Post on 12-Aug-2015
transcript
Fun with Arduino (Arduino-Uno)
-By Prof.Ravikumar Tiwari, Assistant Professor,G.H. Raisoni College of Engineering, Nagpurravikumar.tiwari@raisoni.nethttp://twitter.com/RaviTiwari90
What we will be learning..Getting Started with ArduinoArduino IDEProgramming the ArduinoPractice examples to learn
Little bit about programming• Code is case sensitive• Statements are commands and
must end with a semi-colon• Comments follow a // or begin
with /* and end with */
Terminology
Digital I/OpinMode(pin, mode)
◦Sets pin to either INPUT or OUTPUT
digitalRead(pin)◦Reads HIGH or LOW from a pin
digitalWrite(pin, value)◦Writes HIGH or LOW to a pin
Output pins can provide 40 mA of current
Arduino Timing• delay(ms)– Pauses for a few milliseconds
• delayMicroseconds(us)– Pauses for a few microseconds
Bits and Bytes
Bits & Bytes “The world isn't run by weapons
anymore, or energy, or money. It's run by little ones and zeroes, little bits of data. It's all just electrons”
For example, we measure weight with "ounces" and "pounds" (or grams and kilograms) and distances with "inches," "feet," and "miles" (or centimeters, meters and kilometers). Information has its own system of measurements:
Bits and BytesA single bit is either a zero or a
one. You can group bits together into
8 bits which is 1 byte. 1024 bytes (8192 bits) is one
Kilobyte (sometimes written KB).1024 KB (1048576 bytes) is one
Megabyte (MB)1024 MB is 1 Gigabyte (GB)
Bits and BytesQuick quiz! If your hard disk is 200
Gigabytes, how many bytes is that? Use a calculator with lots of digits! (highlight text below)
200 GB * 1024 = 204800 MB204800 MB * 1024 = 209715200 KB209715200 KB * 1024 = 214748364800 bytes!
Basics to get startedA program on Arduino is called as Sketch.Structure of Sketch: void setup() {
// put your setup code here, to run once:
}
void loop() { // put your main code here, to run repeatedly: }
setup() functionto initialize variables, pin modes,
start using libraries, etcThe setup function will only run
once, after each powerup or reset of the Arduino board
Loop() functionthe loop() function does precisely
what its name suggests, and loops consecutively, allowing your program to change and respond as it runs
Code in the loop() section of your sketch is used to actively control the Arduino board
Any line that starts with two slashes (//) will not be read by the compiler, so you can write anything you want after it
Example 1: Blink:-To turn LED ON and OFF
Blink: Codeinitialize pin 13 as an output pin
with the line pinMode(13, OUTPUT);
Blink: CodeIn the main loop, you turn the
LED on with the line: digitalWrite(13, HIGH); This supplies 5 volts to pin 13.
That creates a voltage difference across the pins of the LED, and lights it up.
turn it off with the line: digitalWrite(13, LOW);
Blink: Code…the delay()In between the on and the off,
you want enough time for a person to see the change,
so the delay() commands tell the Arduino to do nothing for 1000 milliseconds, or one second
UploadingFirst click on tick button to verify
the codeClick on the arrow button to
upload the code on arduino boardMake sure that you have selected
right port and right board
Try this oneTry generating some pattern on
series of LED’s (don’t use potentiometer)
Example2:Digital Read Serial
This example shows you how to monitor the state of a switch by establishing serial communication between your Arduino and your computer over USB
Connect three wires to the Arduino board
The first two to; connect to the two long vertical rows on the side of the breadboard to provide access to the 5 volt supply and ground
bb
The third wire goes from digital pin 2 to one leg of the pushbutton
That same leg of the button connects through a pull-down resistor (1 to 10 KOhms) to ground
The other leg of the button connects to the 5 volt supply
Digital Read SerialPushbuttons or switches connect two
points in a circuit when you press them. When the pushbutton is open (unpressed)
there is no connection between the two legs of the pushbutton, so the pin is connected to ground (through the pull-down resistor) and reads as LOW, or 0.
When the button is closed (pressed), it makes a connection between its two legs, connecting the pin to 5 volts, so that the pin reads as HIGH, or 1
Code: Digital Read Serialthe very first thing that you do
will in the setup function is to begin serial communications, at 9600 bits of data per second, between your Arduino and your computer with the line:
Serial.begin(9600); initialize digital pin 2, the pin that
will read the output from your button, as an input:
pinMode(2,INPUT);
QuizIf the Arduino transfers data at
9600 bits per second and you're sending 12 bytes of data, how long does it take to send over this information? (highlight text below)
12 bytes of data equals 12 * 8 = 96 bits of data. If we can transfer 9600 bits per second, then 96 bits takes 1/100th of a second!
Code: Digital Read SerialThe first thing you need to do in
the main loop of your program is to establish a variable to hold the information coming in from your switch
Call this variable sensorValue, and set it to equal whatever is being read on digital pin 2. You can accomplish all this with just one line of code:
int sensorValue = digitalRead(2);
Code: Digital Read SerialOnce the Arduino has read the
input, make it print this information back to the computer as a decimal value. You can do this with the command Serial.println() in our last line of code:
Serial.println(sensorValue); Last use delay(1); // delay in
between reads
Example3: Analog Read Serial
This example shows you how to read analog input from the physical world using a potentiometer
A potentiometer is a simple mechanical device that provides a varying amount of resistance when its shaft is turned
In this example you will monitor the state of your potentiometer after establishing serial communication between your Arduino and your computer
Analog Read SerialConnect the three wires
from the potentiometer to your Arduino board.
The first goes to ground from one of the outer pins of the potentiometer.
The second goes from 5 volts to the other outer pin of the potentiometer.
The third goes from analog input 0 to the middle pin of the potentiometer.
Analog Read SerialThe Arduino has a circuit inside called an
analog-to-digital converter that reads this changing voltage and converts it to a number between 0 and 1023
When the shaft is turned all the way in one direction, there are 0 volts going to the pin, and the input value is 0
When the shaft is turned all the way in the opposite direction, there are 5 volts going to the pin and the input value is 1023
Code: Analog Read Serialthe only thing that you do will in
the setup function is to begin serial communications, at 9600 bits of data per second, between your Arduino and your computer with the command:
Serial.begin(9600)
Code: Analog Read Serialin the main loop of your code, you need to
establish a variable to store the resistance value (which will be between 0 and 1023, perfect for an int datatype) coming in from your potentiometer:
int sensorValue = analogRead(A0); Finally, you need to print this information to
your serial window as a decimal (DEC) value. You can do this with the command Serial.println() in your last line of code:
Serial.println(sensorValue, DEC) delay(1); //to read
Example4: Fading of LEDDemonstrates the use of the
analogWrite() function in fading an LED off and on
AnalogWrite uses pulse width modulation (PWM), turning a digital pin on and off very quickly, to create a fading effect
Pulse Width Modulation (PWM)Pulse Width Modulation, or PWM, is a
technique for getting analog results with digital means
This on-off pattern can simulate voltages in between full on (5 Volts) and off (0 Volts) by changing the portion of the time the signal spends on versus the time that the signal spends off
If you repeat this on-off pattern fast enough with an LED for example, the result is as if the signal is a steady voltage between 0 and 5v controlling the brightness of the LED
PWM
Fading of LED
Code /*
Fade This example shows how to fade an LED on pin 9 using the analogWrite() function. This example code is in the public domain. */
int led = 9; // the pin that the LED is attached toint brightness = 0; // how bright the LED isint fadeAmount = 5; // how many points to fade the LED by
// the setup routine runs once when you press reset:void setup() { // declare pin 9 to be an output: pinMode(led, OUTPUT);}
// the loop routine runs over and over again forever:void loop() { // set the brightness of pin 9: analogWrite(led, brightness);
// change the brightness for next time through the loop: brightness = brightness + fadeAmount;
// reverse the direction of the fading at the ends of the fade: if (brightness == 0 || brightness == 255) { fadeAmount = -fadeAmount ; } // wait for 30 milliseconds to see the dimming effect delay(30); }
Referencehttps://www.arduino.cc/en/Tutoria
l/HomePage (great resource for arduino beginner)