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Programming the BeagleBone

You're reading from  Programming the BeagleBone

Product type Book
Published in Jan 2016
Publisher
ISBN-13 9781784390013
Pages 180 pages
Edition 1st Edition
Languages

Table of Contents (21) Chapters

Programming the BeagleBone
Credits
About the Author
Acknowledgment
About the Reviewers
www.PacktPub.com
Preface
1. Cloud9 IDE 2. Blinking Onboard LEDs 3. Blinking External LEDs 4. Controlling LED Using a Push Button 5. Reading from Analog Sensors 6. PWM – Writing Analog Information 7. Internet of Things with BeagleBone 8. Physical Computing in Python 9. UART, I2C, and SPI Programming 10. Internet of Things using Python GPIO Control in Bash BeagleBone Capes
Pinmux and the Device Tree Index

Program to check light intensity


Write the following code in Cloud9 and save it as ldr.js. Run the program and check the output voltage. If the LDR is exposed to bright sunlight, you may get the output message—Looks like a bright sunny day. If this is not possible, point a torch on the LDR surface. You should see the voltage has increased. Based on voltage value, you can guess the light brightness and respond by sending an SMS/e-mail or turn on a smart bulb in case of low light condition. You can also change the intensity of bulb according to the light intensity detected. The code for ldr.js is as follows:

var b = require('bonescript');
var loopTime = 2000;
var LDR = 'P9_38';
var loopTimer = setInterval(readVoltageLoop, loopTime);

function readVoltageLoop()
{
  b.analogRead(LDR, printVoltage);
}

function printVoltage(pinObj)
{
  var volt = pinObj.value * 1.8;
  console.log("Voltage at input pin = " + volt.toPrecision(3));
  if( volt > 1.6 )
  {
    console.log("Looks like bright sunny...
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