Introdução à plataforma ArduinoFaculdade SATC, Criciúma - Santa Catarina 21-22 de outubro, 2014...

Introdução Sistemas SOM (System On Module) Plataforma Arduino Descrição de periféricos Exemplos

Introdução à plataforma ArduinoPARTE I

Prof. Dr. Juan C. Cutipa Luque

Departamento de Engenharia ElétricaFaculdade SATC

Associação Beneficente da Indústria Carbonífera de Santa Catarina

Workshop em Engenharia Elétrica - 2014Faculdade SATC, Criciúma - Santa Catarina

21-22 de outubro, 2014

Prof. Dr. Juan C. Cutipa Luque VSNT


Conteúdo

1 Introdução

2 Sistemas SOM (System On Module)

3 Plataforma Arduino

4 Descrição de periféricos

5 Exemplos


Qual é o propósito?


SOM - System On Module



Plataforma Arduino



Periféricos



Exemplo 1

Ligar o arduíno na porta USB. Abra os software e na aba e configure"Tools>Board>Arduino Uno". Utilize os ícones "Verify"e "Upload"paracompilar e carregar o código no arduíno.


void setup() {// put your setup code here , to run once:

}

void loop() {// put your main code here , to run repeatedly:

}


Exemplo 2

Led intermitente pela saída digital 13. Logo de comprovar ofuncionamento correto, mude o "delay"para 500.


/*BlinkTurns on an LED on for one second , then off for one second ,

repeatedly.

This example code is in the public domain.*/

// Pin 13 has an LED connected on most Arduino boards.// give it a name:int led = 13;

// the setup routine runs once when you press reset:void setup() {

// initialize the digital pin as an output.pinMode(led , OUTPUT);

}

// the loop routine runs over and over again forever:void loop() {

digitalWrite(led , HIGH); // turn the LED on (HIGH is the voltagelevel)

delay (1000); // wait for a seconddigitalWrite(led , LOW); // turn the LED off by making the

voltage LOWdelay (1000); // wait for a second

}


Exemplo 3

Trabalhando com número flotantes e os possíveis erros de aproximação(adaptado de [1]). Utilize o visualizar de dados (Tools>Serial Monitor).

Tipo de número | bytes | faixa | uso


/** Floating -point example* This sketch initialized a float value to 1.1* It repeatedly reduces the value by 0.1 until the value is 0*/

float value = 1.1;

void setup(){

Serial.begin (9600);}

void loop(){

value = value - 0.1; // reduce value by 0.1 each time throughthe loop

if( value == 0)Serial.println("The value is exactly zero");

else if(almostEqual(value , 0)){

Serial.print("The value ");Serial.print(value ,7); // print to 7 decimal placesSerial.println(" is almost equal to zero");

}else

Serial.println(value);

delay (100);}

// returns true if the difference between a and b is small// set value of DELTA to the maximum difference considered to be

equalboolean almostEqual(float a, float b){

const float DELTA = .00001; // max difference to be almost equalif (a == 0) return fabs(b) <= DELTA;if (b == 0) return fabs(a) <= DELTA;return fabs((a - b) / max(fabs(a), fabs(b))) <= DELTA ;

}

Continuação// returns true if the difference between a and b is small// set value of DELTA to the maximum difference considered to be

equalboolean almostEqual(float a, float b){

const float DELTA = .00001; // max difference to be almost equalif (a == 0) return fabs(b) <= DELTA;if (b == 0) return fabs(a) <= DELTA;return fabs((a - b) / max(fabs(a), fabs(b))) <= DELTA ;

}


Exemplo 4

Acionamento de um Led pelo switch da entrada digital. Uso de resistorpull-down (adaptado de [1]).


/*Pushbutton sketcha switch connected to pin 2 lights the LED on pin 13

*/

const int ledPin = 13; // choose the pin for the LEDconst int inputPin = 2; // choose the input pin (for a

pushbutton)

void setup() {pinMode(ledPin , OUTPUT); // declare LED as outputpinMode(inputPin , INPUT); // declare pushbutton as input

}

void loop(){int val = digitalRead(inputPin); // read input valueif (val == HIGH) // check if the input is HIGH{

digitalWrite(ledPin , HIGH); // turn LED on if switch ispressed

}else{

digitalWrite(ledPin , LOW); // turn LED off}

}


Exemplo 5

Acionamento de um Led pelo switch sem necessidade de resistorpull-down externo (adaptado de [1]).


/*Pullup sketcha switch connected to pin 2 lights the LED on pin 13

*/

const int ledPin = 13; // output pin for the LEDconst int inputPin = 2; // input pin for the switch

void setup() {pinMode(ledPin , OUTPUT);pinMode(inputPin , INPUT);digitalWrite(inputPin ,HIGH); // turn on internal pull -up on the

inputPin}void loop(){

int val = digitalRead(inputPin); // read input valueif (val == HIGH) // check if the input is HIGH{

digitalWrite(ledPin , HIGH); // turn LED OFF}else{

digitalWrite(ledPin , LOW); // turn LED ON}

}


Exemplo 6

Supressão de falso contato (’debouncing’), causado pelo contatomecânico dos ’switchs’ e pulsadores. O ’sketch’ evita que falsos contatossejam percebidos. Esses falsos contatos se geram nos instantes deabertura e de fechadura dos ’switch’ e dos pulsadores (adaptado de [1]).

Imagens de internet usadas para fins ilustrativos


/** Debounce sketch* a switch connected to pin 2 lights the LED on pin 13* debounce logic prevents misreading of the switch state*/

const int inputPin = 2; // the number of the input pinconst int ledPin = 13; // the number of the output pinconst int debounceDelay = 10; // milliseconds to wait until stable

// debounce returns true if the switch in the given pin is closedand stable

boolean debounce(int pin){

boolean state;boolean previousState;

previousState = digitalRead(pin); // store switch statefor(int counter =0; counter < debounceDelay; counter ++){

delay (1); // wait for 1 millisecondstate = digitalRead(pin); // read the pinif( state != previousState){

counter = 0; // reset the counter if the state changespreviousState = state; // and save the current state

}}// here when the switch state has been stable longer than the

debounce periodreturn state;

}

void setup(){

pinMode(inputPin , INPUT);pinMode(ledPin , OUTPUT);

}

void loop(){

if (debounce(inputPin)){

digitalWrite(ledPin , HIGH);}

}

Continuaçãovoid setup(){

pinMode(inputPin , INPUT);pinMode(ledPin , OUTPUT);

}

void loop(){

if (debounce(inputPin)){

digitalWrite(ledPin , HIGH);}

}


Exemplo 7

Determinação do tempo em que um ’switch’ é pressionado. O pulsador éconectado na entrada digital 2, como no exemplo anterior (semnecessidade de resistores externos pull-up ou pull-down). Use o monitorserial para visualizar a temporização [1].


/*SwitchTime sketchCountdown timer that decrements every tenth of a secondlights an LED when 0Pressing button increments count , holding button down increases rate

of increment*/const int ledPin = 13; // the number of the output

pinconst int inPin = 2; // the number of the input

pin

const int debounceTime = 20; // the time in millisecondsrequired

// for the switch to bestable

const int fastIncrement = 1000; // increment faster afterthis many

// millisecondsconst int veryFastIncrement = 4000; // and increment even faster

after// this many milliseconds

int count = 0; // count decrements everytenth of a

// second until reaches 0

void setup(){

pinMode(inPin , INPUT);digitalWrite(inPin , HIGH); // turn on pull -up resistorpinMode(ledPin , OUTPUT);Serial.begin (9600);

}

void loop(){

int duration = switchTime ();if( duration > veryFastIncrement)

count = count + 10;else if ( duration > fastIncrement)

count = count + 4;else if ( duration > debounceTime)

count = count + 1;

else{

// switch not pressed so service the timerif( count == 0)

digitalWrite(ledPin , HIGH); // turn the LED on if the countis 0

else{

digitalWrite(ledPin , LOW); // turn the LED off if the countis not 0

count = count - 1; // and decrement the count}

} Serial.println(count);delay (100);

}

// return the time in milliseconds that the switch has been inpressed (LOW)

long switchTime (){

// these variables are static - see Discussion for an explanationstatic unsigned long startTime = 0; // the time the switch state

change was first detectedstatic boolean state; // the current state of the

switch

if(digitalRead(inPin) != state) // check to see if the switch haschanged state

{state = ! state; // yes , invert the statestartTime = millis (); // store the time

}if( state == LOW)

return millis () - startTime; // switch pushed , return time inmilliseconds

elsereturn 0; // return 0 if the switch is not pushed (in the HIGH

state);}

Continuaçãovoid loop(){

int duration = switchTime ();if( duration > veryFastIncrement)

count = count + 10;else if ( duration > fastIncrement)

count = count + 4;else if ( duration > debounceTime)

count = count + 1;

else{

// switch not pressed so service the timerif( count == 0)

digitalWrite(ledPin , HIGH); // turn the LED on if the countis 0

else{

digitalWrite(ledPin , LOW); // turn the LED off if the countis not 0

count = count - 1; // and decrement the count}

} Serial.println(count);delay (100);

}

Continuação// return the time in milliseconds that the switch has been in

pressed (LOW)long switchTime (){

// these variables are static - see Discussion for an explanationstatic unsigned long startTime = 0; // the time the switch state

change was first detectedstatic boolean state; // the current state of the

switch

if(digitalRead(inPin) != state) // check to see if the switch haschanged state

{state = ! state; // yes , invert the statestartTime = millis (); // store the time

}if( state == LOW)

return millis () - startTime; // switch pushed , return time inmilliseconds

elsereturn 0; // return 0 if the switch is not pushed (in the HIGH

state);}


Exemplo 8

Entrada analógica A0 para utilizar sensor LDR (resistor dependente deluz) [2]. O tempo de liga e desliga do Led 13 mudará em proporção daquantidade de iluminação.


/* Created by David Cuartiellesmodified 30 Aug 2011By Tom Igoe

This example code is in the public domain.

http :// arduino.cc/en/Tutorial/AnalogInput

*/

int sensorPin = A0; // select the input pin for the potentiometerint ledPin = 13; // select the pin for the LEDint sensorValue = 0; // variable to store the value coming from the

sensor

void setup() {// declare the ledPin as an OUTPUT:pinMode(ledPin , OUTPUT);

}

void loop() {// read the value from the sensor:sensorValue = analogRead(sensorPin);// turn the ledPin ondigitalWrite(ledPin , HIGH);// stop the program for <sensorValue > milliseconds:delay(sensorValue);// turn the ledPin off:digitalWrite(ledPin , LOW);// stop the program for for <sensorValue > milliseconds:delay(sensorValue);

}


Exemplo 9

Uso da saída PWM para iluminação de um Led. A frequência do PWM éde aproximadamente 490 Hz. No Arduino Uno e similares, os pinos 5 e 6têm frequência de 980 Hz. No Arduino Leonardo, os pinos 3 e 11trabalham a 980 Hz. O Arduino Due tem DAC (conversores analógicosdigitais).


int ledPin = 9; // LED connected to digital pin 9

void setup() {// nothing happens in setup

}

void loop() {// fade in from min to max in increments of 5 points:for(int fadeValue = 0 ; fadeValue <= 255; fadeValue +=5) {

// sets the value (range from 0 to 255):analogWrite(ledPin , fadeValue);// wait for 30 milliseconds to see the dimming effectdelay (30);

}

// fade out from max to min in increments of 5 points:for(int fadeValue = 255 ; fadeValue >= 0; fadeValue -=5) {

// sets the value (range from 0 to 255):analogWrite(ledPin , fadeValue);// wait for 30 milliseconds to see the dimming effectdelay (30);

}}


Referências

[1] Michael Margolis. Arduino Cookbook. Second Edition. Publisher:O’Reilly Media. 2011.[2] Arduino. Página web oficial. www.arduino.cc.


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Introdução à plataforma ArduinoFaculdade SATC, Criciúma - Santa Catarina 21-22 de outubro, 2014...

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