Computer temperature logging

By FAR the best and one of the lowest cost ways to do this is with the
Thermochron iButtons from Dallis/Maxim.
They are fully self contained temp data loggers the size of a few
10cent pieces stacked. Programmable via the serial port.

http://www.maxim-ic.com/products/ibutton/ibuttons/thermochron.cfm

You can stick them onto surfaces, dangle them on string for mid air
measurements, submerge them underwater, and generally beat the crap out
of them and they still keep ticking.
I use them for heaps of stuff - I hang them off my harness (sometimes
off my shoelaces) to measure canyon water and air temperatures, stick
them all over the house for thermal profiling, and just recently used
them to thermally profile a passive solar heater design.
They are also fun to use for getting 3D thermal profile maps inside
instruments and racks etc.

Farnell have the kit for about $60 which includes the download cable
and a sample iButton.

Sample rate is programmble in 1 minutes intervals, and they also have
histogramming and alarms. Data can be exported into Excel and other
packages for analysis.

Only disadvantage is they aren't suitable for really high temperatures,
125C max.

Dave :)

Check out the QM-1538 digital multimeter from Jaycar. It costs $60.00
and comes with a temperature probe. It has an RS232 port to connect
with your PC and the included software will log or graph the
measurements.

Slightly O/T in the context of the O/P's requirement, but have you ever noticed
how rarely the basic accuracy of DMM's at the Jaycar/Altronics/DSE places is
ever disclosed in their advertising?  And it is even rarer for the RS232-capable
units.

Why isn't the QM-1538 exactly a "temperature probe/system that can be
attached to a PC for temperature logging"? While it is not clear from
the post whether it is the PC that is being measured and/or being used
for logging I don't see why the QM-1538 may not be suitable in any
case.

Yes. If you are implying that the QM-1538 is not very accurate you are
right. It's 0.75% +-3 from -50 to 200 degrees and 1.5% from 200 to 750
degrees.

RS232-capable


Maybe we're heading in different directions.  The cited DMM may well be
eminently suitable for the O/P's application, not knowing the accuracy he
requires.

My comment related to the lack of accuracy specs on DMM's in general from that
market sector, and on their 232-capable ones in particular.  Not thermocouple
accuracy on them, their basic (ie DCV) accuracy.  No more, no less.