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Wemos d1 ESP8266 + DHT22 sensor. Each sensor shows different values.

wojtaszek171 906 4
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  • #1 19670147
    wojtaszek171
    Level 5  
    Hello,
    I am building myself a simple home management and information display panel (smart home). I have invested in 5 DHT22 sensors and 1 BME280. I have built 5 microcontrollers from this.
    1. socket control, waterproof temperature probe and DHT22
    2,3,4. DHT22
    5. DHT22 and BME280
    I connected everything according to schematics found on the internet with 10k between VCC and data.
    I soldered everything together to start using it, I left it connected overnight so that each sensor lay in the same place and unfortunately each sensor shows different values. (Analogue thermometer showed 23.6 degrees)
    Initially I wrapped the circuits with insulating tape but ultimately they were to have their own boxes.
    I'm a bit disappointed with how it looks. I hope someone here can help me with this problem.

    The code for circuits 2,3 and 4. The rest of the circuits take DHT similarly:
    Link to github .
    Wemos d1 ESP8266 + DHT22 sensor. Each sensor shows different values.
    .
    Wemos d1 ESP8266 + DHT22 sensor. Each sensor shows different values.
    .
    Wemos d1 ESP8266 + DHT22 sensor. Each sensor shows different values.
    .
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  • #2 19670172
    varaktor
    Level 18  
    These sensors are just poor. I had the same thing a while ago, basically the only use for these DHTs is a housing into which you can put some better sensor.
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  • #3 19670198
    khoam
    Level 42  
    Chips with DHT22 (AM2302) should be calibrated by software. Most of them are Chinese clones.
    There are some articles on the internet on this subject. Examples:
    Link .
    Link .
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  • #4 19670833
    wojtaszek171
    Level 5  
    varaktor wrote:
    These sensors are just poor. I had the same thing a while ago, basically the only use for these DHT's is a housing into which you can put some better sensor.
    .
    Would you recommend perhaps a better inexpensive sensor? BME280 is quite expensive at the moment but also the results are not accurate.
  • #5 19671520
    ex-or
    Level 28  
    The sensor for what? The temperature itself is a DS18B20 - accurate and easy to apply. Humidity? Rumour around town is that the Honeywell HIH6131 is good.
    Maybe different - the Bosch is, in my opinion, quite good for humidity and pressure measurements, but the temperature measurement serves, it seems to me, to compensate for humidity readings. So I wouldn't expect miracles and temperature is unlikely to be output on the display.
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