Sense Hat Environmental Sensors

Question

Hi, I received my package today and was testing Sense Hat. I wrote a small script to log the values to screen. # Test for environmental sensors

from sense_hat import SenseHat
from time import sleep

sh = SenseHat()

try:
 while True:
 t = sh.get_temperature()
 p = sh.get_pressure()
 h = sh.get_humidity()

t = round( t, 1 )
 p = round( p, 1 )
 h = round( h, 1 )

print( "Temp = %s Prsr = %s Hmdt = %s" %(t,p,h) )
 sleep( 1 )

except KeyboardInterrupt:
 print( "Exiting..." ); But I am getting negative values for temperature and humidity. Temp = -422.2
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.6
Prsr = 1008.2
Hmdt = -39.8
Temp = -421.5
Prsr = 1008.2
Hmdt = -39.7
Temp = -422.0
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.1
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.0
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.0
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.1
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.1
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.1
Prsr = 1008.2
Hmdt = -39.8
Temp = -422.1
Prsr = 1008.2
Hmdt = -39.8 Can anyone tell me what is it I'm doing wrong? Thanks, vish

fvan · Accepted Answer

According to https://www.raspberrypi.org/forums/viewtopic.php?f=104&t=148103&start=50 it is most likely a HW issue. I'll check mine later today ... Frederick Edit: Quickly plugged it in and copy/pasted your code. Results are positive and stable: pi@raspberrypi:~ $ sudo python sensehat.py
Temp = 35.3 Prsr = 0.0 Hmdt = 29.4
Temp = 35.3 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.3 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.5 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.3 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.3 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.5 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.3 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.5 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.5 Prsr = 1021.9 Hmdt = 29.4
Temp = 35.4 Prsr = 1021.9 Hmdt = 29.4
^CExiting...

fvan · Answer

Confirmed as HW issue on RPi forums. Some distributors may have stock of faulty units, so that's what we're probably suffering from ... element14Dave

https://www.raspberrypi.org/forums/viewtopic.php?f=104&t=148103&start=50

fvan · Answer

vish , I suspect something me be wrong with your humidity sensor (and now mine??). An alternative way for temperature, is to retrieve it from the pressure sensor: #t = sh.get_temperature()
t = sh.get_temperature_from_pressure() That should help you getting 2 out of 3 values Frederick

Sense Hat Environmental Sensors

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