Humidity/Temp Sensor Issues

  • This is my second humidity sensor.

    I keep getting the same error.
    Failed reading temperature from DHT
    Failed reading humidity from DHT

    1. I have tried 4 different DHT22 and even the one off my working Humidity sensor
    2. I have tried 5 different mini pros with only my original working..
    3. My original has a blue LED but the others were ordered in a ten pack and have red LED.
    4. Some of the red LED mini pro will only connect @ 57600 while others and blue LED connect @ 115200
    5. Changing the input pin for the DHT22 makes no difference.

    Do I just have a bunch of bad Mini Pros or am I missing something?

    FullSizeRender_1.jpg FullSizeRender_2.jpg FullSizeRender.jpg

  • Mine was doing the same thing when I had it plugged into my laptop while viewing the serial monitor. Once I connected it to my Gateway and into Vera, all is working. I got really frustrated at this, but it just seemed like it wanted to be connected to something first.
    Sorry, probably not much help, but thought I would share my experience.

  • Perhaps your minis are 3.3v 8 Mhz and you selected 5v 16 Mhz in the IDE?

  • these are all 5.5v 16mhz or at least that's what they
    ill try leaving it set up on the gateway and see what happens with fingers crossed

  • When you apply voltage to the RAW pin, do you get 5v out of Vcc?

  • @Salmoides 5v regulated into raw comes out 4.52v on vcc

  • Contest Winner


    have you tried to put a cap on the DHT's Vcc and ground??

  • @BulldogLowell Yes. I put one 4.7uf for the radio and one for the DHT22 with no change. Over two days I did get it to read the DHT22 once out of 1000 or so reads and that was with out any capacitors.. Reading every 5 seconds

  • I have a similar problem with a pack of 10 pro mini 3,3v bought at the ebay link from mysensor ?
    But every think is ok with pro mini 5.5v ...
    I tried many things but it still do not work ?
    Other people with same problem ?
    Ideas ?

  • Admin

    @ludoarchi said:

    I have a similar problem with a pack of 10 pro mini 3,3v bought at the ebay link from mysensor ?

    Only problem with humidiy sensor or a more general problem?

    Googling 3.3v dht22 giver a lot of results. E.g.

  • Problem with dht22 and ds18b20.
    It looks likes a programmation beceause i just switch from arduino pro 3.3 to a 5.5 on my mys1.1 board and it works fine.
    Or it s really a problem of manufacturing ...

  • Hero Member

    I've a sensor running with naked 328p, 3.3V, 8 MHz internal Osz and DHT22. Maybe I'm lucky?!

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