Circuit to turn fan on when HD is on or reaches a certain temp??

[BehindEnemyLines]

Is there a simple circuit that can turn on a fan when there's power to the hard drive spindle motor? I notice all? of them have four leads into them. If that's not possible, how about temperature based instead. Say at 40 degrees Celcius, the fan turns on, and turns off when it's below that threshold.

The reason is that I've a DVD player that is hacked. It can play MP3, MPEG1, MPEG2, and JPEG from the hard drive. The HD uses the DVD player PSU (since it has a +12V and +5V). When the DVD player is in standby mode, the HD turns off too. I would like a circuit that, when the HD turns on, the fan also turn on to prevent the HD from overheating (which it did when the fan stopped).

 

[AbsolutDealage]

This is not highly technical.

Fan Controller

 

[imported_Nail]

Thermistor, varistor, zener diode, and lots of tape (or a "soldering iron" if you're a fancy boy).

 

[Calin]

You could just take the signal from the "HDD" diode, command a transistor with it, and with the transistor command a fan. If you would like some "memory" then you could use another stage with a capacitor loaded from the first transistor and commanding a second stage transistor powering the fan.
I still dream at the diabolic machines in Tom and Jerry movies

Calin

 

[BehindEnemyLines]

Originally posted by: Calin
You could just take the signal from the "HDD" diode, command a transistor with it, and with the transistor command a fan. If you would like some "memory" then you could use another stage with a capacitor loaded from the first transistor and commanding a second stage transistor powering the fan.
I still dream at the diabolic machines in Tom and Jerry movies

Calin

I remember that on the IDE cable, there's a wire that's used to control the LED (that flashes when the HD is accessed). Saw it somewhere, but don't remember which ones. I forgot to say that I'm not an engineer, so schematics is the only way I can (barely) build it.

 

[blahblah99]

Just go buy one for $20 and save yourself the time and hassle.

 

[BehindEnemyLines]

Actually, I would buy one of those device if I know what it's called and where? By any chance anyone knows where I can get one? Remember that the device must turn OFF (rather than slowing it down) the fan when the temperature is below a threshold and ON when it's above.

Thanks.