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Practical Python Programming for IoT

You're reading from   Practical Python Programming for IoT Build advanced IoT projects using a Raspberry Pi 4, MQTT, RESTful APIs, WebSockets, and Python 3

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Product type Paperback
Published in Nov 2020
Publisher Packt
ISBN-13 9781838982461
Length 516 pages
Edition 1st Edition
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Author (1):
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Gary Smart Gary Smart
Author Profile Icon Gary Smart
Gary Smart
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Toc

Table of Contents (20) Chapters Close

Preface 1. Section 1: Programming with Python and the Raspberry Pi
2. Setting Up your Development Environment FREE CHAPTER 3. Getting Started with Python and IoT 4. Networking with RESTful APIs and Web Sockets Using Flask 5. Networking with MQTT, Python, and the Mosquitto MQTT Broker 6. Section 2: Practical Electronics for Interacting with the Physical World
7. Connecting Your Raspberry Pi to the Physical World 8. Electronics 101 for the Software Engineer 9. Section 3: IoT Playground - Practical Examples to Interact with the Physical World
10. Turning Things On and Off 11. Lights, Indicators, and Displaying Information 12. Measuring Temperature, Humidity, and Light Levels 13. Movement with Servos, Motors, and Steppers 14. Measuring Distance and Detecting Movement 15. Advanced IoT Programming Concepts - Threads, AsyncIO, and Event Loops 16. IoT Visualization and Automation Platforms 17. Tying It All Together - An IoT Christmas Tree 18. Assessments 19. Other Books You May Enjoy

Connecting to the broker

We define our onConnectionSuccess() handler at line (5), which will be called after our client successfully connects to the broker. When we successfully connect, we then update the web page to reflect the successful connection and enable the slider control:

onConnectionSuccess = function(data) {         // (5)
console.log("Connected to MQTT Broker");
$("#connected").html("Yes");
$("input[type=range].brightnessLevel")
.attr("disabled", null);

client.subscribe(TOPIC); // (6)
};

client.connect({ // (7)
onSuccess: onConnectionSuccess,
reconnect: true
});

Next, at line (6), we subscribe to the led topic. It's at line (7) that we connect to the broker. Notice that we're registering the onConnectionSuccess function as the onSuccess option.

Remember, similar to the Python example, always subscribe to...
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