I've noticed when my sense hat is in direct sunlight the humidity reading immediately drops. In very bright sunlight it actually reads negative values. The change in readings is almost instantaneous. I've also noticed that if I shine my LED flashlight on the sensor it has no effect, but a flashlight with an incandescent bulb does. I put a small piece of black packing foam / sponge over the sensor and it then reads normally. This on a Pi A+ running Raspbian Stretch, fully updated. My code is all done in python.
` import os import time, datetime from sense_hat import SenseHat, ACTION_PRESSED, ACTION_HELD, ACTION_RELEASED

sense = SenseHat() sense.set_rotation(180) sense.set_imu_config(False, False, False) sense.low_light = True

s=(0.065) # scroll speed w=(0) # color all white toggle x=(2) #shutdown variable

is really stick down

def pushed_up(event): if event.action == ACTION_PRESSED: sense.low_light = True

is really stick up

def pushed_down(event): if event.action == ACTION_PRESSED: sense.low_light = False

is really stick right

def pushed_left(event): global w if event.action == ACTION_PRESSED: w = (255)

is really stick left

def pushed_right(event): global w if event.action == ACTION_PRESSED: w = (0)

def pushed_middle(event): global x if event.action == ACTION_PRESSED: x = 0

sense.stick.direction_up = pushed_up sense.stick.direction_down = pushed_down sense.stick.direction_left = pushed_left sense.stick.direction_right = pushed_right sense.stick.direction_middle = pushed_middle

while True:

dateString = "%A %B %-d %-I:%M:%p"
msg = "It is %s" % (datetime.datetime.now().strftime(dateString))
sense.show_message(msg, scroll_speed=s, text_colour=(w, 255, 255))

t = sense.get_temperature()
t = round(t)

if t <= 0: 
    tc = [w, w, 255]  # Blue
elif t > 0 and t < 13:
    tc = [255, 255, w]  # Yellow
elif t >= 13 and t <= 25:
    tc = [w, 255, w]  # Green
elif t > 25:
    tc = [255, w, w]  # Red                 
msg = "and %sc" % (t)
sense.show_message(msg, scroll_speed=s, text_colour=tc)

h = sense.get_humidity()
h = round(h)

if h < 0:
    h = 0

if h > 100:
    h = 100

if h < 30:
    hc = [255, w, w]  # Red
    msg = "with %s%% Humidity" % (h)
    sense.show_message(msg, scroll_speed=s, text_colour=hc)
elif h >= 30 and h <= 60:
    hc = [w, 255, w]  # Green
    msg = "with %s%% Humidity" % (h)
    sense.show_message(msg, scroll_speed=s, text_colour=hc)
elif h > 60 and h < 80:
    hc = [255, 255, w]  # Yellow
    msg = "with %s%% Humidity" % (h)
    sense.show_message(msg, scroll_speed=s, text_colour=hc)
elif h >= 80:
    hc = [255, w, w]  # Red
    msg = "with %s%% Humidity" % (h)
    sense.show_message(msg, scroll_speed=s, text_colour=hc)

p = sense.get_pressure()
p = round(p)

if p > 0 and p < 985:
    pc = [255, w, w]  # Red
    msg = "- Barometer is Very Low @ %smb - Storm Watch" % (p)
    sense.show_message(msg, scroll_speed=s, text_colour=pc)
elif p >= 985 and p < 1005:
    pc = [255, 255, w]  # Yellow
    msg = "- Barometer is Low @ %smb - Possible Percipitation" % (p)
    sense.show_message(msg, scroll_speed=s, text_colour=pc)
elif p >= 1005 and p < 1025:
    pc = [w, 255, w]  # Green
    msg = "- Barometer is Mid Range @ %smb" % (p)
    sense.show_message(msg, scroll_speed=s, text_colour=pc)
elif p >= 1025 and p < 1050:
    pc = [w, w, 255]  # Blue
    msg = "- Barometer is High @ %smb" % (p)
    sense.show_message(msg, scroll_speed=s, text_colour=pc)
elif p >= 1050:
    pc = [255, w, w]  # Red
    msg = "- Barometer is Very High @ %smb - Expect Dry Conditions" % (p) 
    sense.show_message(msg, scroll_speed=s, text_colour=pc)

if x == 0:
    sense.clear()
    os.system("sudo shutdown now -P")
    time.sleep(30)

raspberrypi / rpi-sense

Humididty sensor sensitive to light #8

is really stick down

is really stick up

is really stick right

is really stick left