Temperature Value Shown on LEDs

[n1ck75]

Code totally lifted from Johnny5C, updated sensehat parts.

was wondering if you could get the output to flash up (fade in) every x seconds to just show temp?

Code: Select all

#!/usr/bin/python
from sense_hat import SenseHat
import time

ap = SenseHat()
temp = ap.get_temperature()
humidity = ap.get_humidity()
pressure = ap.get_pressure()


print("Temp: %s C" % temp)               # Show temp on console
print("Humidity: %s %%rH" % humidity)        # Show humidity on console
print("Pressure: %s Millibars" % pressure)    # Show pressure on console

ap.set_rotation(180)        # Set LED matrix to scroll from right to left
              
ap.show_message("%.1f C" % temp, scroll_speed=0.10, text_colour=[0, 255, 0])

time.sleep(1)           # Wait 1 second

ap.show_message("%.1f %%rH" % humidity, scroll_speed=0.10, text_colour=[255, 0, 0]) 

time.sleep(1)      # Wait 1 second

ap.show_message("%.1f Millibars" % humidity, scroll_speed=0.10, text_colour=[0, 0, 255])

ap.clear()      # Clear LED matrix

[scotty101]

Yes of course. You need to wrap the parts of the code that you wish to repeat inside a loop. If you want this to happen indefinitely then use a while loop.

For example

Code: Select all

while True:
    ap.show_message("Hello again")
    time.sleep(10)

This will print Hello Again every 10 seconds until you kill the program.

[dliloch]

I think you want the last message to use the pressure variable? also the temp on my sensehat seems about 15% high in relation to the ambient temp .. so I just took 85% of it .. I wonder if there is a better way to get ambient temp.. I imagine the leds and the processor throw the temp sensor off ..
the pressure and relative humidity seem accurate ..
nice example to work with .. thanks..

[n1ck75]

Updated to just show the temperature continuously (Thx Scotty101)

Code: Select all

#!/usr/bin/python
from sense_hat import SenseHat
import time
while True:
    ap = SenseHat()
    temp = ap.get_temperature()
    print("Temp: %s C" % temp)               # Show temp on console

    ap.set_rotation(180)        # Set LED matrix to scroll from right to left

    ap.show_message("%.1f C" % temp, scroll_speed=0.10, text_colour=[0, 255, 0])
    time.sleep(10)

Next question, is it possible to adjust the temp output by a percentage, to adjust for the latent temp of pi/led. ie.

output / 5%

[subjektivdk]

Updated to just show the temperature continuously (Thx Scotty101)

Code: Select all

#!/usr/bin/python
from sense_hat import SenseHat
import time
while True:
    ap = SenseHat()
    temp = ap.get_temperature()
    print("Temp: %s C" % temp)               # Show temp on console

    ap.set_rotation(180)        # Set LED matrix to scroll from right to left

    ap.show_message("%.1f C" % temp, scroll_speed=0.10, text_colour=[0, 255, 0])
    time.sleep(10)

Next question, is it possible to adjust the temp output by a percentage, to adjust for the latent temp of pi/led. ie.

output / 5%

output * 0.95

[AndersM]

Also see this thread on temperature sensors and ambient temperature.

[hansonm]

is there a way to convert the temp to Fahrenheit?

[scotty101]

Yes of course. It's quite a simple conversion from Celsius to Fahrenheit.
http://www.pythonforbeginners.com/code- ... converter/

[DougieLawson]

is there a way to convert the temp to Fahrenheit?

Code: Select all

temp = ((temp/5)*9)+32 

[n1ck75]

How could you show colour variant to indicate temperature?

Example;

Above 16C = Red
Below 16C = Blue

[AndersM]

Made Python program that displays a temperature scale from violet to red using a "trick" with HLS hue to easily create the colours in the scale.

Code: Select all

import time
import colorsys
from sense_hat import SenseHat

sense = SenseHat()

#The limits of the temperature scale
MAXTEMP = 40.0
MINTEMP = 0.0
#The limits of the HLS hue scale 0.0=red, 0.9=violet 
MAXHUE = 0.0
MINHUE = 0.90

while 1:
    # reading temp and correcting for sensor bias
    temp = sense.get_temperature()
    calctemp = 0.0071*temp*temp+0.857*temp-10.0 

    #Calculating hue from temp and limit to scale range
    hue = MINHUE-(calctemp-MINTEMP)/(MAXTEMP-MINTEMP)*(MINHUE-MAXHUE)
    hue = min(hue,MINHUE)
    hue = max(hue,MAXHUE)
    
    #translating HLS to RGB and displaying with LEDs
    rgbfloat=colorsys.hls_to_rgb(hue, 0.5, 1)
    rgb=(int(rgbfloat[0]*255), int(rgbfloat[1]*255), int(rgbfloat[2]*255))
    sense.clear(rgb)

    #Debug stuff
    #print calctemp
    #print hue
    
    time.sleep(1)

[tonygo2]

Here is a different way to show temperatures or humidity. The latter works better in a demo as it is easier to get the values to change quite quickly over a greater range if you 'huff' on it and then let it return to normal.

Please remember that these sensors are not very accurate - ignore the decimal part it is total fiction - round to the nearest integer.

Code: Select all

# Humidity/Temperature display for Sense Hat - Demo
# Tony Goodhew 27 September 2015
# Python3 - "Use sudo idle3"
from sense_hat import SenseHat
import time

sense = SenseHat()
sense.clear()

#one row per 5x3 digit - 0 to 9
nums =[1,1,1,1,0,1,1,0,1,1,0,1,1,1,1,  # 0
       0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,  # 1
       1,1,1,0,0,1,0,1,0,1,0,0,1,1,1,  # 2
       1,1,1,0,0,1,1,1,1,0,0,1,1,1,1,  # 3
       1,0,0,1,0,1,1,1,1,0,0,1,0,0,1,  # 4
       1,1,1,1,0,0,1,1,1,0,0,1,1,1,1,  # 5
       1,1,1,1,0,0,1,1,1,1,0,1,1,1,1,  # 6
       1,1,1,0,0,1,0,1,0,1,0,0,1,0,0,  # 7
       1,1,1,1,0,1,1,1,1,1,0,1,1,1,1,  # 8
       1,1,1,1,0,1,1,1,1,0,0,1,0,0,1]  # 9

def show_num(val,xd,yd,r,g,b):
    offset = val * 15
    for p in range(offset,offset + 15):
        if nums[p] == 1:
            xt = p % 3
            yt = (p-offset) // 3
            sense.set_pixel(xt+xd,yt+yd,r,g,b)       
    
def show_number(val,r,g,b): # Range -100 to 100
    abs_val = abs(val)
    tens = abs_val // 10
    units = abs_val % 10
    sense.clear()
    if (abs_val > 9): show_num(tens,0,2,r,g,b)
    show_num(units,4,2,r,g,b)
    if abs_val == 100: # Deal with 3 digit "100"
        sense.clear()
        show_num(0,5,2,r,g,b)
        show_num(0,2,2,r,g,b)
        for i in range(2,7):
            sense.set_pixel(0,i,r,g,b)
    if val < 0 :       # Display 'Negative' bar
        for i in range(0,8):
            sense.set_pixel(i,0,0,0,128)

#========== MAIN ===============

print("===== Constantly display Humidity =====")
print("**  Tony Goodhew -- 27 Sept 2015  **\n")
print("         Terminate with CTRL-C")
print(" Huff on humidity sensor to change value")

old_val = -999 # Out of range, changed first time
while True:
    val = sense.get_humidity() # Only accurate to +/- 0.5 %
#    val = sense.get_temperature_from_humidity()
#    val = sense.get_temperature_from_pressure()
    sign = 1 # Useful for low temperatures
    if val < 0 :
        sign = -1
    val = int(abs(val + 0.5)) # round to nearest whole deg C
    if val != old_val: # Has humidity changed?
        old_val = val
        sense.clear()
        show_number(val,128,50,30)
        time.sleep(0.3)

Comments/ suggestions welcome

[anthonyw40]

I have been working on the some modified code for making a thermostat, and it all works until I try to get the newtemp going either + or -. the sense hat joystick will not function to the left right up or down correctly. However, it does work when pushed down. I am new a coding in Python so any help would be much appreciated. Once I get this running, then I will create the lines of code to measure the difference of newtemp and var to determine if the GPIO pin should be pulled high or not.

# Temperature display for Sense Hat
# Orignial code by Tony Goodhew 27 September 2015
# Python3 - "Use sudo idle3"
from sense_hat import SenseHat
import time

sense = SenseHat()
sense.clear()

#one row per 5x3 digit - 0 to 9
nums =[1,1,1,1,0,1,1,0,1,1,0,1,1,1,1, # Number 0
0,1,0,0,1,0,0,1,0,0,1,0,0,1,0, # Number 1
1,1,1,0,0,1,0,1,0,1,0,0,1,1,1, # Number 2
1,1,1,0,0,1,1,1,1,0,0,1,1,1,1, # Number 3
1,0,0,1,0,1,1,1,1,0,0,1,0,0,1, # Number 4
1,1,1,1,0,0,1,1,1,0,0,1,1,1,1, # Number 5
1,1,1,1,0,0,1,1,1,1,0,1,1,1,1, # Number 6
1,1,1,0,0,1,0,1,0,1,0,0,1,0,0, # Number 7
1,1,1,1,0,1,1,1,1,1,0,1,1,1,1, # Number 8
1,1,1,1,0,1,1,1,1,0,0,1,0,0,1] # Number 9

def show_num(val,xd,yd,r,g,b):
offset = val * 15
for p in range(offset,offset + 15):
if nums[p] == 1:
xt = p % 3
yt = (p-offset) // 3
sense.set_pixel(xt+xd,yt+yd,r,g,b)

def show_number(val,r,g,b): # Range -100 to 100
abs_val = abs(val)
tens = abs_val // 10
units = abs_val % 10
sense.clear()
if (abs_val > 9): show_num(tens,0,2,r,g,b)
show_num(units,4,2,r,g,b)
if abs_val == 100: # Deal with 3 digit number "100"
sense.clear()
show_num(0,5,2,r,g,b)
show_num(0,2,2,r,g,b)
for i in range(2,7):
sense.set_pixel(0,i,r,g,b)
if val < 0 : # Display 'Negative' bar
for i in range(0,8):
sense.set_pixel(i,0,0,0,128)

#========== MAIN ===============

print("Displays Temperature in Farenheight on 8x8 Matrix")
print("Anthony White - 2018, March 11")
print("Terminate program by pressing CTRL-C")

red = (255,0,0) # Setting color
green = (0,255,0 )# Setting color
white = (150, 150, 150) # Setting color
old_val = -999 # Out of range, first time through
while True:
temp = sense.get_temperature_from_humidity() # Gets temp from sensor
calctemp = 0.0071*temp*temp+0.857*temp-10.0 # Known temp correction for heat generated from ARM
val = ((calctemp/5)*9)+27 # conversion from Celcuius to Farenheight accounted for further temp deviaton that was found
sign = 1 # Used for low temperatures
if val < 0 :
sign = -1
val = int(abs(val + 0.5)) # round to nearest whole deg
if val != old_val: # Has temperature changed?
old_val = val
sense.clear()
show_number(val,50,50,255)
sense.set_pixel(0,0,red) # link indicator
sense.set_pixel(7,0,white) # creates degrees symbol
sense.set_pixel(6,0,white)
sense.set_pixel(7,1,white)
sense.set_pixel(6,1,white)
sense.set_rotation(270)
while True:
for event in sense.stick.get_events():
if event.action == "pressed":
if event.direction == "middle":
show_number(val,50,50,255)
sense.set_pixel(0,0,green) # link indicator
sense.set_pixel(7,0,white) # creates degrees symbol
sense.set_pixel(6,0,white)
sense.set_pixel(7,1,white)
sense.set_pixel(6,1,white)
sense.set_rotation(270)
elif event.direction == "right": #goes into a set temp mode
sense.clear()
show_number(val,50,50,255)
sense.set_pixel(7,0,white) # creates degrees symbol
sense.set_pixel(6,0,white)
sense.set_pixel(7,1,white)
sense.set_pixel(6,1,white)
sense.set_rotation(270)
while True:
if event.direction == "up": #set temp up
newtemp = val + 1
sense.clear()
show_number(newtemp,0,255,0)
sense.set_pixel(7,0,white) # creates degrees symbol
sense.set_pixel(6,0,white)
sense.set_pixel(7,1,white)
sense.set_pixel(6,1,white)
sense.set_rotation(270)
elif event.direction == "down": # set temp down
newtemp = val - 1
sense.clear()
show_number(newtemp,0,255,0)
sense.set_pixel(7,0,white) # creates degrees symbol
sense.set_pixel(6,0,white)
sense.set_pixel(7,1,white)
sense.set_pixel(6,1,white)
sense.set_rotation(270)
elif event.direction == "left": # go out of set temp routine
show_number(val,50,50,255)
sense.set_pixel(0,0,green) # link indicator
sense.set_pixel(7,0,white) # creates degrees symbol
sense.set_pixel(6,0,white)
sense.set_pixel(7,1,white)
sense.set_pixel(6,1,white)
sense.set_rotation(270)
sleep(0.5) # Wait a while and then clear the screen
sense.clear()

time.sleep(2) #Wait time before next sample and display

[tonygo2]

This is how I got the SenseHAT joystick working. I hope this helps

Code: Select all

# Modified from Astro Pi Guide for Teachers
#      raspberrypi.org/resources
# Tony Goodhew 26 Sept 2015
import pygame

from pygame.locals import *
from sense_hat import SenseHat

pygame.init()
pygame.display.set_mode((90,5))#Big enough

sense = SenseHat()
sense.clear()

print("Steer the BLOB with the joystick")
print("  * Up, Down, Left or Right *\n")
print("Quit with Joystick Centre Button, RETURN or ESC\n")

running = True

x = 0
y = 0
sense.set_pixel(x, y, 255, 255, 255)

while running:
    for event in pygame.event.get():
        if event.type == KEYDOWN:
            sense.set_pixel(x, y, 0, 0, 0)  # Black 0,0,0 means OFF

            if event.key == pygame.K_DOWN and y < 7:
                y = y + 1
            elif event.key == pygame.K_UP and y > 0:
                y = y - 1
            elif event.key == pygame.K_RIGHT and x < 7:
                x = x + 1
            elif event.key == pygame.K_LEFT and x > 0:
                x = x - 1
            elif event.key == pygame.K_RETURN:
                running = False
                sense.clear()
                print("** BYE from Joystick **")
            if running: sense.set_pixel(x, y, 255, 255, 255)
            
        if event.type == QUIT:
            running = False
            sense.clear()
            print(" ++ BYE from mouse QUIT ++")
            

[tonygo2]

Getting code to display correctly in a post.

Paste the code into the editor. Make space above and below. Select the code and then click on "Code" in the menu.

Hope this also helps

[alphanumeric]

This what I did with my sense hat. The color for each element, temp, humidity, pressure etc changes depending on the value. Red text for temp if its very hot. Blue for temp if its below zero etc. I use the joystick to adjust the brightness of the display, or change the text to all white. A center push shuts down the Pi. I have a second portable setup that uses a BMP180 for the temp, its mounted on the exterior of the case. I also have a SI1145 light sensor that auto adjusts the LED matrix. Low light if its in the shade or darkness. It's easier on the eyes. Full bright in a lit area, and all white text in bright sunlight. I find Red and Blue text hard to see read in very bright sunlight. This Pi goes with me to our dog park to keep an eye on conditions. The SI1145 also gives me the UV index. The joystick on the portable can override the auto adjustment of the LED matrix. Bothe of these Pi's / Sense hats are flipped 180 degrees. I did this so the GPIO is on the bottom and the space above is open so hot air can escape. I have a Proto Hat with a RTC on it between the Pi and Sense hat. Temps read Ok on the one I have in the house, it doesn't have a case on it. The portable one read high though so I added the BMP180 externally to get accurate temp readings. I just posted the simpler code for the one that just sits in our living room.

Code: Select all

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 <= 27:
        tc = [w, 255, w]  # green
    elif t > 27:
        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 > 100:
        h = 100

    if 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)
    else:
        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 >= 960 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 Percipitationb" % (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:
        os.system("sudo shutdown now -P")
    elif x == 1:
        raise SystemExit

# Last edited on March 14th 2018
# run sudo crontab -e
# add
# @reboot python3 /home/pi/THP.py &

[Bbuschke]

is this just on a led light or displaying the number on some sort of led display?

[alphanumeric]

In my above code the temperature is displayed as a numerical value on the sense hats LED matrix. Its a scrolling message. The color of the text also changes depending on the value. If the temperature is for example 0c or lower, the text is Blue. Above 0c but below 13c its Yellow, 13c and above its Green, 27c and above its Red. Same thing is done for Humidity and Pressure, the color of that text changes based on conditions.
The message goes as follows.
It is Thursday May 31 5:51:AM and 4c with 59% Humidity - Barometric Pressure is Mid range @ 1018mb

I have another similar setup where I also turn on a 10mm LED as a secondary quick glance indicator. I didn't post that code, went with the simpler version.

[eza]

I wrote a small library that can help with displaying things on the Sense HAT's display.

You can call its functions from your own Python code or from a shell script.

It's hosted on Github - https://github.com/e2m4n/python-sense-hat-display-utils - and you can install it with "pip install sense-hat-display-utils".

[alphanumeric]

Just realized I already posted this, I think I may need another cup of coffee.