Is Enviro HAT working for you reliably?

Question

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

feiticeir0 · Answer

Hi Victoria.

I'm going to guess that the problem may be the connections - maybe the jumper wires are not well connected to the PINs or some may be faulty ? I had problems before with loose jumper wires.

Can you test it by snap the two together ?

Mine is working fine without those reading swings.

Try and test both snapped to see.

skruglewicz · Answer

Hi ilvyanyatka 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

ilvyanyatka · Answer

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

skruglewicz · Answer

Hi ilvyanyatka Thanks so much for checking out my blog. To answer your question, the code in the script is using a Python Classes from sensors.py. The code for this class can be viewed in my blog testing my classes at Blog# 8.1 (Part 1 of 2) EAS - System Build specifically at this location RoomHumidity class in the blog I will eventually post my entire source code up to a Git Repository, soon. I recall during testing, the script that checks the humidity, rose as the water in the glass container was running. Hope this answers your initial question Steve K

feiticeir0 · Answer

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.

ilvyanyatka · Answer

Thank you. I use the same code to get the values. I guess my sensor is just defective. I just don't see another explanation for such a big swing in values.

Is Enviro HAT working for you reliably?

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