/*
  Bluetooth Remote Projector Screen
 
This sketch controls a bluetooth enabled Arduino which runs a projector screen up and down.
 
 Created 27 Mar 2012
 modified xx Xxx 20xx
 by Brett Russell
 
 */
// Motor shield library
#include <AFMotor.h>

// Define Constants and Variables
AF_DCMotor motor(2, MOTOR12_1KHZ);  //create motor on number 2 port, 1KHz pwm
const int potPin = A0;	// pin that the pot is attached to
const int thresholdUp = 972;   	// the analog input threshold level that determines when the screen is up
const int thresholdDown = 51;	// the analog input threshold level that determines when the screen is down
byte command;
int screenPosition;

void setup()
{
  // initialize serial communications:
  Serial.begin(9600);
  
  // set motor speed, 250/255
  motor.setSpeed (250);

}

void loop()
{
  // Turn off motor after correct position is reached or full stop command is sent
  motor.run(RELEASE);
        
  // check if serial data is available
  if ( Serial.available() > 0 ) 
  {        
  	// write the serial command value
  	command = Serial.read();	// 1 = Down, 2 = Up, 3 = Full stop
  
        // Check screen position
        screenPosition = analogRead(potPin);
  	
  	// if the command sent is 1 and the screen is up, lower the screen
  	if (command == 1 && screenPosition > thresholdDown) 
  	{	
  		do
                {
                    // Run screen down
                    motor.run(FORWARD);
                    
                    // Check screen position
                    screenPosition = analogRead(potPin);
                    
                    // Check for new seriel commands
                    command = Serial.read();
                    
                }  // Keep the screen running while it is not down and there is no full stop
                   while (screenPosition > thresholdDown && command != 3);
  			
  	}
  		
  	// if the command sent is 2 and the screen is down, raise the screen
  	else if (command == 2 && screenPosition < thresholdUp)
  	{	
  		do
                {
                    // Run screen up
                    motor.run(BACKWARD);
                    
                    // Check screen position
                    screenPosition = analogRead(potPin);
                    
                    // Check for new seriel commands
                    command = Serial.read();
                    
                }  // Keep the screen running while it is not down and there is no full stop
                   while (screenPosition < thresholdUp && command != 3);
  		
  	}
  }
}