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Diff for: README.md

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-# Practical-Python-Programming-for-IoT
-Practical Python Programming for IoT, published by Packt
+# Practical Python Programming for IoT
+
+The code in this repository accompanies the Packt Book Practical Python Programming for IoT, published by Packt.
+
+## [Chapter 1](chapter01) - Setting Up Your Development Environment
+
+## [Chapter 2](chapter02) - Introduction to Python and IoT
+
+## [Chapter 3](chapter03) - RESTFul APIs and Web Socket Services with Flask
+
+## [Chapter 4](chapter04) - Distributed Systems with Python and MQTT
+
+## [Chapter 5](chapter05) - Connecting Your Raspberry Pi to the Physical World
+
+## [Chapter 6](chapter06) - Electronics 101 for the Software Engineer
+
+## [Chapter 7](chapter07) - Switching Things On and Off
+
+## [Chapter 8](chapter08) - Lights, Indicators and Displaying Information
+
+## [Chapter 9](chapter09) - Measuring Temperature, Humidity and Moisture
+
+## [Chapter 10](chapter10) - Movement with Motors, Servos and Steppers
+
+## [Chapter 11](chapter11) - Measuring Distance and Detecting Movement
+
+## [Chapter 12](chapter12) - Advanced IoT Programming Concepts - Event-Loops, Threads, PubSub & AsyncIO
+
+## [Chapter 13](chapter13) - IoT and Automation Platforms
+
+## [Chapter 14](chapter14) - Tying it Altogether - An IoT Christmas Tree
+

Diff for: chapter01/README.md

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+# Practical Python Programming for IoT
+
+## Chapter 1 - Setting Up Your Development Environment
+
+* `requirements.txt` - Python dependencies required for this chapter
+
+* `gpio_pkg_check.py` - Verify availability of Python GPIO Libraries 
+
+* `run_on_boot.sh` - Bash helper script to start a Python program on boot 

Diff for: chapter01/gpio_pkg_check.py

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+"""
+File: chapter01/gpio_pkg_check.py
+
+This Python script checks for the availability of various Python GPIO Library Packages for the Raspberry Pi.
+It does this by attempting to import the Python package. If the package import is successful
+we report the package as Available, and if the import (or import initialization) fails for any reason,
+we report the package as Unavailable.
+
+Dependencies:
+  pip3 install gpiozero pigpio
+
+Built and tested with Python 3.7 on Raspberry Pi 4 Model B
+"""
+try:
+    import gpiozero
+    print('GPIOZero   Available')
+except:
+    print('GPIOZero   Unavailable. Install with "pip install gpiozero"')
+
+try:
+    import pigpio
+    print('PiGPIO     Available')
+except:
+    print('PiGPIO     Unavailable. Install with "pip install pigpio"')
+

Diff for: chapter01/requirements.txt

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+colorzero==1.1
+gpiozero==1.5.1
+pigpio==1.44

Diff for: chapter01/run_on_boot.sh

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+#!/bin/bash
+#File: chapter01/run_on_boot.sh
+
+# Absolute path to Virtual Environment python interpreter
+PYTHON=/home/pi/pyiot/chapter01/venv/bin/python
+
+# Absolute path to Python script
+SCRIPT=/home/pi/pyiot/chapter01/gpio_pkg_check.py
+
+# Absolute path to output log file
+LOG=/home/pi/pyiot/chapter01/gpio_pkg_check.log
+
+echo -e "\n####### STARTUP $(date) ######\n" >> $LOG
+
+$PYTHON $SCRIPT >> $LOG 2>&1

Diff for: chapter02/README.md

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+# Practical Python Programming for IoT
+
+## Chapter 2 - Introduction to Python and IoT
+
+* `requirements.txt` - Python dependencies required for this chapter
+
+* `led_gpiozero.py` - Flashing a LED using GPIOZero
+
+* `led_pigpio.py` - Flashing a LED using PiGPIO
+
+* `button_gpiozero.py` - Responding to a button using GPIOZero
+
+* `button_pigpio.py` - Responding to a button using PiGPIO
+
+* `dweet_led.py` - Controlling a LED over the Internet using dweet.io
+
+* `dweet_button.py` - Creating a dweet using a push button
+
+* `pigpio_led_class.py` - PiGPIO class wrapper example

Diff for: chapter02/button_gpiozero.py

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+"""
+File: chapter02/button_gpiozero.py
+
+Turn on and off an LED with a Button using GPIOZero.
+
+Dependencies:
+  pip3 install gpiozero pigpio
+
+Built and tested with Python 3.7 on Raspberry Pi 4 Model B
+"""
+from gpiozero import Device, LED, Button                                        # (1)
+from gpiozero.pins.pigpio import PiGPIOFactory
+import signal                                                                   # (2)
+
+LED_GPIO_PIN = 21
+BUTTON_GPIO_PIN = 23
+
+Device.pin_factory = PiGPIOFactory() #set gpiozero to use pigpio by default.
+
+def pressed():
+    led.toggle()                                                                # (3)
+    state = 'on' if led.value == 1 else 'off'                                   # (4)
+    print("Button pressed: LED is " + state)                                    # (5)
+
+led = LED(LED_GPIO_PIN)
+led.off()
+
+button = Button(BUTTON_GPIO_PIN, pull_up=True, bounce_time=0.1)                 # (6)
+button.when_pressed = pressed                                                   # (7)
+
+print("Press button to turn LED on and off.")
+
+signal.pause() # Stops program from exiting.                                    # (8)

Diff for: chapter02/button_pigpio.py

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+"""
+File: chapter02/button_gpiozero.py
+
+Turn on and off an LED with a Button using PiGPIO.
+
+Dependencies:
+  pip3 install pigpio
+
+Built and tested with Python 3.7 on Raspberry Pi 4 Model B
+"""
+import pigpio
+import signal
+
+LED_GPIO_PIN = 21
+BUTTON_GPIO_PIN = 23
+
+pi = pigpio.pi()
+
+
+# LED provides 'Output'
+pi.set_mode(LED_GPIO_PIN, pigpio.OUTPUT)
+pi.write(LED_GPIO_PIN, 0) # LED Off
+
+
+# Button provides 'Input'
+pi.set_mode(BUTTON_GPIO_PIN, pigpio.INPUT)                                    # (1)
+pi.set_pull_up_down(BUTTON_GPIO_PIN, pigpio.PUD_UP)                           # (2)
+pi.set_glitch_filter(BUTTON_GPIO_PIN, 10000) # microseconds debounce          # (3)
+
+
+# Button pressed handler
+def pressed(gpio_pin, level, tick):                                           # (4)
+    # Get current pin state for LED.
+    led_state = pi.read(LED_GPIO_PIN)                                         # (5)
+
+    if led_state == 1:                                                        # (6)
+        # LED is on, so turn it off.
+        pi.write(LED_GPIO_PIN, 0) # 0 = Pin Low = Led Off
+        print("Button pressed: Led is off")
+    else: # 0
+        # LED is off, so turn it on.
+        pi.write(LED_GPIO_PIN, 1) # 1 = Pin High = Led On
+        print("Button pressed: Led is on")
+
+
+# Register button handler.
+pi.callback(BUTTON_GPIO_PIN, pigpio.FALLING_EDGE, pressed)                    # (7)
+
+print("Press button to turn LED on and off.")
+
+signal.pause() # Stops program from exiting.

Diff for: chapter02/dweet_button.py

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+"""
+File: chapter02/dweet_button.py
+
+A Python program to control an LED using the public dweet.io service
+by using a Button to post a dweet.
+
+Dependencies:
+  pip3 install gpiozero pigpio requests
+
+Built and tested with Python 3.7 on Raspberry Pi 4 Model B
+"""
+import signal
+import requests
+import logging
+from gpiozero import Device, Button
+from gpiozero.pins.pigpio import PiGPIOFactory
+
+# Initialize Logging
+logging.basicConfig(level=logging.WARNING)
+logger = logging.getLogger('main')
+logger.setLevel(logging.INFO)
+
+# Initialise GPIOZero
+Device.pin_factory = PiGPIOFactory()
+
+BUTTON_GPIO_PIN = 23
+button = None
+LED_STATES = ['off', 'on', 'blink']
+current_led_state = 0 # off
+
+# Make sure thing_name matches the "dweet_led thing" you want to control.
+thing_name = '**** ADD YOUR THING NAME HERE ****'
+URL = 'https://dweet.io'
+
+
+def init_button():
+    """Setup button"""
+    global button
+    button = Button(BUTTON_GPIO_PIN, pull_up=True, bounce_time=0.1)
+    button.when_pressed = button_pressed
+
+
+def button_pressed():
+    """Button pressed handler"""
+    cycle_led_state()
+
+
+def cycle_led_state():
+    """Send revolving dweet to change LED from off -> on -> blink -> off -> ..."""
+    global current_led_state
+    current_led_state += 1
+
+    if current_led_state >= len(LED_STATES):
+        current_led_state = 0
+
+    state = LED_STATES[current_led_state]
+
+    logger.info('Setting LED state %s', state)
+    send_dweet(thing_name, {'state': state})
+
+
+def send_dweet(thing_name, values):
+    """Send a dweet to a thing."""
+
+    resource = URL + '/dweet/for/' + thing_name
+    logger.debug('Dweeting to url %s with values %s', resource, values)
+
+    r = requests.get(resource, params=values)
+
+    if r.status_code == 200:
+        dweet_response = r.json()
+        logger.debug('Dweet response was %s', dweet_response)
+        return dweet_response
+
+    else:
+        logger.error('Dweeting dweet failed with http status %s', r.status_code)
+        return {}
+
+
+# Initialise Module
+init_button()
+
+
+# Main entry point
+if __name__ == '__main__':
+    # You could adopt the get_last_dweet() / process_dweet() from dweet_listner.py
+    # to initialise the led state in this file. For simplicity we're just
+    # starting with 'Off' (current_led_state = 0)
+
+    print("Press button to send a dweet to turn LED on, blink or off.")
+
+    # Stop Python from exiting.
+    signal.pause()