Dallas sensor not found

ESPHome
1

I have been trying now for a couple of hours.

I get this error:

[21:58:45][C][dallas.sensor:073]:   Pin: GPIO13 (Mode: INPUT)
[21:58:45][C][dallas.sensor:074]:   Update Interval: 60.0s
[21:58:45][W][dallas.sensor:077]:   Found no sensors!
[21:59:07][E][dallas.sensor:126]: Requesting conversion failed
[22:00:07][E][dallas.sensor:126]: Requesting conversion failed
[22:01:07][E][dallas.sensor:126]: Requesting conversion failed

The config is:

esphome:
  name: eggklocka
  platform: ESP32
  board: esp32dev


dallas:
  - pin: 13

I have also tried GPIO13, GPIO27 and GPIO33.
The board is a TTGO T5 2.9 inch display ESP32.
I have tried in both normal mode and parasit mode. With and without the pullup resistor (read some posts that it could work).
Tried two different Dallas sensors.

Current wiring (this is temporary, just to get proof of concept):

IMG_20210408_220803303
IMG_20210408_2208033032000Ă—1500 841 KB

Red 5 volt.
Brown GND
Orange GPIO13

IMG_20210408_220839027
IMG_20210408_2208390274000Ă—3000 2.54 MB

As you can see, no resistor. But when it was connected, it was bridged between red and orange on the “up” side, the resistor has been measured with a multimeter 3.3 Kohm.

What could be the issue?

2

Well, the documentation is quite clear that you will need a 4.7kΩ resistor between the data line and 3.3V. Have you tried adding one?

1 Like
3

The next sentence.

There are some saying no resistor and some day 1 Kohm, some say 10 Kohm.
I have tried pretty much everything

1 Like
4

change that to

dallas:
  - pin: GPIO13

You will also need to inject power on the data line w/ 4.7k

5

I use it with a 4K7 resistor and they work well.
I have several of them in operation on ESP and I use 3.3V power supply.
Do you have the power connected properly? What pins do you use for ESP?

6

Is your board type correct ? I looked on Platformio but could not see it. Does this work ?


board: ttgo-t5
7

I have. As stated in the first post, the resistor is bridged between red and orange cable.

I have also tried with GPIO13 no difference.

A 5 volt 2 A power supply connected to USB of ESP then using the pins to the sensor.
3.3 volt pin does not seem to work on the board. It only gives millivolts. The 5 volt pin gives 4.4 volt, so that is the one I use.
And GPIO13.

No that board type does not exist.

8

It seems the pinout is not correct.
This is the pinout for the board:

image
image1000Ă—707 142 KB

And using:

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO13
      mode: INPUT_PULLUP
    name: test

I could connect one wire to ground and probe around on the pins until I got a response in the log.
It seems GPIO13 is actually in the position where GPIO34 is in the pinout.

But using that pin, a 4.7 KOhm resistor and parasite mode still gives me no sensor found.

IMG_20210410_103354234_HDR
IMG_20210410_103354234_HDR4000Ă—3000 1.96 MB

From left the ESP.
Red 5 volt (4.5 volt)
Yellow data, GPIO 13 (The new GPIO13)
Brown GND

The dallas is connected black and red to GND and yellow to data with 4.7 KOhm resistor

9

This make no sense I don’t see how attaching the Vin to ground is going work. Do you have any other esp boards just to try the sensor on another platform. This shouldn’t be this complicated at this point I’d lean towards the board being incompatible. The other thing is set debug level to VERY_VERBOSE and post the output.

10

That is how parasite mode works.
https://www.google.com/search?q=ds18b20+parasitic+mode&client=ms-android-motorola-rvo3&sxsrf=ALeKk00dUmeO59z7RhTiVr6XeKFKGBsXJA%3A1618072529322&ei=0dNxYMyBE4yykwW_9oXYBw&oq=DS18b20+par&gs_lcp=ChNtb2JpbGUtZ3dzLXdpei1zZXJwEAEYATICCAAyBQgAEMsBMgUIABDLATIFCAAQywEyBQgAEMsBMgUIABDLATIFCAAQywEyBQgAEMsBOgQIABBHOgQIIxAnUNn5AViUjAJg1ZUCaAFwAXgAgAHWAYgB3QmSAQUyLjUuMZgBAKABAcgBCMABAQ&sclient=mobile-gws-wiz-serp

I have tried that logging level but nothing else is coming out.

11

There are some separate part numbers for parasitic operation, they end in -par. I don’t know that they are interchangeable. Which version do you have? Also are they DS18S or DS18B. It seems to me in the pdf’s, in parasite mode, the red on the sensor is not connected to anything.

https://www.digikey.com/en/products/detail/maxim-integrated/DS18S20-PAR/12121332

https://www.digikey.com/en/products/detail/maxim-integrated/DS18S20/11527020

12

That is not the same sensor.
I have the waterproof version.
https://pchbutik.se/komponenter/82-2-st-digital-vattentat-temperatur-givare-passar-arduino.html
The instructions on the page is to connect it in parasite mode

13

Have you tried adding the sensor component with the index variable?

sensor:
  - platform: dallas
    index: 0

Could you set the debug to very verbose and post the output?

Sorry I just translated the page and realized it has a model number 18B

e.
I should also note it does not say the exact chip used 18B or 18S… from the library that esphome links to

> DS18S20 - Please note there appears to be an issue with this series.

https://github.com/milesburton/Arduino-Temperature-Control-Library

14

I have tried to set an index be t that does not work either.
I can try it again on the “new pin”.
And I will try to connect it normal mode also and see what happens.

Lastly i will find another ESP and try it there.
Maybe I won’t have time for it all tonight but we’ll see.

15

I’m in tears now!

image
image745Ă—209 8.04 KB

So happy, so many hours…

Ok… If someone else has this issue, here is your problem.:

The pinout diagram is wrong on the TTGO T5 2.2 version.
If you only need one pin I suggest GPIO13. It’s the fourth pin from the SD card reader on the inner row.
Do not use parasite mode, connect it in normal mode.
5 volt on Vin.
GND och GND
Data -> 4.7 KOhm -> Vin

4 Likes
16

Bonjour Ă  tous,
Je rencontre le même problème.

esphome:
name: piscine
platform: ESP32
board: esp32dev

Enable logging

logger:
level: debug

Enable Home Assistant API

api:

ota:
password: “xxxxxxxxx”

wifi:
ssid: “xxxxxx”
password: “xxxxxxx”

Enable fallback hotspot (captive portal) in case wifi connection fails

ap:
ssid: “Piscine Fallback Hotspot”
password: “eV02f3h91ltt”

captive_portal:

dallas:

  • pin: GPIO13

update_interval: 10s

logs : ESPhome

image

Rouge = 5v
bleu = GND
Vert = Data

avec resistance 4k7 entre data et 5v

Sonde Modèle A : Capteur de température PT100 SUS304 G1/2 1/4 3/4 m8x1, 25 m10x1, 5 M12X1, sonde à filetage 1m, fil PVC à 3 cœurs en acier inoxydable | AliExpress

Avez vous des idées ? Merci d’avance

17

You should connect this to 3.3V instead.

And the resistor should be betweem data pin and 3.3V as described in the ESPHome documentation.

And, it would be really helpful if you could format your YAML code properly using the “Preformatted text” button next time.

18

Thank you for your feedback.
I have just tried with 3.3v without success :frowning:
Thanks for advice I will try to format my config next time.

image
image619Ă—518 39.1 KB

19

The sensor looks like a PT100 sensor based on the name and there is not mention that is DS18b20 in the link.
That is a calibrated resistive sensors and not a Dallas one wire sensor. So that will not work.

/Mattias

20

Merci pour ta réponse. Je ne comprends pas bien ce que tu veux dire. Est ce que tu peux me donner plus de précisions stp ? Merci d’avance