forums.bit-tech.net/ - it's a good PC modding forum. I'm 99% sure I've seen info on this there.

[bcforn64]

i have three 80gb ide hard drives in my pc, and i know its possible to put access leds on the two secondary drives, because i have seen hard drive racks with built in access leds. i was looking at pinouts and from one it looked like pin 39 was the one i was looking for, but i dont want to try anything untill i have confirmation of that.. my hard drives are too valuable for that, especially seeing they are all mostly full.

You are correct. Pin 39 is the pin you want to tap for status indication. When the HD goes active an active low signal is sent through the line. Simply hook the negative pole of an LED to this pin and the positive pin of the LED (with appropriate resistors!) to a positive source.

Only problem with this is if you have two hard drives running off one IDE cable the LED should light if access is going on on either drive.  I believe the active low signal is a signal comming from the hard drive, so it may be possible to cut the cable into parts and tap into pin 39 from each of the respectable drives. If this is even safe for the hardware. I'd wait for a second opinion before doing that.

[phreak97]

i have some old 386's and 486's with really crap hdd's (less than 1gb each) i might experiment with these a bit first.. but still..
/me awaits second opinion

[Aidan]

Take a look at a mirror of HWB for the pinout for IDE: http://www.gamesx.com/hwb/co_IdeInternal.html

That should tell you where the LED driver is. Due to the design of the IDE interface, it's likely to be an open collector output.  

[phreak97]

lol im stupid.. i was googling for pinouts.. i never even thought about the gamesx hardwarebook:P
thanks.

[dum dum]

the hardwarebook had been avaliable at www.hardwarebook.net for several years now,  a bit more recent than gamesx's mirror, but seems to have frozen at 2001 - some 2004 news gives a bit of hope though