Hi Bill,
Here's a gotca, If you are running your 1 Wire lines any distance more than a
few feet put some sort of surge surge suppression network on your line.
It's best to have one at both ends, a small series resistor (100 ohms) and
some sort of clamping device to ground. Dallas makes a small 6 pin ic
specifically for this purpose, available with or without an internal series
resistor. I cant remember the number but you should be able to find it
on their website. I learned this the hard way, 1 nearby lightining strike
and both the DS 1820 and the microcontroller were fried.

Bruce