Note: if you have apProblem with DS18B20 on a ESP8266
Posted: Wed Jan 24, 2018 1:35 pmDear all engineers.
I have been working on connecting a One Wire DS18B20 sensor to a ESP and Atmega328. Using the same software on the 5 Volt Atmega328 with a 4K7 pull up all worked fine but at the 3.3V ESP it didn't.
I checked this forum on problems with this DS18B20 and saw a suggestion to lower the pull up from 4K7 to 1.5K. I lowers it to 1K and saw that it suddenly worked.
Many articles are written with the suggestion that with a 4K7 pull up it works fine. It may have done this but my experience together with the articles on this forum show that if you have this problem lower the Pull up and use a well tested example sketch.
An other tip is regarding the One Wire library. I worked with and old library that did not recognize the ESP8266. Check that you have an up to date library.
https://github.com/adafruit/ESP8266-Arduino/blob/esp8266/libraries/OneWire/OneWire.h
I have been working on connecting a One Wire DS18B20 sensor to a ESP and Atmega328. Using the same software on the 5 Volt Atmega328 with a 4K7 pull up all worked fine but at the 3.3V ESP it didn't.
I checked this forum on problems with this DS18B20 and saw a suggestion to lower the pull up from 4K7 to 1.5K. I lowers it to 1K and saw that it suddenly worked.
Many articles are written with the suggestion that with a 4K7 pull up it works fine. It may have done this but my experience together with the articles on this forum show that if you have this problem lower the Pull up and use a well tested example sketch.
An other tip is regarding the One Wire library. I worked with and old library that did not recognize the ESP8266. Check that you have an up to date library.
https://github.com/adafruit/ESP8266-Arduino/blob/esp8266/libraries/OneWire/OneWire.h