Did some tests
All located within inches of each other in the same room.
What I think is true
19.5 DS18B20 on electricity meter sensor in dining room (always believed this to be right)
19.5 DS18B20 on my boiler monitor (brought into dining room, placed next to elec mon sensor), so they agree
18.5 weather station in dining room (my assumed reference, although on hard surface and it's very very slow to react)
14.8 DS18B20 outside (believed to be similar to the car - VW passat)
14.6 weather station on a plant pot about 1 ft from this after 30 mins
So that makes me think the weather station is there or there abouts
this is what the two read
22.7 output powered DS18B20 #1
23.9 output powered DS18B20 #2
picaxe supply from reg 3.301v (verified within .1v across 3 different meters)
picaxe ouput 3.30v
voltage across 4K7 3.294v
looked at the connections again, just to see if I'd done something daft, nope, looks fine. Dropping another 4K7 across to make essentially 2K35 made no difference
code on all picaxes
readtemp12 3,w3
b3 = w3 / 256 / 128
if b3 = 1 then
w3 = w3 ^ $ffff + 1
b10="-"
else
b10="+"
endif
w3 = w3 * 10 / 16
b12 = w3 / 10
b13 = w3 // 10
if b12 < 10 then
b11="0"
serout XBEEdataoutPIN,BAUD,("aR",s1,s2,"T",b10,"0",#b12,".",#b13,"--")
else
serout XBEEdataoutPIN,BAUD,("aR",s1,s2,"T",b10,#b12,".",#b13,"--")
endif
going to try a DS on a wire, it can only be duff sensors or local heating now
________
volcano vaporizer reviews