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Mastering Internet of Things

You're reading from   Mastering Internet of Things Design and create your own IoT applications using Raspberry Pi 3

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Product type Paperback
Published in Mar 2018
Publisher Packt
ISBN-13 9781788397483
Length 410 pages
Edition 1st Edition
Concepts
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Author (1):
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Peter Waher Peter Waher
Author Profile Icon Peter Waher
Peter Waher
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Toc

Table of Contents (18) Chapters Close

Preface 1. Preparing Our First Raspberry Pi Project FREE CHAPTER 2. Creating a Sensor to Measure Ambient Light 3. Creating an Actuator for Controlling Illumination 4. Publishing Information Using MQTT 5. Publishing Data Using HTTP 6. Creating Web Pages for Your Devices 7. Communicating More Efficiently Using CoAP 8. Interoperability 9. Social Interaction with Your Devices Using XMPP 10. The Controller 11. Product Life Cycle 12. Concentrators and Bridges 13. Using an Internet of Things Service Platform 14. IoT Harmonization 15. Security for the Internet of Things 16. Privacy 17. Other Books You May Enjoy

Illustrating measurement results

Following image shows how our measured quantity behaves. The light sensor is placed in broad daylight on a sunny day, so it's saturated. Things move in front of the sensor, creating short dips. The thin blue line is a scaled version of our raw input A0. Since this value is event based, it is being reported more often than once a second. Our red curve is our measured, and corrected, ambient light value, in percent. The dots correspond to our second values. Notice that the first two spikes are removed and don't affect the measurement, which remains close to 100%. Only the larger dips affect the measurement. Also, notice the small delay inherent in our algorithm. It is most noticeable if there are abrupt changes:

Removal of spikes

If we, on the other hand, have a very noisy input, our averaging algorithm helps our measured value to stay...

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