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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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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

Powering the APA102 circuit

In Chapter 7, Turning Things On and Off, we discussed the importance of knowing the current requirements of a "load" that you are using. Let's apply that learning to our APA102 LED strip so we can power it correctly. Our example is assuming a LED strip containing 60 LEDs, however, you will need to adjust the calculations based on the number of LEDs on your strip.

By the way of example, we have the following:

  • An APA102 LED strip with 60 LEDs.
  • Each LED uses (on average) a maximum of 25mA (from the datasheet and confirmed by measurement).
  • The LED strip consumes approximately 15mA when idle (no LED is lit).
A single RGB LED uses its maximum current when it is set to the color white, which is when each individual LED (red, green, and blue) are at their full brightness.

Using the preceding values, we can calculate our expected maximum current requirement for 60 LEDs, which is just over 1.5 amps:

If we work in the assumption that we are using...

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