Just FYI, got a couple of these off ebay for temperature display after I saw Jim's panel using them (or something very similar).
They only come with a one meter lead, but I've never had any trouble running single DS18B20s on 10 or 20 meter runs before, so I figured I'd just splice in some CAT5.
Well that didn't work, I couldn't even get them to work with two meters spliced in.
The bus rise time was too slow so I added a 2.2K pull-up from the 5VDC wire to the data wire, which works for extensions as much 10 meters, although I suppose it voids any warranty.
Example listing:
http://cgi.ebay.com/Digital-LED-Tem...ultDomain_0&hash=item563fdc376f#ht_4706wt_957
--ewd
They only come with a one meter lead, but I've never had any trouble running single DS18B20s on 10 or 20 meter runs before, so I figured I'd just splice in some CAT5.
Well that didn't work, I couldn't even get them to work with two meters spliced in.
The bus rise time was too slow so I added a 2.2K pull-up from the 5VDC wire to the data wire, which works for extensions as much 10 meters, although I suppose it voids any warranty.
Example listing:
http://cgi.ebay.com/Digital-LED-Tem...ultDomain_0&hash=item563fdc376f#ht_4706wt_957
--ewd