[RPI/Python] Raspberry PI Weather station using SenseHat

OK, since I broke the first one during a firmware upgrade, I thought I should document this.

So, here are the hardware requirements:

Raspberry Pi model 3B
MicroSD Card of about 16GB
Power Supply
Sense HAT
Ethernet cable or use the onboard Wi-Fi

Download the latest version of the Pi Installer – https://www.raspberrypi.com/software/ and flash your SD Card with the latest version

Once you have the SD Card ready, put it in your Raspberry Pi and boot.

I won’t go into configuring the network on the Pi, since it’s GUI. Just configure your network and put the OS to boot into CLI.

OK, now on with the software:

upgrade
install the Sense HAT software

sudo apt-get update
sudo apt-get upgrade

sudo apt-get install sense-hat
sudo reboot

sudo apt-get update

sudo apt-get upgrade

sudo apt-get install sense-hat

sudo reboot

Now we have the software installed we need to write a quick script to ensure the Sense HAT is working correctly.
We can start writing this script by entering the following command.

sudo nano ~/sensehat_test.py

1	sudo nano ~/sensehat_test.py

Write the following lines into this file, and we will explain what each section of code does as we go.

from sense_hat import SenseHat

1	from sense_hat import SenseHat

This line imports the Sense Hat module from the sense_hat library. This library allows us to interact with the Hat itself through python.

sense = SenseHat()

1	sense = SenseHat()

This line creates a link to the Sense Hat library and initializes itself so we can start making calls to it.

sense.show_message("Hello World")

1	sense.show_message("Hello World")

This line writes a message to the Sense Hat, and you should see “Hello World” scroll across the RGB lights.

Press CTRL + X then Y then press ENTER to save the file.

With the file now saved we can run it with the following command:

sudo python ~/sensehat_test.py

1	sudo python ~/sensehat_test.py

The text “Hello World” should now scroll across the RGB LEDs on top of the Sense HAT. If it doesn’t, it is likely that the HAT has not been properly pressed down on top of the GPIO pins.

If it is still not working, try restarting the Raspberry Pi by rerunning the following command.

sudo reboot

1	sudo reboot

Now here’s the full Python script I used to get the date, time, Temperature in Celsius degrees, Pressure in mmHg and Humidity in percents:

#import modules
from sense_hat import SenseHat
from datetime import date, datetime

import time
import sys

sense = SenseHat()
sense.clear()

try:
      while True:
           #Get values from SenseHat Sensors
           temp = sense.get_temperature()
           temp = round(temp, 1)
           print("Temperature C",temp)

           humidity = sense.get_humidity()
           humidity = round(humidity, 1)
           print("Humidity :",humidity)

           pressure = sense.get_pressure()
           pressure = round(pressure, 1)
           pressureMMHG = pressure * 0.750063755419211
           floatPressureMMHG = round(pressureMMHG, 2)
           print("Pressure:",floatPressureMMHG)

           # Month abbreviation, day and year
           today = date.today()
           d4 = today.strftime("%b-%d-%Y")
           print("Current Date is: ", d4)

           # Get time
           now = datetime.now()
           current_time = now.strftime("%H:%M:%S")
           print("Current Time is: ", current_time)

           #Sample print in oneline
           #sense.show_message("Temperature C" + str(temp) + "Humidity:" + str(humidity) + "Pressure:" + str(pressureMMHG), scroll_speed=(0.08), back_colour= [0,0,200])

           #Defining colours
           blue = (0, 0, 255)
           red = (255, 0, 0)
           orange = (255, 165, 0)
           yellow = (255, 255, 0)
           green = (0, 255, 0)
           blue = (0, 0, 255)
           purple = (160, 32, 240)


           #Print On SenseHat Matrix // the lower the value, the faster it moves
           sense.show_message ("Date: " + str(d4),  scroll_speed=(0.07), text_colour=purple)
           sense.show_message ("Time: " + str(current_time),  scroll_speed=(0.07), text_colour=yellow)
           sense.show_message("C: " + str(temp), scroll_speed=(0.10), text_colour=red)
           sense.show_message("Humidity % " + str(humidity), scroll_speed=(0.10), text_colour=blue)
           sense.show_message("mmHg: " + str(floatPressureMMHG), scroll_speed=(0.10), text_colour=orange)



           time.sleep(1)
except KeyboardInterrupt:
      pass

sense.clear()

#import modules

from sense_hat import SenseHat

from datetime import date, datetime

import time

import sys

sense = SenseHat()

sense.clear()

try:

while True:

#Get values from SenseHat Sensors

temp = sense.get_temperature()

temp = round(temp, 1)

print("Temperature C",temp)

humidity = sense.get_humidity()

humidity = round(humidity, 1)

print("Humidity :",humidity)

pressure = sense.get_pressure()

pressure = round(pressure, 1)

pressureMMHG = pressure * 0.750063755419211

floatPressureMMHG = round(pressureMMHG, 2)

print("Pressure:",floatPressureMMHG)

# Month abbreviation, day and year

today = date.today()

d4 = today.strftime("%b-%d-%Y")

print("Current Date is: ", d4)

# Get time

now = datetime.now()

current_time = now.strftime("%H:%M:%S")

print("Current Time is: ", current_time)

#Sample print in oneline

#sense.show_message("Temperature C" + str(temp) + "Humidity:" + str(humidity) + "Pressure:" + str(pressureMMHG), scroll_speed=(0.08), back_colour= [0,0,200])

#Defining colours

blue = (0, 0, 255)

red = (255, 0, 0)

orange = (255, 165, 0)

yellow = (255, 255, 0)

green = (0, 255, 0)

blue = (0, 0, 255)

purple = (160, 32, 240)

#Print On SenseHat Matrix // the lower the value, the faster it moves

sense.show_message ("Date: " + str(d4), scroll_speed=(0.07), text_colour=purple)

sense.show_message ("Time: " + str(current_time), scroll_speed=(0.07), text_colour=yellow)

sense.show_message("C: " + str(temp), scroll_speed=(0.10), text_colour=red)

sense.show_message("Humidity % " + str(humidity), scroll_speed=(0.10), text_colour=blue)

sense.show_message("mmHg: " + str(floatPressureMMHG), scroll_speed=(0.10), text_colour=orange)

time.sleep(1)

except KeyboardInterrupt:

pass

sense.clear()

You can just use nano myweatherstation.py and paste the above script.

You can run the script using:

sudo python myweatherstation.py

1	sudo python myweatherstation.py

To run the script in a loop, you can use:

sudo python myweatherstation.py &amp;

1	sudo python myweatherstation.py &

Enjoy!

[update from October 13th, 2023]

Following the update to Bookworm (aka Raspberry Pi OS 12), you can have the following issues:

Error:

Traceback (most recent call last):
File "/home/pi/Desktop/PY Sense Hat/pbnet-weather.py", line 2, in &lt;module&gt;
sense = SenseHat()
File "usr/lib/python3/dist-packages/sense_hat/sense_hat.py", line 39, in init
raise OSError ('Cannot detect %s device' % self.SENSE_HAT_FB_NAME)
OSError: Cannot detect RPi-Sense FB device

Traceback (most recent call last):

File "/home/pi/Desktop/PY Sense Hat/pbnet-weather.py", line 2, in <module>

sense = SenseHat()

File "usr/lib/python3/dist-packages/sense_hat/sense_hat.py", line 39, in init

raise OSError ('Cannot detect %s device' % self.SENSE_HAT_FB_NAME)

OSError: Cannot detect RPi-Sense FB device

Fix:

sudo nano /boot/config.txt

1	sudo nano /boot/config.txt

and insert the line:

dtoverlay=rpi-sense

1	dtoverlay=rpi-sense

To make the script run after reboot:

create a script called: pbnet-weather.sh and put inside: sudo python /PBNET-WEATHER/pbnet-weather.py &
make the script executable: chmod u+x pbnet-weather.sh
create a cron entry: crontab -e
in cron put: @reboot sudo /home/pi/pbnet-weather.sh &

Have fun!

[RPI/Python] Raspberry PI Weather station using SenseHat

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