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enter image description hereI am using raspberry pi 4 model b and sensor DHT 11 for checking the humidity and temperature. When I am using the code DHT.py, the result is:

1604263139.922  4 3 0.0 0.0
1604263142.192  4 3 0.0 0.0
1604263144.463  4 3 0.0 0.0
1604263146.732  4 3 0.0 0.0
1604263149.002  4 3 0.0 0.0
1604263151.273  4 3 0.0 0.0
1604263153.544  4 3 0.0 0.0
1604263155.816  4 3 0.0 0.0

but when I run my own code by using the command of python3 q1.py -f 5 -p 20 -o test.csv :



from board import D4
import adafruit_dht
import argparse
import datetime

parser = argparse.ArgumentParser()

parser.add_argument('-f',type=float)
parser.add_argument('-p',type=float)
parser.add_argument('-o',type=str)

args = parser.parse_args()

num_samples = int(args.p / args.f )


dht_device = adafruit_dht.DHT11(D4)

fp = open(args.o, 'w')

for i in range(num_samples):
    now = datetime.datetime.now()
    temperature = dht_device.temperature
    humidity = dht_device.humidity
    ptint(now.day,temperature,humidity,file = fp)
    time.sleep(args.f)
    
fp.close()


the error is :



Traceback (most recent call last):
  File "q1.py", line 23, in <module>
    temperature = dht_device.temperature
  File "/home/pi/WORK_DIR/py37/lib/python3.7/site-packages/adafruit_dht.py", line 253, in temperature
    self.measure()
  File "/home/pi/WORK_DIR/py37/lib/python3.7/site-packages/adafruit_dht.py", line 205, in measure
    raise RuntimeError("DHT sensor not found, check wiring")
RuntimeError: DHT sensor not found, check wiring


the datasheet of sensor is DFR0067 DFROBOT enter image description here enter image description here

boot/config.txt

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
dtparam=i2c_arm=on
#dtparam=i2s=on
dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d
20
  • Your wiring is probably wrong (as suggested). It definitely SHOULDN'T be connected to 5V
    – Milliways
    Commented Nov 1, 2020 at 21:25
  • I corrected it but still isn't working
    – omid
    Commented Nov 1, 2020 at 21:32
  • Does Joan's code work? No one can tell what pins the module uses - there is no standard.
    – Milliways
    Commented Nov 1, 2020 at 21:35
  • 1
    put heatshrink tubing over the bare wire connectors
    – jsotola
    Commented Nov 1, 2020 at 21:42
  • 1
    It's a good idea to put the plastic shells on those dupont connectors as well. If the 5V and GND make contact, you'll have a fully baked raspberry pi on your hands.
    – PHimmel
    Commented Jan 5, 2021 at 7:10

2 Answers 2

1

I think (unless you have not corrected it yet) you have your wires wrong. The green one is the signal (data) and you have it connected to the 3V3.

Example how to connect to DFRduino

Source: DFRobot - SEN0137 DHT22 Temperature and humidity module

Hint: Try running it in the loop like in the dht_simpletest.py - as @Milliways mentioned the python library is not stable.

Running in the loop and printing exceptions will give you more debug info - for my Pi Zero v1.3 this message was printed among others - misreported, see: issue-33.

0

The Adafruit code is notoriously unreliable.

I use Joan's code, but have written a wrapper around it to facilitate getting a single reading.

This is easy to modify and include in your own code.

https://raspberrypi.stackexchange.com/a/117225/8697

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