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Wiring DHT11 to Raspberry pi - Printable Version

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Wiring DHT11 to Raspberry pi - hcccs - Feb-05-2021

I'm struggling with this simple setup with DHT11. I have wired in the 3-wire DHT11 sensor like this on my RP 2 model B version 1:
Vcc > pin 2 (5V)
Gnd > pin 9 (GND)
Data > pin 7 (GPIO 4)
and I keep getting "DHT sensor not found, check wiring"
I couldn't find a symbol for the 3-wire sensor so disregard the 4th pin.
I have installed the Adafruit_CircuitPython_DHT library.

    # SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
    # SPDX-License-Identifier: MIT
     
    import time
    import board
    import adafruit_dht
     
    dhtDevice = adafruit_dht.DHT22(board.D4)
     
    while True:
        try:
            temperature_c = dhtDevice.temperature
            temperature_f = temperature_c * (9 / 5) + 32
            humidity = dhtDevice.humidity
            print(
                "Temp: {:.1f} F / {:.1f} C    Humidity: {}% ".format(
                    temperature_f, temperature_c, humidity
                )
            )

        except RuntimeError as error:
            # Errors happen fairly often, DHT's are hard to read, just keep going
            print(error.args[0])
            time.sleep(2.0)
            continue
        except Exception as error:
            dhtDevice.exit()
            raise error

        time.sleep(2.0)
Error:
DHT sensor not found, check wiring
[Image: DHT11.png]

I ran a debug on the code.

Output:
adafruit_dht	<module 'adafruit_dht' from 'home/pi/.local/lib/python3.7/site-packages/adafruit_dht
board			<module 'board' from '/usr/local/lib/python3.7/dist-packages/board.py'>
dhtDevice		<adafruit_dht.DHT11 object at <0x757727b0>
time			<module 'time' (bulit-in)>
The '<0x757727b0>' looks like some kind of address. Could it be something to check? It looks like it has found the sensor after all so why doesn't it work?

RE: Wiring DHT11 to Raspberry pi - Jeff900 - Feb-05-2021

And have you checked the wiring already? Smile

RE: Wiring DHT11 to Raspberry pi - Larz60+ - Feb-05-2021

using the pinout diagram here: https://pi4j.com/1.2/pins/model-2b-rev1.html
diagram shows pin7 as GPIO 7, not GPIO 4

RE: Wiring DHT11 to Raspberry pi - hcccs - Feb-06-2021

(Feb-05-2021, 11:07 PM)Larz60+ Wrote: using the pinout diagram here: https://pi4j.com/1.2/pins/model-2b-rev1.html
diagram shows pin7 as GPIO 7, not GPIO 4

It's difficult to know what information you can trust. I used the pinout from https://pinout.xyz/# and it differs from the one you mentioned. I changed the IO number now to 4 but it's the same. I also tried running the DHT11 off 5V and 3.3 but it makes no difference.