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Introduction to Raspberry Pi

Artisan's Asylum

Home Automation Case Study


  • Need Flask installed
  • Need Flask Bootstrap module installed
    • Bootstrap is a piece of software from Twitter that makes it easy to create slick looking websites with little effort.
sudo pip install flask-bootstrap
  • Need RPi.GPIO installed
  • Get the class source code, by doing ONE of the following options:
    • On your Raspberry Pi type git clone
    • In the Adafruit WebIDE, clone the above repository
    • Download Zip file by running wget then unzip
  • Be sure to build the circuit on your board before testing the code that uses those pins

Running the webserver

  $ cd FlaskGpioTest
  FlaskGpioTest$ sudo ./
   * Running on
   * Restarting with reloader

Flask Practice

  1. Point your computer's web browser at http://piname.local:5000/. You should see a webpage with a "Test" button on it.
  2. Clicking the "Test" button will make a request to "/test". If you click the button, it should fail with a 404 error, because no handler exists for the "/test" path
  3. Open another ssh connection and use nano to edit the file. Add a handler for "/test" that will display a successful message to the user. You can display a message by setting the "successMsg" parameter in the call to render_template()
  4. Clicking the button should now display a success message in the browser

Click to turn lamp on/off

Use the "Lighting" tab on the left for this section.

  1. Before we can use the RPi.GPIO library, you must import it first. This should happen at the top of the source file
  2. Next, call RPi.GPIO.setmode() to use the board in Broadcom (BCM) mode. This will match the numbers on your breakout board. This should be done as part of the server setup, but before starting the server
  3. Call RPi.GPIO.setup(pin#, GPIO.OUT) to set the lamp pin (#18) as an output. This should be done immediately after the code for step #2
  4. As part of the request handler for clicking the "On" and "Off" buttons, use RPi.GPIO.output(pin#, GPIO.HIGH/GPIO.LOW) to turn the LED on or off
def lighting_on():
  """Turn the lamp on by setting LAMP_PIN to high. """
  lightingData['active'] = True
  return render_template('flaskGpioTemplate.html', page_title="Lighting", lighting=lightingData) 

Set schedule to turn the coffee maker on/off

  1. Before using any timer, you must import the threading library
  2. To run a timer, create a timer object containing the remaining time and function to run when the timer expires.
  3. Call timer.start()
  4. To stop the timer, call timer.stop()
  5. You should set the timer in coffeeset() and cancel the timer in coffeestop()
import threading

def expired():
  print "Timer Expired"

t = threading.Timer(30, expired) #30 seconds

# To cancel:

Check if dryer still running

  1. Set the dryer pin as an input pin in the setup function.
  2. In appliances(), read the state of the input pin.
  3. Put the state of the pin in applianceData['dryer']
  4. You may want to add this code to coffee_set() and coffee_stop() as well

Check if doorbell rung since last check

  1. Set the doorbell pin as an input pin in the setup function
  2. Call add_event_detect() for the doorbell_pin
  3. In the exterior() function, call event_detected() on the doorbell_pin.
  4. If the doorbell has been pushed, set exterior['doorbell'] to False

Track the time the mailman shows up

  1. Write a callback function (mailboxCallback()) that will record the current time into lastMailboxPush
  2. Set the mailbox pin as an input pin in the setup function
  3. Call add_event_detect() for the mailbox pin and provide the name of the callback from step 1

Solution Source Code