DHT11 not working properly

Using version 3.5.8 in a loop it almost never gets a reading with the following code:

import time
import board
import adafruit_dht

dhtDevice = adafruit_dht.DHT11(board.PG6)


for try_number in range(1,200):
  print(f"Try number {try_number}")
  try:
    print(f"Got temp of: {dhtDevice.temperature}")
    print(f"And hum of: {dhtDevice.humidity}")
    break
  except RuntimeError as e:
    print(e)
    time.sleep(2.1)
  else:
    time.sleep(2.1)
  print("\n")

The weird part is that using the version 3.5.5 it actually get the readings correctly.

More data: Python: 3.8.5 SBC: Orange Pi Lite Installed libraries:

Adafruit-Blinka==6.4.1
adafruit-circuitpython-busdevice==5.0.6
adafruit-circuitpython-dht==3.5.5
adafruit-circuitpython-mcp3xxx==1.4.5
Adafruit-PlatformDetect==3.4.0
Adafruit-PureIO==1.1.8
appdirs==1.4.4
attrs==20.3.0
bcrypt==3.2.0
cached-property==1.5.2
certifi==2019.11.28
cffi==1.14.3
chardet==3.0.4
cryptography==3.2.1
dbus-python==1.2.16
distlib==0.3.1
distro==1.5.0
distro-info===0.23ubuntu1
docker==4.3.1
docker-compose==1.27.4
dockerpty==0.4.1
docopt==0.6.2
filelock==3.0.12
idna==2.8
iotop==0.6
jsonschema==3.2.0
mudpi==0.10.0
paho-mqtt==1.5.1
paramiko==2.7.2
pycparser==2.20
pyftdi==0.52.9
PyGObject==3.36.0
PyNaCl==1.4.0
pyrsistent==0.17.3
pyserial==3.5
python-apt==2.0.0+ubuntu0.20.4.4
python-dotenv==0.15.0
pyusb==1.1.1
PyYAML==5.3.1
redis==3.5.3
requests==2.22.0
requests-unixsocket==0.2.0
six==1.14.0
texttable==1.6.3
unattended-upgrades==0.1
urllib3==1.25.8
virtualenv==20.1.0
websocket-client==0.57.0

[yeyeto2788]

I hope it is a DHT11 because it actually looks like one, my sensor is this one which was bought on other site.

Regarding that datasheet it states the following:

the programme of MCU will set Data Single-bus voltage level from high to low and this processmust take at least 18ms to ensure DHT’s detection of MCU’s signal

So it has to be AT LEAST 18ms and I’m actually getting better results with less than that (1.85ms)🤮

If you need me to test something else just let me know.

P.D: I can also contact me through Discord and probably it would be more faster.

[olixr]

I wanted to add some testing to help give more data. I have a RPi4 that works fine with both the DHT11 and DHT22. I also have a RPi zero w but it has more trouble getting reads from both the DHT11 and DHT22. I thought I would run tests on the zero and see if it helps reveal more on the timings.

Here are some details:

Installed packaged

Package                          Version
-------------------------------- -------------------
Adafruit-Blinka                  6.4.1
adafruit-circuitpython-74hc595   1.2.4
adafruit-circuitpython-bme680    3.3.2
adafruit-circuitpython-busdevice 5.0.6
adafruit-circuitpython-charlcd   3.1.2.dev7+g07007b4
adafruit-circuitpython-debouncer 1.3.10
adafruit-circuitpython-dht       3.5.8
adafruit-circuitpython-mcp230xx  2.4.5
Adafruit-PlatformDetect          3.4.1
Adafruit-PureIO                  1.1.8
asn1crypto                       0.24.0
certifi                          2018.8.24
chardet                          3.0.4
cryptography                     2.6.1
entrypoints                      0.3
idna                             2.6
keyring                          17.1.1
keyrings.alt                     3.1.1
mudpi                            0.10.0
numpy                            1.16.2
paho-mqtt                        1.5.1
pip                              18.1
pycron                           3.0.0
pycrypto                         2.6.1
pyftdi                           0.52.9
PyGObject                        3.30.4
pyserial                         3.5
python-apt                       1.8.4.3
pyusb                            1.1.1
pyxdg                            0.25
PyYAML                           5.4.1
redis                            3.5.3
requests                         2.21.0
rpi-ws281x                       4.2.6
RPi.GPIO                         0.7.0
SecretStorage                    2.3.1
setuptools                       40.8.0
six                              1.12.0
ssh-import-id                    5.7
sysv-ipc                         1.1.0
urllib3                          1.24.1
wheel                            0.32.3

Board: RPi Zero W Python: 3.7.3

Test Script Results

RPi Zero W DHT22 (Range: 500 - 2000) (Increments: 100)
Maximum reads: 10  out of 10 with the following times: 1000, 1900


RPi Zero W DHT11 (Range: 15000 - 24800) (Increments: 100)
Maximum reads: 10  out of 10 with the following times: 15100, 15300, 15400, 15500, 16800, 17000, 17200, 17300, 18900, 19900, 20000, 20200, 20600, 21000, 22200, 22700, 24100