On: Tue, 13 Jan 2004 11:47:44 -0500 Nancy Haitz <[EMAIL PROTECTED]> Asked:
I have a general sort of question.Snip:
Snip:I was wondering if anyone on this list had come up with a means of=20 accurately testing the ambient temperature inside the box, in various=20 areas.
Anyone come up with a workable computer thermometer?
Nancy=
Hi Nancy;
You need to be very careful and electrically knowlegeable when inserting any metalic object into the case of a computer when the power is going to be turned on. ( I know that you know that, but the warning always needs to be given).
I am working on a three channel one. Processor/Heatsink temp, Outlet Temp and inlet temp. It could be more channels. Add hard drives or whatever.
I have the read out design done. Some years ago I was given many sticks of seven segment LED's. I have to buy some stuff from Jameco and get on with it.
The sensors will use up the National LM34AH temperature sensors sampled to me many years ago.
I might be able to use a freeware analog data display program downloaded years ago to read the sensors through the serial port and display on the monitor.
If it works, it could be changed to use a more common transister junction temperature sensor.
It is however a part time project sort of geared to my upgrade to OSX schedule, so might take a while. I have a carrier card coming, then the processor ZIF and then OS10.? ( hope to be 10.3 but who knows).
How accurate?
All temperature measurements are always innaccurate. If you could get the probe right where you want to measure, the presence of the probe would affect the measurement. With processors it is not possible to externally get to the junction. I believe the processors that allow temperature measurement might have a pin dedicated to that function. But I have not researched it. I have read some where on the web that only certain processor models allow temp measurement and not all processors in the same model of Apple computers allow it.
Probably not better than +/- 2 deg C more likely +/-4 deg C. With my scheme not better that +/- 6 deg C ( Have to guess a fudge factor based on probe location).
There is hope however,
ernie
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