dallas ds18s20 reading is wrong / discovery doesn't work anymore

francmarx commented 2 weeks ago

The problem

after update to ESPHome 2024.6.1 my ds18s20 devices are sending wrong values
discovery doesn't work anymore, got log: [W][gpio.one_wire:078]: Found no devices!
found this message in log: [E][dallas.temp.sensor:149]: unexpected COUNT_PER_C value: 84

maybe this comes from latest changes of 1-wire timing in esphome/components/gpio/one_wire/gpio_one_wire.cpp [fix(dallas): make recovery time for 1-bit equal to that of 0-bit (https://github.com/esphome/esphome/pull/6763)]

I found out, that ds18b20 devices ('B' type) works fine, but ds18s20 devices ('S' type) doesn't work correctly.

additionally I think there is an error calculating higher resolution for ds18s20, at esphome/components/dallas_temp/dallas_temp.cpp / line 150: temp = ((temp & 0xfff7) << 3) + (0x10 - this->scratch_pad_[6]) - 4; should be temp = ((temp & 0xfffe) << 3) + (0x10 - this->scratch_pad_[6]) - 4; => truncating the 0.5°C bit from temperature data (according to ds18s20 datasheet)

Which version of ESPHome has the issue?

ESPHome 2024.6.1

What type of installation are you using?

Home Assistant Add-on

Which version of Home Assistant has the issue?

2024.6.3

What platform are you using?

ESP8266

Board

nodemcuv2

Component causing the issue

ds18b20

Example YAML snippet

No response

Anything in the logs that might be useful for us?

No response

Additional information

No response

sanchosk commented 2 weeks ago

Same issue here :( After today's update of ESPhome, the DS stopped working :(

uli-rpi commented 2 weeks ago

I've changing from Dallas component to 1-Wire, and plattform: dallas to plattform: dallas_temp, after that everything works as usual again

sanchosk commented 2 weeks ago

Did not work for me - I had dallas_temp there. Before the update today, I've used platform dallas and that worked OK.

uli-rpi commented 2 weeks ago

maybe https://github.com/esphome/issues/issues/5908

francmarx commented 2 weeks ago

@uli-rpi

I've changing from Dallas component to 1-Wire, and plattform: dallas to plattform: dallas_temp, after that everything works as usual again

do you have ds18B20 or ds18S20 devices ? B works, S works not

lkrajicek commented 2 weeks ago

I have DS18B20 and after upgrade and changing to 1-Wire component it works only for about 50 minutes, then I got in logs Found no devices!

uli-rpi commented 2 weeks ago

@uli-rpi

I've changing from Dallas component to 1-Wire, and plattform: dallas to plattform: dallas_temp, after that everything works as usual again

do you have ds18B20 or ds18S20 devices ? B works, S works not

i use 3 sensors of ds18B20

ssieb commented 1 week ago

@francmarx can you find me on the esphome discord? I don't have any S20 sensors, so I had no way to test it and the calculation for those is a little odd.

ssieb commented 1 week ago

For anyone else having detection or crashing issues, try this (will be in the next point release):

external_components:
  - source:
      type: git
      url: https://github.com/esphome/esphome
      ref: dev
    components: [ gpio ]
    refresh: 1min

nickduvall921 commented 17 hours ago

Hey, I run ESP8266's with about sixteen DS18B20 sensors running in parasite mode on long ~30 to 70ft runs. I know my setup pushes the dallas sensors to the limit but it has been working good for over a year now. Before 2024.6 i could read them perfectly. But after i updated to 2024.6.6 they started reading 85 on most of the sensors. I was able to revert to just the old dallas component via this code and it immediately resolved the issue.

external_components:
  - source:
      type: git
      url: https://github.com/esphome/esphome/
      ref: 2024.5.5
    components: [ dallas ]
    refresh: 1min

dallas error

Here is a screenshot showing when i updated to 2024.6.6 and then when the lines go back to normal is when i reverted to the 2024.5.5 Dallas component.

FYI i also tried the dev channel above but it had no effect on the sensors. I think it must have something to do with pulling the data line low for too long or something and the sensors are not able to get enough power as they come back with valid checksums on the scratchpad when they read 85.

ssieb commented 14 hours ago

Parasite power has never been directly "supported". Try using the config method from https://github.com/esphome/issues/issues/5908#issuecomment-2196033203 and see if that works for now. I will try to add actual support for parasite power in the next release if I get time.

esphome / issues