DHT22 Sensor with a Duex5

  • I am attempting to configure a DHT22 sensor (this model: https://www.amazon.com/gp/product/B01N9BA0O4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1), and I also have a Duex5 attached to my Duet Wifi. By my understanding, the data pin on the sensor should be attached to pin CS6, i.e. the E3 endstop line. So I have made a connector that plugs into the E3 endstop slot on the Duex5, where I am pulling both a positive voltage and ground for the sensor in addition to connecting the data line. With this setup, I have had no luck getting the sensor to work in DWC; it always shows 2000 degrees and 2000% for humidity.

    I am setting up the sensor as follows:
    M305 P103 X400 T22 S"Chamber Temperature"
    M305 P104 X401 T22 S"Chamber Humidity [%]"

    I am running firmware 2.0(RTOS)RC5 with wifi server version 1.21.

    I have verified the module does work on its own using a Raspberry Pi. I have tried using both 3.3 and 5 volts for the endstop power on the Duex5, with no change in the results. I have verified the connections from the Duex5 to the sensor using a multimeter. I have tried a basically blank config.g file with only the preamble setting up the network and the gcode lines I gave above to configure the sensors, and I had no luck there either.

    Is there something I am missing here? I am wondering if the fact I have a Duex5 attached is somehow blocking the CS6 pin to be used for this.

    Thanks for your help!

  • administrators

    That's not going to work, because the E3 endstop input on the DueX5 is not routed to CS6. Pick up CS6 on the SPI daughter board header on the DueX5 instead.

  • Thanks, that did the trick! I'm sorry, I misunderstood the documentation on the gcode page (it states "(was E3 Endstop on the expansion header)"). I can see now after looking at the pinout table how I incorrectly interpreted that.

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