Arduino: Analog I/O

阿爾杜伊諾
Arduino: Lv. 2

Mutienliao.TW 智慧生活與創新設計, 2013-03-25

Analog Out

Analog Out
類比輸出

Analog Output Arduino 的PWM pin只有3,5,6,9,10,11

PWM (Pulse Width Modulation)
電腦與微處理器是不可能實際輸出類比的電壓(僅能0~5V)。

但我們可以假造出類似的效果。
若快速在兩個電壓中做切換，我們可以得到⼀一個平均值：

Output Voltage = High_time(%) * Max_Voltage

Arduino 的PWM pin只有3,5,6,9,10,11

類比輸出0~5V對應的數值為0~255
analogWrite( pin, val )

#4 | Fade 實作呼吸燈的效果

#4的練習程式，在 File > Examples > Basic > Fade

int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by

void setup() {
// declare pin 9 to be an output:
pinMode(9, OUTPUT);
}

void loop() {
// set the brightness of pin 9:
analogWrite(9, 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);
}

#5 | Fade_and_Blink 實作呼吸燈與LED閃爍共存：活用millis()來進行多工

#5的練習程式，在 http://mutienliao.tw/arduino/Fade_and_Blink.pde
const int ledPin = 13; // the number of the LED pin for blink
const int fadePin = 9; // the number of the LED pin for fade

int ledState = LOW; // ledState used to set the LED
long previousMillis = 0; // will store last time LED was updated

long interval = 1000; // interval at which to blink (milliseconds)

int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by

void setup() {
pinMode(ledPin, OUTPUT);
pinMode(fadePin, OUTPUT);
}

void loop()
{
unsigned long currentMillis = millis();

if(currentMillis - previousMillis > interval) {
previousMillis = currentMillis;

if (ledState == LOW)
ledState = HIGH;
else
ledState = LOW;

digitalWrite(ledPin, ledState);
}

analogWrite(fadePin, brightness);

brightness = brightness + fadeAmount;

if (brightness == 0 || brightness == 255) {
fadeAmount = -fadeAmount ;
}
delay(30);
}

Analog In

Analog Input
類比輸入

Photocell

get value get value

get value

Arduino 的類比輸入使用A0~A5

類比輸入0~5V對應的數值為0~1023
analogRead( pin )

#10的練習程式，在 http://mutienliao.tw/arduino/analog_control.pde

int ledPin = 13; // LED connected to digital pin 13
int analogPin = 0; // photocell connected to analog pin 0
int val = 0;

void setup()
{
pinMode(ledPin, OUTPUT); // sets the digital pin as output
}

void loop()
{
val = analogRead(analogPin); // read the value from the sensor
if(val<80) {
digitalWrite(ledPin, HIGH); // sets the LED on
}
else {
digitalWrite(ledPin, LOW); // sets the LED off
}
delay(50);
}

修改#10的練習程式，取得analogRead進來的數值

int ledPin = 13; // LED connected to digital pin 13
int analogPin = 0; // photocell connected to analog pin 0
int val = 0;

void setup()
{
pinMode(ledPin, OUTPUT); // sets the digital pin as output
Serial.begin(9600);
}

void loop()
{
val = analogRead(analogPin); // read the value from the sensor
Serial.println(val);
if(val<80) {
digitalWrite(ledPin, HIGH); // sets the LED on
}
else {
digitalWrite(ledPin, LOW); // sets the LED off
}
delay(50);
}

我們可以先用Arduino Software提供的Serial Monitor來先測試Arduino板子端
傳來的訊息。

你要傳的訊息輸入

傳送來的訊息

546756456575456745674567447

baud rate 設定

#11的練習程式，在 File > Examples > Analog > AnalogInOutSerial

const int analogInPin = A0; // Analog input pin that the potentiometer is attached to
const int analogOutPin = 9; // Analog output pin that the LED is attached to

int sensorValue = 0; // value read from the pot
int outputValue = 0; // value output to the PWM (analog out)

void setup() {
// initialize serial communications at 9600 bps:
Serial.begin(9600);
}

void loop() {
// read the analog in value:
sensorValue = analogRead(analogInPin);
// map it to the range of the analog out:
outputValue = map(sensorValue, 0, 1023, 0, 255);
// change the analog out value:
analogWrite(analogOutPin, outputValue);

// print the results to the serial monitor:
Serial.print("sensor = " );
Serial.print(sensorValue);
Serial.print("t output = ");
Serial.println(outputValue);

// wait 10 milliseconds before the next loop
// for the analog-to-digital converter to settle
// after the last reading:
delay(10);
}

#10的練習程式， File > Examples > Analog > AnalogInput

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

void setup() {
// declare the ledPin as an OUTPUT:
}

void loop() {
// read the value from the sensor:
sensorValue = analogRead(sensorPin);
// turn the ledPin on
digitalWrite(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);
}

修改#10的練習程式，取得analogRead進來的數值

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

void setup() {
// declare the ledPin as an OUTPUT:
Serial.begin(9600);
}

void loop() {
// read the value from the sensor:
sensorValue = analogRead(sensorPin);
Serial.println(sensorValue);
// turn the ledPin on
digitalWrite(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);
}

Communication

Communication
溝通

Arduino 並不是真的透過USB來跟電腦溝通，而是透過RS-232 Serial的方式。

透過⼀一連串HIGH / LOW的編碼訊號，可以轉換成我們要的訊息：

不論電腦端用什麼軟體，只要能透過Serial port傳送訊息，就可以跟Arduino溝通。
故我們可以用 C/C++,VB, MAX/MSP,VVVV, Processing 或是FLASH(需要第三方軟體的幫助)

#12 | PC to Arduino #12的練習程式，在File > Example > Communication > PhysicalPixel

#13 | PC to Arduino #13的練習程式，在 http://mutienliao.tw/arduino/PC_to_Arduino_analog.pde

[Arduino] 在 File > Examples > Communication > Graph
#14 | Arduino to Processing
[Processing] 在 http://mutienliao.tw/processing/Graph.pde

[Arduino] 在 File > Examples > Communication > Dimmer
#15 | Processing to Arduino
[Processing] 在 http://mutienliao.tw/processing/Dimmer.pde

Arduino: Analog I/O

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