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Internet of Things with Python

You're reading from   Internet of Things with Python Create exciting IoT solutions

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Product type Paperback
Published in May 2016
Publisher Packt
ISBN-13 9781785881381
Length 388 pages
Edition 1st Edition
Languages
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Author (1):
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Gaston C. Hillar Gaston C. Hillar
Author Profile Icon Gaston C. Hillar
Gaston C. Hillar
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Table of Contents (13) Chapters Close

Preface 1. Understanding and Setting up the Base IoT Hardware FREE CHAPTER 2. Working with Python on Intel Galileo Gen 2 3. Interacting with Digital Outputs with Python 4. Working with a RESTful API and Pulse Width Modulation 5. Working with Digital Inputs, Polling and Interrupts 6. Working with Analog Inputs and Local Storage 7. Retrieving Data from the Real World with Sensors 8. Displaying Information and Performing Actions 9. Working with the Cloud 10. Analyzing Huge Amounts of Data with Cloud-based IoT Analytics A. Exercise Answers Index

Wiring a photoresistor to an analog input pin


Now, we will use a photoresistor, that is, a light sensor, specifically, an electronic component that provides a variable resistor that changes the resistor value based on the incident light intensity. As the incident light intensity increases, the resistance of the photoresistor decreases, and vice versa.

Tip

A photoresistor is also known as an LDR (short for Light-Dependent Resistor) or photocell. Bear in mind that pohotoresistors are not the best components to sense light with great accuracy. However, they are extremely useful to easily determine whether we are in a dark environment when we don't have problems with latencies that can reach one second.

We cannot measure a resistance value with our board. However, we can read voltage values, and therefore, we will use a voltage divider configuration that will include the photoresistor as one of its two resistors. The voltage divider will output a high voltage value when the photoresistor receives...

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