Can't get DHT11 Sensor to work

[laurensguijt]

Hello guys,

After trying pretty much everything I still can't get the sensor temp to display. I have already tried disabling the use SUDO box. The libraries are installed and seem to be working correctly according to the testing script. See attached images underneath:

-Laurens

[DeathmannX]

Same here :(

[tanant]

I had a spare DHT11 so I connected it up, got the same issue, so will have a quick play with it this weekend if I get some time but to chase down a hunch @DeathmannX / @laurensguijt - in your cases, are you running your octoprint server under the pi username? (I'm not, but it'll just mean one less thing to worry about in your cases)

I'm guessing it's this:

• if you run this without sudo it should run as the pi user and have access to the adafruit_dht library but you need to be root to access the GPIO chip (I think)
• if you run it with sudo, then you have access to the GPIO chip, but you're running as root and won't have access to the relevant libraries.

if you want to give that a shot @laurensguijt - try the dht_simpletest but run with sudo, do you get something like this?

pi@octopi:/home/octo $ sudo python3 ~/foo.py
Traceback (most recent call last):
  File "/home/pi/foo.py", line 5, in <module>
    import board
ModuleNotFoundError: No module named 'board'

[F3n1x040]

hi I have the same problem, the sensor works well with the example in Python, but no data appears in the octoprint interface. it also happens to me with the CPU temperature sensor.I have tried both with sudo activated and without the.
thanks in advance for the help.
this is log:

2022-02-12 12:46:20,558 - octoprint.plugins.enclosure - WARNING - ######### current settings version None target settings version 10 #########
2022-02-12 12:46:20,558 - octoprint.plugins.enclosure - INFO - ######### Current settings #########
2022-02-12 12:46:20,559 - octoprint.plugins.enclosure - INFO - rpi_outputs: []
2022-02-12 12:46:20,559 - octoprint.plugins.enclosure - INFO - rpi_inputs: []
2022-02-12 12:46:20,559 - octoprint.plugins.enclosure - INFO - ######### End Current Settings #########
2022-02-12 12:46:20,559 - octoprint - ERROR - Error while trying to migrate settings for plugin enclosure, ignoring it
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint/init.py", line 523, in init_settings_plugin_config_migration_and_cleanup
implementation._identifier, implementation
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint/init.py", line 507, in settings_plugin_config_migration_and_cleanup
settings_migrator(settings_version, stored_version)
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint/util/init.py", line 1737, in wrapper
return f(*args, **kwargs)
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 162, in on_settings_migrate
if current >= 4 and target == 10:
TypeError: '>=' not supported between instances of 'NoneType' and 'int'
2022-02-12 12:46:23,931 - octoprint.plugins.enclosure - INFO - Detected Error in PrinterStateChanged id: ERROR state: Error will call listeners for shutdown_on_error!
2022-02-12 12:46:23,956 - octoprint.plugins.enclosure - INFO - Detected Error or Disconnect in Error will call listeners for shutdown_on_error!
2022-02-12 12:49:36,443 - octoprint.plugins.enclosure - WARNING - An exception of type ValueError occurred on log_error. Arguments:
('The channel sent is invalid on a Raspberry Pi',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1542, in configure_gpio
GPIO.setup(gpio_pin, GPIO.IN, pull_up_down=pull_resistor)
ValueError: The channel sent is invalid on a Raspberry Pi
2022-02-12 12:49:37,005 - octoprint.plugins.enclosure - INFO - Failed to execute python scripts, try disabling use SUDO on advanced section of the plugin.
2022-02-12 12:49:37,005 - octoprint.plugins.enclosure - WARNING - An exception of type ValueError occurred on log_error. Arguments:
('not enough values to unpack (expected 2, got 1)',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1126, in read_dht_temp
temp, hum = stdout.decode("utf-8").split("|")
ValueError: not enough values to unpack (expected 2, got 1)
2022-02-12 12:49:37,006 - octoprint.plugins.enclosure - WARNING - An exception of type UnboundLocalError occurred on log_error. Arguments:
("local variable 'airquality' referenced before assignment",)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1026, in get_sensor_data
if temp != -1 and hum != -1 and airquality != -1:
UnboundLocalError: local variable 'airquality' referenced before assignment
2022-02-12 12:49:37,006 - octoprint.plugins.enclosure - WARNING - An exception of type TypeError occurred on log_error. Arguments:
('cannot unpack non-iterable NoneType object',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 811, in check_enclosure_temp
temp, hum, airquality = self.get_sensor_data(sensor)
TypeError: cannot unpack non-iterable NoneType object
2022-02-12 12:49:47,090 - octoprint.plugins.enclosure - INFO - Failed to execute python scripts, try disabling use SUDO on advanced section of the plugin.
2022-02-12 12:49:47,091 - octoprint.plugins.enclosure - WARNING - An exception of type ValueError occurred on log_error. Arguments:
('not enough values to unpack (expected 2, got 1)',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1126, in read_dht_temp
temp, hum = stdout.decode("utf-8").split("|")
ValueError: not enough values to unpack (expected 2, got 1)
2022-02-12 12:49:47,092 - octoprint.plugins.enclosure - WARNING - An exception of type UnboundLocalError occurred on log_error. Arguments:
("local variable 'airquality' referenced before assignment",)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1026, in get_sensor_data
if temp != -1 and hum != -1 and airquality != -1:
UnboundLocalError: local variable 'airquality' referenced before assignment
2022-02-12 12:49:47,093 - octoprint.plugins.enclosure - WARNING - An exception of type TypeError occurred on log_error. Arguments:
('cannot unpack non-iterable NoneType object',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 811, in check_enclosure_temp
temp, hum, airquality = self.get_sensor_data(sensor)
TypeError: cannot unpack non-iterable NoneType object
2022-02-12 12:49:57,161 - octoprint.plugins.enclosure - INFO - Failed to execute python scripts, try disabling use SUDO on advanced section of the plugin.
2022-02-12 12:49:57,162 - octoprint.plugins.enclosure - WARNING - An exception of type ValueError occurred on log_error. Arguments:
('not enough values to unpack (expected 2, got 1)',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1126, in read_dht_temp
temp, hum = stdout.decode("utf-8").split("|")
ValueError: not enough values to unpack (expected 2, got 1)
2022-02-12 12:49:57,162 - octoprint.plugins.enclosure - WARNING - An exception of type UnboundLocalError occurred on log_error. Arguments:
("local variable 'airquality' referenced before assignment",)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1026, in get_sensor_data
if temp != -1 and hum != -1 and airquality != -1:
UnboundLocalError: local variable 'airquality' referenced before assignment
2022-02-12 12:49:57,163 - octoprint.plugins.enclosure - WARNING - An exception of type TypeError occurred on log_error. Arguments:
('cannot unpack non-iterable NoneType object',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 811, in check_enclosure_temp
temp, hum, airquality = self.get_sensor_data(sensor)
TypeError: cannot unpack non-iterable NoneType object
2022-02-12 12:50:07,242 - octoprint.plugins.enclosure - INFO - Failed to execute python scripts, try disabling use SUDO on advanced section of the plugin.
2022-02-12 12:50:07,244 - octoprint.plugins.enclosure - WARNING - An exception of type ValueError occurred on log_error. Arguments:
('not enough values to unpack (expected 2, got 1)',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1126, in read_dht_temp
temp, hum = stdout.decode("utf-8").split("|")
ValueError: not enough values to unpack (expected 2, got 1)
2022-02-12 12:50:07,245 - octoprint.plugins.enclosure - WARNING - An exception of type UnboundLocalError occurred on log_error. Arguments:
("local variable 'airquality' referenced before assignment",)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 1026, in get_sensor_data
if temp != -1 and hum != -1 and airquality != -1:
UnboundLocalError: local variable 'airquality' referenced before assignment
2022-02-12 12:50:07,245 - octoprint.plugins.enclosure - WARNING - An exception of type TypeError occurred on log_error. Arguments:
('cannot unpack non-iterable NoneType object',)
Traceback (most recent call last):
File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/init.py", line 811, in check_enclosure_temp
temp, hum, airquality = self.get_sensor_data(sensor)
TypeError: cannot unpack non-iterable NoneType object

[tanant]

heya @F3n1x040 (and anyone else watching) Lemme know if this works and I'll do a documentation PR at the very least.. There are two things I had to make sure of.

1. The Adafruit CircuitPython DHT python module is accessible to the user that is running octoprint
2. The user that is running needs to have access to the GPIO pins. TL;DR - probably needs to be part of the gpio group. (see note below though!)

Toggling sudo would solve the second, but would cause the first issue. If you have the library installed, but you lack access you'll see something like ... - octoprint.plugins.enclosure - DEBUG - Dht result: b'Unable to open chip: gpiochip0\n'

If you need to run with sudo?

1. Install the module system-wide.
   pi@blueberry_crumble:~ $ sudo pip3 install adafruit-circuitpython-dht
2. Enclosure should start picking up things now (you might need to reboot Octoprint, i don't think so but maybe. I forget)

If you don't need sudo, or don't want to run with it? (what i'm doing on my box)

1. In the terminal as the user that is running octoprint (pi in your case) install the module
   pi@blueberry_crumble:~ $ pip3 install adafruit-circuitpython-dht
2. then add the user pi to the gpio group (or dialout, see below)
   pi@blueberry_crumble:~ $ sudo usermod --append --groups gpio pi
3. At this point you'll probably need to reboot the RPi.

gpio or dialout?

I did find some links suggesting you need to be part of the dialout group - https://askubuntu.com/a/1313156 but on my RPi it's not dialout, it's gpio. Here's how I double checked:

pi@blueberry_crumble:~ $ less /etc/udev/rules.d/99-com.rules
...
...
SUBSYSTEM=="gpio", GROUP="gpio", MODE="0660"
SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", PROGRAM="/bin/sh -c 'chgrp -R gpio /sys/class/gpio && chmod -R g=u /sys/class/gpio'"
SUBSYSTEM=="gpio", ACTION=="add", PROGRAM="/bin/sh -c 'chgrp -R gpio /sys%p && chmod -R g=u /sys%p'"
...
...

I don't recall doing that, and that udev config is the same on my other RPi I use for a local DNS proxy.

[F3n1x040]

hello @tanant, I explain, I have verified that the user who runs octoprint is "pi" and that "pi" has access to GPIO pins.
pi@octopi:~/oprint/lib/python3.7/site-packages/octoprint_enclosure $ groups pi pi : pi adm tty dialout cdrom sudo audio video plugdev games users input netdev spi i2c gpio

if I run the command "systemctl status octoprint" I get the following:
pi@octopi:~/oprint/lib/python3.7/site-packages/octoprint_enclosure $ systemctl status octoprint
● octoprint.service - The snappy web interface for your 3D printer
Loaded: loaded (/etc/systemd/system/octoprint.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2022-02-14 19:40:23 CET; 12min ago
Main PID: 1304 (octoprint)
Tasks: 25 (limit: 1935)
CGroup: /system.slice/octoprint.service
└─1304 /home/pi/oprint/bin/python3 /home/pi/oprint/bin/octoprint serve --host=127.0.0.1 --port=5000

Feb 14 19:52:39 octopi octoprint[1304]: Traceback (most recent call last): Feb 14 19:52:39 octopi octoprint[1304]: File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/__init__ Feb 14 19:52:39 octopi octoprint[1304]: if temp != -1 and hum != -1 and airquality != -1: Feb 14 19:52:39 octopi octoprint[1304]: UnboundLocalError: local variable 'airquality' referenced before assignment Feb 14 19:52:39 octopi octoprint[1304]: 2022-02-14 19:52:39,633 - octoprint.plugins.enclosure - WARNING - An exception o Feb 14 19:52:39 octopi octoprint[1304]: ('cannot unpack non-iterable NoneType object',) Feb 14 19:52:39 octopi octoprint[1304]: Traceback (most recent call last): Feb 14 19:52:39 octopi octoprint[1304]: File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/__init__ Feb 14 19:52:39 octopi octoprint[1304]: temp, hum, airquality = self.get_sensor_data(sensor) Feb 14 19:52:39 octopi octoprint[1304]: TypeError: cannot unpack non-iterable NoneType object lines 1-18/18 (END)
From which I deduce that something happens with the variable "airquality"

When looking at the Octoprint log, the following warning and error lines appear:
2022-02-14 17:52:48,478 - octoprint.plugins.enclosure - INFO - Failed to execute python scripts, try disabling use SUDO on advanced section of the plugin. 2022-02-14 17:52:48,478 - octoprint.plugins.enclosure - WARNING - An exception of type ValueError occurred on log_error. Arguments: ('not enough values to unpack (expected 2, got 1)',) Traceback (most recent call last): File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/__init__.py", line 1126, in read_dht_temp temp, hum = stdout.decode("utf-8").split("|") ValueError: not enough values to unpack (expected 2, got 1) 2022-02-14 17:52:48,479 - octoprint.plugins.enclosure - WARNING - An exception of type UnboundLocalError occurred on log_error. Arguments: ("local variable 'airquality' referenced before assignment",) Traceback (most recent call last): File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/__init__.py", line 1026, in get_sensor_data if temp != -1 and hum != -1 and airquality != -1: UnboundLocalError: local variable 'airquality' referenced before assignment 2022-02-14 17:52:48,479 - octoprint.plugins.enclosure - WARNING - An exception of type TypeError occurred on log_error. Arguments: ('cannot unpack non-iterable NoneType object',) Traceback (most recent call last): File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/__init__.py", line 811, in check_enclosure_temp temp, hum, airquality = self.get_sensor_data(sensor) TypeError: cannot unpack non-iterable NoneType object

I'm using the plugin without "sudo", but I've tried using it with "sudo" and the log doesn't change
I have also installed the system-wide module both with the sudo command, and without the

I have tried to assign a value to the variable "airquality" in the code of the file "init.py" in the following line:

def get_sensor_data(self, sensor):
try:
if self.development_mode:
temp, hum, airquality = self.read_dummy_temp()
else:
if sensor['temp_sensor_type'] in ["11", "22", "2302"]:

airquality = 0

temp, hum = self.read_dht_temp(sensor['temp_sensor_type'], sensor['gpio_pin'])
elif sensor['temp_sensor_type'] == "18b20":
temp = self.read_18b20_temp(sensor['ds18b20_serial'])

But this causes the plugin not to load

[tanant]

From which I deduce that something happens with the variable "airquality"

Good spot, I'm not actually sure how it ends up there so we can look at it in a sec once we crush the first error that comes in a lot earlier - i have a suspicion that it's symptomatic rather than the thing we want to fix which is this:

File "/home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure/__init__.py", line 1126, in read_dht_temp temp, hum = stdout.decode("utf-8").split("|")
ValueError: not enough values to unpack (expected 2, got 1)

That suggests you're having trouble reading data from the sensor, the rest of the issues sort of cascade from that. To isolate this down, and take enclosure out of the picture, could you do the following?

• as the user pi try run the getDHTTemp.py script directly (it lives alongside the __init__.py file if you hadn't found it)

pi@blueberry_crumble: $ cd /home/pi/oprint/lib/python3.7/site-packages/octoprint_enclosure
pi@blueberry_crumble: $ python3 getDHTTemp.py 11 4
21.0 | 38.0

The 11 is for a DHT11 (22 is for a DHT22).
The 4 is which GPIO pin it's on.

If you supply a bad pin OR the wrong sensor then odds on it'll report -1 | -1.
If there's something wrong with your setup then this will error out. It'll either complain about an inability to load the adafruit_dht module OR that it can't open gpiochip0.

If it's the adafruit_dht module, it's the first step i mentioned.
If it's the gpiochip, then something in your setup is preventing access to the chip.
If it reads back correct data, then something else i'm not describing is happening - but we will know at least a portion of your setup is good.

(also, if the edits you've made cause the plugin to not load - I'm guessing the python you inserted has mixed spaces and tabs or has an indentation issue? Just a gut feeling.)

[F3n1x040]

hello @tanant, I have done the test you told me and it has worked correctly.
pi@octopi:~/oprint/lib/python3.7/site-packages/octoprint_enclosure $ python3 getDHTTemp.py 11 4
16.0 | 61.0
I have edited the code as it says in the issue you mentioned and it has worked correctly. As you told me I had mixed tabs with spaces in the code and that caused the plugin not to load, my mistake by novice hehe.
Thank you very much for the help

[tanant]

Ah, awesome, so does everything now work and you're getting proper readouts in enclosure? If so, was did you end up needing to change from a standard install?

[F3n1x040]

I don't know what to answer you. I did a standard installation with the octoprint manager plugin, then followed the steps indicated for the DHT11, DHT22 and AM2302 sensors as indicated by the readme.md and in the end I had to modify the file __init__.py adding the line airquality = 0 as described by @manuelwolfcgm in issue #453
So it could be said that I did have to modify the standard installation

It also happens to me what @plani-de in issue #453, but I get the feeling that this is caused by some kind of conflict with some other script that tries to access the GPIOS or an intermittent failure in sensor communication because when I run the test script https://learn.adafruit.com/dht-humidity-sensing-on-raspberry-pi-with-gdocs-logging/python-setup to test the DHT11 sensor this happens:
pi@octopi:~/proyectos/RaspberryPi-DHTxx $ python3 dht_prueba.py
Temp: 57.2 F / 14.0 C Humidity: 63%
Temp: 57.2 F / 14.0 C Humidity: 63%
A full buffer was not returned. Try again.
Temp: 57.2 F / 14.0 C Humidity: 63%
Anyway although this happens, I have not found that it affects the functionality of the plugin for now

[tanant]

Ooooo, hang about, you know what's probably confusing me? #461 was merged about a month ago, and that has the airquality changes in it and i've been doing a mess of local edits so i had picked them up too.

I think somewhere between my notes above, and #461 it should be fixed but while those changes have been merged into master the latest release is 4.13.2 which doesn't have those in them.

[F3n1x040]

hello, things that happen hehe. the good thing you already know is what has happened.
My thanks for your plugin and your work as well.
Best regards

[matthenning]

For anyone struggling with this, I had to fix two things:

First: Even though the dependencies were installed as root and as pi user, I only got it working after disabling sudo mode

Second: The getDHTTemp.py script had a trailing line in its output, which I had to remove by adding .splitlines()[0] in the __init__.py mentioned by @tanant in the read_dht_temp function:

temp, hum = stdout.decode("utf-8").splitlines()[0].split("|")

Without the second fix humidity was always reported as 0%
I couldn't figure out where exactly the trailing line is coming from. According to superficial research it could be related to not exiting the DHT device after reading. But calling dhtDevice.exit() will generate a different trailing line.

Hope that helps someone.