arduino - mechatronics engineering...

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4th Year- Mechatronics Major

Prof. Dr. Magdy M. Abdelhameed

Course Code: MDP 454, Course Name: Mechatronics (2), Second Semester 2014

• Prof. Dr. Magdy M. Abdelhameed

Arduino

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Microcontroller Platform

Okay… but what’s a Microcontroller?

Tiny, self-contained computers in an IC

Often contain peripherals

Different packages available

Vast array of size and power available

What is Arduino?

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Students, hobbyist, artists & designers

“open source hardware”Open Source Physical Computing Platform

open sourcefree to inspect & modify

communitywiki, forums, tutorials

Why Arduino?

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InputSensors (buttons, light sensors, ultrasound, …)

Digital Input (Serial, SPI, I2C)

OutputLEDs & Lasers

LCD/OLED/Touch Displays

Speakers

Motors, Servos, Steppers

Control and CommunicationDrive other machinery

Directly or using a communication protocol

What can it do?

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Sensors

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Arduino models differ in design but all share some basicfunctionality

AVR MicrocontrollerAtmel AVR Mega168 or AVR Mega 328

Powered either directly or via USB power

CommunicationsSerial (older models)

USB (most models)

Connections to a USB interface (smaller models)

Pins for various functions

Arduino hardware

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Pins 0-13 (GPIO pins)

•

Either input our output (default to input)•

Can output 40 mA•

•

•

Digital pins

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Switching without Pull-up and pull-down resistors

Digital pins

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Switching with Pull-up and pull-down resistors

Pull-upPull-down

Digital pins

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What happens if we Digital Read a pin that is not connected?•20K internal pull-up resistor•

Serial pins 0 (RX) and 1 (TX). Connected to FTDI USB-to-TTL•Pin 13 is different (input) (RES + LED)•Analogue pins A0-A5 can be used as digital pins 14-19 (GPIO)•Read up to 5V. Don’t fry your pin!•

Digital pins

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PWM used to create analogue output on digital pins•

Simulate voltage between 5V and 0V using square waves•(signal switching between on and off)

Pins 3, 5, 6, 9, 10, and 11•

Pulse Width Modulation (PWM)

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••(signal switching between on and off)

•

Pins A0-A5

10 bit resolution (from 0-5V to int 0-1023)

100 microseconds (0.0001 s) to read an analog input,

maximum reading rate is about 10,000 times a second.

Analogue pins

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ICSP (In Circuit Serial Programming) directly•program AVR micro-controllers

I2C / TWI (Two-wire interface) communication•Inter IC control•Arduino analog input A4 = I2C SDA (serial data line)•Arduino analog input A5 = I2C SCL (serial clock line)•

External interrupts•Event-handling without polling•Interrupt 0 (on digital pin 2) and 1 (on digital pin 3)•

Analogue reference• (Set analogue reference for ADC)

Other pins

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Arduino

Environment

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The Arduino Environment

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Board Type

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Serial (COM) port

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The Environment

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Parts of the code

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• Comments can be anywhere

Comments

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• Comments created with // or /*

and */

Comments

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and */

• Comments do not affect code

Comments

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and */

• Comments do not affect code

• You may not need comments,

but think about the community!

Comments

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The equals sign

= is used to assign a value

== is used to compare values

Operators

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And & Or

&& is “and”

|| is “or”

Operators

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–Basic variable types:

–Boolean

–Integer

–Character

–String

Variables

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–Boolean: boolean variableName;

Declaring variables

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–Integer: int variableName;

Declaring variables

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–Character: char variableName;

Declaring variables

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–Character: char variableName;

–String: stringName [ ];

Declaring variables

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–Boolean: variableName = true;

–or variableName = false;

Assigning variables

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–Integer: variableName = 32767;

–or variableName = -32768;

Assigning variables

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–Integer: variableName = 32767;

–or variableName = -32768;

–Character: variableName = „A‟;

–or stringName = “SparkFun”;

Assigning variables

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Variable Scope

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void setup ( ) { }

• The setup function comes before

• the loop function and is necessary

• for all Arduino sketches

Setup

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void setup ( ) { }

• The setup header will never change,

• everything else that occurs in setup

• happens inside the curly brackets

Setup

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• Outputs are declare in setup, this is done by using the pinMode function

• This particular example declares digital pin # 13 as an output, remember to use CAPS

Setup

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• Serial communication also begins in setup

• This particular example declares Serial communication at a baud rate of 9600. More on Serial later...

Setup

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• You can also create internal pullup resistors in setup, to do so digitalWrite the pin HIGH

• This takes the place of the pullup resistors currently on your circuit 7 buttons

Setup

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Setup, Interruptsvoid setup ( ) {

attachInterrupt (interrupt, function, mode) }

–You can designate an interrupt

function to Arduino pins # 2 and 3

–This is a way around the linear

processing of Arduino

Setup

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–Interrupt: the number of the interrupt, 0 or 1, corresponding to Arduino pins # 2

and 3 respectively

–Function: the function to call when the interrupt occurs

–Mode: defines when the interrupt should be triggered

Setup

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•LOW whenever pin state is low

•CHANGE whenever pin changes value

•RISING whenever pin goes from low to high

•FALLING whenever pin goes from low to high

–Don’t forget to CAPITALIZE

Setup

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if ( this is true ) { do this; }

If statements

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if ( this is true ) { do this; }If statements

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else { do this; }

Else

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• loop

• For

• while

Basic Repetition

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void loop ( ) { }Basic Repetition

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void loop ( ) { }

The “void” in the header is what the function will return (or spit out) when it happens, in this case it

returns nothing so it is void

Basic Repetition

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void loop ( ) { }

The “loop” in the header is what the function is called, sometimes you make the name up, sometimes (like loop) the function already

has a name

Basic Repetition

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void loop ( ) { }

The “( )” in the header is where you declare any variables that you are “passing” (or

sending) the function, the loop function is never “passed” any variables

Basic Repetition

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void loop ( ) { }Basic Repetition

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for (int count = 0; count<10; count++) { //for action code goes here//this could be anything

}

Basic Repetition

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for (int count = 0; count<10; count++){//for action code goes here}

Basic Repetition

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for (int count = 0; count<10; count++) {//for action code goes here}

Basic Repetition

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while ( count<10 ) {//while action code goes here}

Basic Repetition

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while ( count<10 ) {//while action code goes here//should include a way to change count//variable so the computer is not stuck//inside the while loop forever}

Basic Repetition

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while ( count<10 ) {//looks basically like a “for” loop //except the variable is declared before//and incremented inside the while //loop}

Basic Repetition

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Or maybe:while ( digitalRead(buttonPin)==1 ) {//instead of changing a variable//you just read a pin so the computer//exits when you press a button//or a sensor is tripped}

Basic Repetition

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Arduino

Programming

Structure

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Declare variables at top

Initialize

setup() – run once at beginning, set pins

Running

loop() – run repeatedly, after setup()

Arduino “Software Layout”

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int ledPin = 13; – ledconnected to control pin 13

int aSensor = 0; – setupGlobal Variables

sensor 'aSensor' on analog pin 0

int statePin = LOW; – use thisto hold the state of a pin


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pinMode() – set a pin as inputor output

setup()

serial.Begin() – setup to `talk'to the computer


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pinMode(ledPin, Output); –set the pin `ledPin' as an output

setup()

serial.Begin(9600); – talk tothe computer at 9600 baud rate


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digitalWrite() – set a digital pin high/low

digitalRead() – read a digital pin’s state

analogRead() – read an analog pinloop()

analogWrite() – write an “analog” PWM value

delay() – wait an amount of time

millis() – get the current tim


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14 Digital IO (pins 0 - 13)

6 Analog In (pins 0 - 5)

6 Analog Out (pins 3, 5, 6, 9, 10, 11)

Input / Output

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Digital – only has two values: on/off

Analog – has many (infinite) values

Computers don’t really do analog - usequantization instead

Digital? Analog?

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Many states (Analog) or justtwo (HIGH/LOW - Digital)

Number of states (or “bins”) isresolution

Common computer resolutions:8-bit = 256 states

16-bit = 65,536 states

32-bit = 4,294,967,296 states

Digital? Analog?

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Sensors ActuatorsLDR / IR

SolenoidSwitch /

Stepper MotorPotentiometer /Joystick / Piezo

Accelerometer Other CircuitsUltrasonic

Prototype shieldsIndicators

Special ICsLED / Lamps

Buzzers

I/O to/from What?

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Install latest Arduino IDE from arduino.ccvoid setup(){ Run Arduino IDE

// start serial port at 9600 bps:Write the code on the left into the editor

Serial.begin(9600);Compile / Verify the code by clicking the play}

button

Before uploading your sketch, check the board andvoid loop()the serial port are correct for your Arduino and for

{ your computer

Serial.print("Hello World!\n\r");Menu -> Tools -> Board

// wait 2sec for next reading:Menu -> Tools -> Serial Portdelay(2000);

} Upload the code from the computer to theArduino using the upload button

Hello World!

http://www.arduino.cc/

http://www.arduino.cc/

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Turn Led on and off according to the byte coming from the serial port, if a zero byte then the Led off else the Led on.

LED Blink

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/* Blinking LED ---* turns on and off a light emitting diode(LED) connected to a digital* pin, based on data coming over serial*/

int ledPin = 13; // LED connected to digital pin 13

int inByte = 0;

void setup()

{

pinMode(ledPin, OUTPUT); // sets the digital pin as output

Serial.begin(19200); // initiate serial communication

}

void loop()

{

while (Serial.available()>0) {

inByte = Serial.read();

}

if (inByte>0) {

digitalWrite(ledPin, HIGH); // sets the LED on

} else {

digitalWrite(ledPin, LOW); // sets the LED off

}

}

LED Blink

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/* Blinking LED ---* turns on and off a light emitting diode(LED) connected to a digital* pin, based on data coming over serial*/ Initialiseint ledPin = 13; // LED connected to digital pin 13

some of theint inByte = 0;

void setup() variables{



}

void loop()

{


inByte = Serial.read();

}

if (inByte>0) {


} else {


}

}

LED Blink

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int inByte = 0;

void setup()

{



}

void loop()

{ Setup LED pin andwhile (Serial.available()>0) {

inByte = Serial.read(); serial connection}

if (inByte>0) {


} else {


}

}

LED Blink

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int inByte = 0;

void setup()

{



} Loop - Reading thevoid loop() serial for info, when{


inByte = Serial.read(); something is received}

if (inByte>0) {turn LED on LED onthe

digitalWrite(ledPin, HIGH); // sets the

} else {


}

}

LED Blink

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Write Arduino code that uses to turn led on (on pin 13) when the button status is high (on pin 7) and led off when the button status is low; Also send this status via serial port with baud rate 19600.

Digital Input/ Output

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/* Digital reading, turns on and off a light emitting diode (LED) connected to digital* pin 13, when pressing a pushbutton attached to pin 7. It illustrates the concept of* Active-Low, which consists in connecting buttons using a 1K to 10K pull-up resistor.*/

int ledPin = 13; // choose the pin for the LED

int inPin = 7; // choose the input pin (button)

int buttonval = 0; // variable for reading the pin status

void setup() {

pinMode(ledPin, OUTPUT); // set LED as output

pinMode(inPin, INPUT); // set pushbutton as input

Serial.begin(19200); // start serial communication to computer

}

void loop() {

buttonval = digitalRead(inPin); // read the pin and get the button's state

if (buttonval == HIGH) { // check if the input is HIGH (button released)

digitalWrite(ledPin, LOW); // turn LED OFF

Serial.write('0'); // Button off (0) sent to computer

} else {

digitalWrite(ledPin, HIGH); // turn LED ON

Serial.write('1'); // Button on (1) sent to computer

}

}


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Initialiseint ledPin = 13; // choose the pin for the LED

int inPin = 7; // choose the input pin (button) some of theint buttonval = 0; // variable for reading the pin status

variablesvoid setup() {




}

void loop() {





} else {



}

}


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int ledPin = 13; // choose the pin for the LED

Setup LED pin,

int inPin = 7; // choose the input pin (button)

int buttonval = 0; // variable for reading the pin status

switch pin and

void setup() {

serial connection




}

void loop() {





} else {



}

}


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Loop - Reading theint ledPin = 13; // choose the pin for the LED

int inPin = 7; // choose the input pin (button) button for info, when

int buttonval = 0; // variable for reading the pin status button is press turnvoid setup() {


pinMode(inPin, INPUT); // set pushbutton asthe LED on and input


signal the computer

}

void loop() {

Of the button's state

change

buttonval = digitalRead(inPin); // read the pin and get




} else {



}

}


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Thank You For Your Attention!

Questions?

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