IoT Experiments: Temperature Sensing

Transcript

1. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 1 Iwan Setiawan
   IoT Experiments:
   Temperature Sensing
   +Humidity
   

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2. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 2 Iwan Setiawan
   Previous Week’s Material
   ●
   Electronics refresh
   – Components
   – Tools: Fritzing
   – Prototyping
   ●
   LED switching experiments
   – Python and GPIO Zero
   – Mu editor
   ●
   Traffic lights simulation Analog
   signal
   Compute
   Storage
   Digital
   signal
   Stallings, 2016
   Communications
   

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3. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 3 Iwan Setiawan
   Objectives
   ●
   Learn how to connect DHT11 sensor to the
   Raspberry Pi
   ●
   Learn how to monitor temperature and humidity
   with the sensor through Python programs
   ●
   Learn how to store data to a CSV file and
   display to a live graph Comma-separated values
   

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4. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 4 Iwan Setiawan
   Contents
   ●
   Electronic circuit prototyping with DHT11
   ●
   Python programming using Adafruit DHT and
   matplotlib libraries
   ●
   Setting up and running experiment set 2
   – CPU temperature monitoring
   – Temperature and humidity monitoring with DHT11
   – Data collecting, storing, and live-graphing
   

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5. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 5 Iwan Setiawan
   Prototyping using Fritzing
   ●
   Download DHT11 part*
   ●
   Import the part into Fritzing
   ●
   Save and use the part for prototyping
   * https://github.com/jorgechacblogspot/librerias_fritzing
   Indicates that you need to
   take a picture of your work
   

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6. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 6 Iwan Setiawan
   Preparation
   ●
   Raspberry Pi 4 set +Ethernet cable
   ●
   Breadboard
   ●
   Jumper wires
   ●
   DHT11 sensor
   

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7. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 7 Iwan Setiawan
   Python Libraries
   ●
   Adafruit DHT, a library for DHT11/DHT22 sensor
   – Install the library using pip3
   $ sudo pip3 install Adafruit_DHT
   – Edit platform_detect.py file and add two lines in pi_version function
   $ sudo nano /usr/local/lib/python3.7/dist-packages/Adafruit_DHT/platform_detect.py
   …
   elif match.group(1) == ‘BCM2711’:
   return 3
   ...
   ●
   Matplotlib, a visualizations library, included in Raspberry Pi OS
   * https://github.com/adafruit/Adafruit_Python_DHT
   Notes: Add consistent when editing
   

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8. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 8 Iwan Setiawan
   CPU Temperature: Monitoring
   ●
   Run Mu editor
   ●
   Type the code, save, and run
   from gpiozero import CPUTemperature
   from time import sleep
   cpu = CPUTemperature()
   while True:
   temp = cpu.temperature
   print(temp)
   sleep(1)
   cpu_temp.py
   * https://gpiozero.readthedocs.io/en/stable/api_internal.html#cputemperature
   

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9. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 9 Iwan Setiawan
   CPU Temperature: Storing Data
   ●
   Type the code, save, and run
   from gpiozero import CPUTemperature
   from time import sleep, strftime, time
   cpu = CPUTemperature()
   with open(“/home/pi/acnt/cpu_temp.csv”, ”a”) as log:
   while True:
   temp = cpu.temperature
   log.write(“{0},{1}\n”.format(strftime(“%Y-%m-%d %H:%M:%S”),str(temp)))
   sleep(1)
   cpu_temp-csv.py
   

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10. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 10 Iwan Setiawan
    CPU Temperature: Live-graphing
    ●
    Type the code, save,
    and run
    ●
    After the live graph is
    shown, execute a
    program, e.g.
    Chromium
    ●
    Observe the graph
    from gpiozero import CPUTemperature
    from time import time
    import matplotlib.pyplot as plt
    cpu = CPUTemperature()
    plt.ion() # enable interactive mode
    x = [] # create dict x
    y = [] # create dict y
    while True:
    temp = cpu.temperature # get temp
    y.append(temp) # append temp to dict y
    x.append(time()) # append time to dict x
    plt.clf() # clear figure
    plt.scatter(x,y) # scatter plot for x and y
    plt.plot(x,y) # plot
    plt.pause(0.05) # pause
    plt.draw() # update figure cpu_temp-plot.py
    

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11. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 11 Iwan Setiawan
    Raspberry Pi Foundation, CC By-SA 4.0
    

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12. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 12 Iwan Setiawan
    DHT11 Prototyping
    +
    

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13. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 13 Iwan Setiawan
    Temp. and Humid. Monitoring
    ●
    Type the code, save, and run
    import Adafruit_DHT
    sensor = Adafruit_DHT.DHT11
    pin = 21
    while True:
    try:
    humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)
    if humidity is not None and temperature is not None:
    print(“Temperature: {0:0.1f}*C Humidity: {1:0.1f}%.format(temperature, humidity))
    else:
    print(“Cannot pull data from the sensor”)
    except KeyboardInterrupt:
    exit()
    temp_humi.py
    

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14. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 14 Iwan Setiawan
    IoT Assignment 3
    1. Find the basic principles of DHT11
    – Temperature sensing
    – Humidity sensing
    2. CPU temperature monitoring
    – Merge storing data and live-graphing codes to one code
    – Use Python functions
    – Add control flow: if the temperature is high, show an alert
    message
    

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15. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 15 Iwan Setiawan
    IoT Assignment 3
    3. Simple smart home application: implementing two features
    – Storing and displaying the temperature data collected through DHT11
    ●
    Store the data to a CSV file
    ●
    Display the data to a live graph
    – Indicators for temperature rising
    ●
    Add a red LED and buzzer representing indicators
    ●
    Control flow: If the temperature changes between 30 to 35 degree Celcius, the
    buzzer sounds long beep. If it is above 35 degree Celcius, the buzzer produces
    short beep plus the red LED turns on and a message shows up informing high
    temperature or heat alert. Simulate this situation with a demo
    ●
    Question: Can we use DHT11 to detect fire? If yes, how would you use it to detect
    the event? If no, why?
    

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16. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 16 Iwan Setiawan
    Results to be Uploaded
    1. Experiment results: photos and explanations
    2. Assignment 3 results
    – Fritzing export image using Breadboard view
    – Photos and a demo video showing the results
    – Source code, screenshots/figures, and explanations
    Upload your experiment and assignment 3 results to Moodle
    ●
    Using one PDF file
    ●
    One group, one document
    ●
    Upload your demo video somewhere, only attach the URL to the doc.
    06/10
    9pm
    code
    experiment
    

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17. Advanced Computer Networks Tutorials, Spring 2021, CSIE NTUST 17 Iwan Setiawan
    Resources
    ●
    Raspberry Pi Foundation, “Temperature log,” 2021.
    [Online]. Available: https://projects.raspberrypi.org/en/-
    projects/temperature-log
    ●
    Stack Overflow, “cannot import name 'Beaglebone_-
    Black_Driver' from 'Adafruit_DHT',” 2020. [Online].
    Available: https://stackoverflow.com/questions/-
    63232072/cannot-import-name-beaglebone-black-
    driver-from-adafruit-dht
    

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