How do I turn these temp VU's into Sound VU's

gamephile

Member
Jul 10, 2001
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Hello all,

I have this Logisys front panel that I received as a gift:

http://www.logisyscomputer.com/viewsku.asp?SKUID=FP800SL&DID=FRONTPANEL

Among it's humorous features, the remote start for instance, it provides two VU's that are hooked to basic thermistors that they expect you to tape down to the cpu cooler or the case. These thermistors are inaccurate (+10/15C) and slow to update so I'm interested it repurposing the VU's to be sound meters while playing music in Winamp.

The connection in the back of the Logisys panel is two pins per VU. This, coupled with the fact that the sensors look like little metal sperm (for lack of a better term), leads me to believe they are thermistors and can be replaced by any other type of resistor.

I realize this would necessitate some circuitry which I'm comfortable to build and test but I'll need some help designing. Ideas and input anyone?
 

Qacer

Platinum Member
Apr 5, 2001
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Interesting. The sensors that you are talking about sound more like thremocouples. They look like little metal sperm and its two terminals exhibit a change in voltage potential when the temperature changes. If that is the case, the simplest way I can think of making this work with Winamp is to use PC stereo jack (the same connector as the speaker input plug) and tap off from the left and right sections of the stereo jack to detect voltage changes. Just remember to use the ground section of the stereo jack as the reference for these stereo voltages.

However, you would first need to determine the voltage levels at the thermocouple terminals to get an idea on what kind of voltage levels you are dealing with. Just cut off these little metal sperm wires and use a multimeter to probe its terminals while putting them on top of the CPU cooler.
 

gamephile

Member
Jul 10, 2001
162
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Wow a reply! Thanks for your help. I'm going to be working on this in the next couple of days and I'll come back with some updates. What voltages should I be expecting to come off the speaker output? Thanks for your help.
 

Qacer

Platinum Member
Apr 5, 2001
2,721
1
91
From my experience, the speaker output normally peak at .700V or so. For thermocouples, you normally have to find out what type you are using since they have different offset voltage values.