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Internet of Things Programming with JavaScript

You're reading from   Internet of Things Programming with JavaScript Get the best out of Arduino and Raspberry Pi Zero to develop Internet of Things projects using JavaScript

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Product type Paperback
Published in Feb 2017
Publisher Packt
ISBN-13 9781785888564
Length 298 pages
Edition 1st Edition
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Author (1):
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Ruben Oliva Ramos Ruben Oliva Ramos
Author Profile Icon Ruben Oliva Ramos
Ruben Oliva Ramos
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Table of Contents (10) Chapters Close

Preface 1. Getting Started with Raspberry Pi Zero 2. Connecting Things to the Raspberry Pi Zero FREE CHAPTER 3. Connecting Sensors - Measure the Real Things 4. Control-Connected Devices 5. Adding a Webcam to Monitor Your Security System 6. Building a Web Monitor and Controlling Devices from a Dashboard 7. Building a Spy Police with the Internet of Things Dashboard 8. Monitoring and Controlling Your Devices from a Smart Phone 9. Putting It All Together

Measuring the level of water in a recipient


Somtimes, we need to measure the level of water in a recipient, or if you want to see the level of water in a tank, it is a requirement to measure the levels of water that it has; so in this section, we will explain how to do this.

The sensor is Normally Open. When the water is over the limit, the contact opens, and it sends a signal to the Arduino board. We use pin number 2, which is a digital input:

We declare the variables and const in the program:

const int buttonPin = 2;     // the number of the input sensor pin 
const int ledPin =  13;      // the number of the LED pin 

We also define the states of the digital signals:

// variables will change: 
intbuttonState = 0;         // variable for reading the pushbutton status 

We configure the signals of the program, inputs, and outputs:

void setup() { 
  // initialize the LED pin as an output: 
pinMode(ledPin, OUTPUT); 
  // initialize the pushbutton pin as an input...
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