In article ,
"AZ Woody" writes:
Sounds to me that 1-wire might be the way to go. A two wire buss could
support the sensors, and a $20 adapter for the computer. (use a full cat 5
for distance, and to provide for expandability.)

They're cheap, and if the location will be inaccessible, I would
put in two of them, each on a different pair, so that if one dies,
you can switch to the other.

Dallas provides some good sample code on their website for interfacing
Doing a "parasite" read on a sensor can be done on a single sensor in about
a second, Each sensor has a unique ID, and the bast part is, I've gotten
them for $3 each in to-92 cases. So, if you got 15 sensors, you can read
them about 4 times a minute if you want. They're good to +/- 1 degree c or
+/- 2 degree C based on the specific sensor

The DS1820's are accurate to fractions of a ºC, although it's
complicated to read them any more accurately than 0.5ºC (and
might not be possible in parasitic power mode -- not sure on that
point).

You can build sw on windows and Linux for sure (those are the only two I've
done)

I'm currently monitoring temps in my HVAC system, outside temps, and even
have one mounted in a "can cooler" near my computer that will alert me if my
beverage gets too warm.

Here's a section of logging from my system (running on Solaris x86)...
Oct 27 16:13:48 Temperature - Outdoors 18.0
Oct 27 16:14:37 Temperature - Freezer -23.0
Oct 27 16:14:37 Temperature - Fridge 4.5
Oct 27 16:15:48 Temperature - Freezer -23.5
Oct 27 16:16:21 Temperature - Loft 24.5
Oct 27 16:17:05 Temperature - Freezer -24.0
Oct 27 16:18:32 Temperature - Freezer -24.5
Oct 27 16:20:05 Temperature - Fridge 4.0
Oct 27 16:20:21 Temperature - Freezer -25.0
Oct 27 16:22:22 Temperature - Freezer -25.5
Oct 27 16:27:05 Temperature - Freezer -25.0
Oct 27 16:27:55 Temperature - Fridge 3.5
Oct 27 16:28:55 Temperature - Freezer -24.5
Oct 27 16:30:49 Temperature - Freezer -24.0
Oct 27 16:32:49 Temperature - Freezer -23.5
Oct 27 16:35:17 Temperature - Freezer -23.0
Oct 27 16:37:47 Temperature - Freezer -22.5
Oct 27 16:38:19 Temperature - Fridge 3.0
Oct 27 16:38:44 Temperature - Loft 24.0
Oct 27 16:41:01 Temperature - Freezer -22.0

--
Andrew Gabriel