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Is Enviro HAT working for you reliably?

ilvyanyatka

Hello,

I am having issues with Enviro HAT humidity and temperature sensors. I wonder if mine is defected or if I am missing something on how to use it. It is not snapped on Raspberry PI but connected by jumper wires.

1) The first humidity reading is often (not always) more than 90, the second and so on drops down to 30-40

2) In the same room 2 minutes apart humidity value can change up to 15 points. For example, first reading - 42, second - 27

3) Temperature value drops much below real value if humidity grows. For example, in the same room with 22C/40% humidity, if humidifier is running, next reading it 10 minutes will show 16C/55% humidity

 

Do you have any idea why?

TIA

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  • 0

    Hi

     

    I have the enviro hat connected with jumper wires and the sensor is behaving reasonable well

    in My blog# 10 at this location    I describe my script to check the Humidity in the growing house.

     

    lI recall the test retuning different readings for Humidity, but the screenshots only display 88%?

    I display the Humidity over time in my chart HERE

     

    I'm away from my project this week but I'll see if I'm getting the same values as you describe.

    when I get a chance.

    Regards

    Steve

  • 0 in reply to skruglewicz

    Thank you Steve!

     

    What exactly is in your code for

    value = RoomHumidity.getValue()

     

    Do you use bme280 object to access Enviro sensor?  Something like

        bus = SMBus(1) 

       bme280 = BME280(i2c_dev=bus)

        AirHumidity = bme280.get_humidity()

       

    Or do you use some other library/object?

     

    Victoria

  • 0 in reply to ilvyanyatka

    This may seem a dumb question, but have you tried with the Pimoroni's examples ?

     

    Because - in their examples - the sensor sits on top of the Raspberry PI, they perform some calculations to remove the average cpu temperature to give a sort of accurate reading of the ambient temperature. and you don't have it that way.

     

    Here's my code, a simple one to read the temperature/humidity (without giving in to cpu temperature):

    import time
import sys

from bme280 import BME280


bme280 = BME280()


try:

    while True:
        # get data
        print ("Temp: {}".format(bme280.get_temperature()))
        print ("Hum: {}".format(bme280.get_humidity()))

        time.sleep(5)
except KeyboardInterrupt:
    sys.exit(0)

     

    And a run of it for 60 seconds:

     

    Temp: 22.631540955626406
Hum: 78.25451136740215
Temp: 31.840742193745086
Hum: 26.63692386637497
Temp: 31.831073930848675
Hum: 26.830281509600262
Temp: 31.831718481676603
Hum: 26.85365856716121
Temp: 31.834618960458556
Hum: 26.818467172909095
Temp: 31.838486265644406
Hum: 26.75399488327368
Temp: 31.834618960458556
Hum: 26.91790856236235
Temp: 31.83913081652463
Hum: 26.683776162340155
Temp: 31.834618960458556
Hum: 26.818467172909095
Temp: 31.825595248994887
Hum: 26.871405382322422
Temp: 31.832040757092273
Hum: 26.567011411920134
Temp: 31.829140278392174
Hum: 26.812795837825956

     

    I have it on top of the RPI, so, the values are acceptable.

    I really don't have the swings of values you describe.

     

    Just try the code and see.

  • 0 in reply to feiticeir0

    Yes, it is the exact code I am using.

    I don't adjust temperature When Enviro was snapped on, the temperature reading was a couple of degrees higher. Now it seems to be accurate when humidity is around 30%. It starts returning wrong values when humidity is over 50%.

     

    Thank you for your help. I guess my sensors are just a bit defective.

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  • 0 in reply to feiticeir0

    Yes, it is the exact code I am using.

    I don't adjust temperature When Enviro was snapped on, the temperature reading was a couple of degrees higher. Now it seems to be accurate when humidity is around 30%. It starts returning wrong values when humidity is over 50%.

     

    Thank you for your help. I guess my sensors are just a bit defective.

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