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ATMEGA_MOTOR/ATMEGA_MOTOR.ino

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+/*
+SparkFun Inventor's Kit 
+Example sketch 12
+
+SPINNING A MOTOR
+
+  Use a transistor to spin a motor at different speeds.
+  We'll also show you how to input data from the serial port
+  (see the serialSpeed() function below).
+
+  Motors are the basis for thousands of things in our daily lives,
+  and the Arduino can control them. Here we'll use pulse-width
+  modulation (PWM) to vary the speed of a motor.
+
+  The Arduino pins are strong enough to light small LEDs (up to
+  40 milliAmps), but they're not strong enough to run motors and
+  other power-hungry parts. (This motor needs 50-100mA).
+  Because the motor needs more current than an Arduino pin can
+  provide, we'll use a transistor to do the heavy lifting.
+  A transistor is a solid-state switch. When we give it a small
+  amount of current, it can switch a much larger current.
+  The transistors in your kit (2N2222) can switch up to 200mA.
+
+  You can turn a transistor on and off using the digitalWrite()
+  function, but you can also use the analogWrite() function to
+  vary the speed of the motor. The analogWrite() function pulses
+  a pin, varying the width of the pulse from 0% to 100%. We call
+  this technique "PWM", for "Pulse-Width Modulation".
+
+  One thing to keep in mind is that when you lower the speed of
+  a motor using PWM, you're also reducing the torque (strength)
+  of the motor. For PWM values below 50 or so, the motor won't have
+  enough torque to start spinning. It will start spinning when you
+  raise the speed a bit.
+
+Hardware connections:
+
+  Transistor:
+
+    The transistor has three pins. Looking at the flat side with the
+    pins down, the order is COLLECTOR, BASE, EMITTER.
+
+    Connect the black wire on the motor to the
+    COLLECTOR pin on the transistor.
+
+    Connect the BASE pin through a 330 Ohm resistor to
+    digital pin 9.
+
+    Connect the EMITTER pin to GND.
+
+  Motor:
+
+    You've already connected the black wire on the motor to the
+    COLLECTOR pin on the transistor.
+
+    Connect the other (red) wire on the motor to 5V.
+
+  Flyback diode:
+
+    When the motor is spinning and suddenly turned off, the
+    magnetic field inside it collapses, generating a voltage spike.
+    This can damage the transistor. To prevent this, we use a
+    "flyback diode", which diverts the voltage spike "around" the
+    transistor.
+
+    Connect the side of the diode with the band (cathode) to 5V
+    Connect the other side of the diode (anode) to the black wire
+    on the motor.
+
+This sketch was written by SparkFun Electronics,
+with lots of help from the Arduino community.
+This code is completely free for any use.
+Visit http://learn.sparkfun.com/products/2 for SIK information.
+Visit http://www.arduino.cc to learn about the Arduino.
+
+Version 2.0 6/2012 MDG
+*/
+
+// We'll be controlling the motor from pin 9.
+// This must be one of the PWM-capable pins.
+
+const int motorPin = 9;
+
+
+void setup()
+{
+  // Set up the motor pin to be an output:
+
+  pinMode(motorPin, OUTPUT);
+
+  // Set up the serial port:
+
+  Serial.begin(9600);
+}
+
+
+void loop()
+{
+  // Here we've used comments to disable some of the examples.
+  // To try different things, uncomment one of the following lines
+  // and comment the other ones. See the functions below to learn
+  // what they do and how they work.
+
+  // motorOnThenOff();
+  // motorOnThenOffWithSpeed();
+  // motorAcceleration();
+     serialSpeed();
+}
+
+
+// This function turns the motor on and off like the blinking LED.
+// Try different values to affect the timing.
+
+void motorOnThenOff()
+{
+  int onTime = 3000;  // milliseconds to turn the motor on
+  int offTime = 3000; // milliseconds to turn the motor off
+
+  digitalWrite(motorPin, HIGH); // turn the motor on (full speed)
+  delay(onTime);                // delay for onTime milliseconds
+  digitalWrite(motorPin, LOW);  // turn the motor off
+  delay(offTime);               // delay for offTime milliseconds
+}
+
+
+// This function alternates between two speeds.
+// Try different values to affect the timing and speed.
+
+void motorOnThenOffWithSpeed()
+{
+  int Speed1 = 200;  // between 0 (stopped) and 255 (full speed)
+  int Time1 = 3000;  // milliseconds for speed 1
+
+  int Speed2 = 50;   // between 0 (stopped) and 255 (full speed)
+  int Time2 = 3000;  // milliseconds to turn the motor off
+
+  analogWrite(motorPin, Speed1);  // turns the motor On
+  delay(Time1);                   // delay for onTime milliseconds
+  analogWrite(motorPin, Speed2);  // turns the motor Off
+  delay(Time2);                   // delay for offTime milliseconds
+}
+
+
+// This function slowly accelerates the motor to full speed,
+// then back down to zero.
+
+void motorAcceleration()
+{
+  int speed;
+  int delayTime = 20; // milliseconds between each speed step
+
+  // accelerate the motor
+
+  for(speed = 0; speed <= 255; speed++)
+  {
+    analogWrite(motorPin,speed);    // set the new speed
+    delay(delayTime);               // delay between speed steps
+  }
+
+  // decelerate the motor
+
+  for(speed = 255; speed >= 0; speed--)
+  {
+    analogWrite(motorPin,speed);    // set the new speed
+    delay(delayTime);               // delay between speed steps
+  }
+}
+
+
+// This function will let you type a speed into the serial
+// monitor window. Open the serial monitor using the magnifying-
+// glass icon at the top right of the Arduino window. Then
+// type your desired speed into the small text entry bar at the
+// top of the window and click "Send" or press return. The motor
+// will then operate at that speed. The valid range is 0 to 255.
+
+void serialSpeed()
+{
+  int speed;
+
+  Serial.println("Type a speed (0-255) into the box above,");
+  Serial.println("then click [send] or press [return]");
+  Serial.println();  // Print a blank line
+
+  // In order to type out the above message only once,
+  // we'll run the rest of this function in an infinite loop:
+
+  while(true)  // "true" is always true, so this will loop forever.
+  {
+    // First we check to see if incoming data is available:
+
+    while (Serial.available() > 0)
+    {
+      // If it is, we'll use parseInt() to pull out any numbers:
+
+      speed = Serial.parseInt();
+
+      // Because analogWrite() only works with numbers from
+      // 0 to 255, we'll be sure the input is in that range:
+
+      speed = constrain(speed, 0, 255);
+
+      // We'll print out a message to let you know that the
+      // number was received:
+
+      Serial.print("Setting speed to ");
+      Serial.println(speed);
+
+      // And finally, we'll set the speed of the motor!
+
+      analogWrite(motorPin, speed);
+    }
+  }
+}
+