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One Wire DS18B20 Issue

PostPosted: Mon Oct 26, 2015 1:41 am
by Mario Medina
Hello.

I'm trying to read the temperature of a DS18B20. Initially realized that with the newest firmware (0.9.6), I obtained successfully the address from the device, but any reading will return 255. So I saw somewhere that it was a firmware issue, and firmware 0.9.5 works well. So I loaded version nodemcu_float_0.9.5_20150318 and it doesn't return any more the 255 but I always get back the same value:

Device is a DS18S20 family device
P=1
80 5 75 70 127 255 12 16 28
CRC=28
Temperature= 85.0 Centigrade

This value of course is wrong. I'm at 28°C.
As I mentioned, I can read device information but not the sensor readings.

Does anybody have any recommendations?

Re: One Wire DS18B20 Issue

PostPosted: Tue Oct 27, 2015 7:37 am
by IAN WILLIAMS
I had same problem, there appears to be an error in the firmware, I went back to an older version ..._20150318 and it work fine, I had spend hours believing I must have made an error, I tried many more recent versions and custom builds but none would work, I could read the sensor addresses but not the data just as you described. as soon as I flashed with the old image my sensors worked as expected...