Điều khiển động cơ bằng transitor - Hoc Arduino

int dc=11;

int speed;

void setup() {

  // initialize digital pin 13 as an output.

  pinMode(dc, OUTPUT);

  Serial.begin(9600);// mở cổng serial để giao tiếp PC

}

// the loop function runs over and over again forever

void loop() {

 int value=analogRead(A0);// đọc điện áp ở chân A0; giá trị luôn từ: 0-1023

 int speed=map(value,0,1023,0,255);

 Serial.println(speed);

  analogWrite(dc,speed);

}

//----------------------

/*

 Motor Control with a Transistor

 This example shows you how to control a motor's using a transistor.

 When a pushbutton on pin 2 is pressed, the Arduino will control a transistor

 via PWM, which will slowly ramp up the motor's speed, then slow it down.

 The circuit : 

 * momentary switch with one end connected to 5V, the other end connected 

   to GND through a 10-kilohm resistor, and digital pin 2.

 * TIP120 tranistor, with the Base connected to digital pin 9, the Emitter to ground,

   and the Collector to one lead from a 9V DC motor

 * a 9V battery, with the ground connected to the Arduino's ground, and the power

   connected to the motor

 * 1N4001 diode across the motor's leads, with the striped side conneted to the 9V

 The Arduino can only provide 40mA at 5V on its pins. Most motors require 

 more current and/or voltage to overcome intertia and run. A transistor

 can act as a digital switch, enabling the Arduino to control loads with 

 higher electrical requirements. 

 Created on 03 January 2013

 by Scott Fitzgerald 

 http://www.arduino.cc/en/Tutorial/TransistorMotorControl

 This example code is in the public domain.

 */

// give a name to digital pin 2, which has a pushbutton attached

int pushButton = 2;

// the transistor which controls the motor will be attached to digital pin 9

int motorControl = 9;

// the setup routine runs once when you press reset:

void setup() {

  // make the pushbutton's pin an input:

  pinMode(pushButton, INPUT);

  // make the transistor's pin an output:

  pinMode(motorControl, OUTPUT);  

}

// the loop routine runs over and over again forever:

void loop() {

  // read the state of the button and check if it is pressed

  if(digitalRead(pushButton) == HIGH){ 

    // ramp up the motor speed

    for(int x = 0; x <= 255; x++){

      analogWrite(motorControl, x);

      delay(50);

    }

    // ramp down the motor speed

    for(int x = 255; x >= 0; x--){

      analogWrite(motorControl, x);

      delay(50);

    }    

  }

  delay(1);        // delay in between reads for stability

}