source: rtos_arduino/trunk/examples/PIXY/rca_app.cpp@ 236

#include "rca.h"

#include <SPI.h>  
#include <Pixy.h>

Pixy pixy;

#define X_CENTER        ((PIXY_MAX_X-PIXY_MIN_X)/2)       
#define Y_CENTER        ((PIXY_MAX_Y-PIXY_MIN_Y)/2)

class ServoLoop
{
public:
  ServoLoop(int32_t pgain, int32_t dgain);

  void update(int32_t error);
   
  int32_t m_pos;
  int32_t m_prevError;
  int32_t m_pgain;
  int32_t m_dgain;
};

ServoLoop panLoop(300, 500);
ServoLoop tiltLoop(500, 700);

ServoLoop::ServoLoop(int32_t pgain, int32_t dgain)
{
  m_pos = PIXY_RCS_CENTER_POS;
  m_pgain = pgain;
  m_dgain = dgain;
  m_prevError = 0x80000000L;
}

void ServoLoop::update(int32_t error)
{
  long int vel;
  char buf[32];
  if (m_prevError!=0x80000000)
  {     
    vel = (error*m_pgain + (error - m_prevError)*m_dgain)>>10;
    //sprintf(buf, "%ld\n", vel);
    //Serial.print(buf);
    m_pos += vel;
    if (m_pos>PIXY_RCS_MAX_POS) 
      m_pos = PIXY_RCS_MAX_POS; 
    else if (m_pos<PIXY_RCS_MIN_POS) 
      m_pos = PIXY_RCS_MIN_POS;
  }
  m_prevError = error;
}

void setup()
{
  Serial.begin(115200);
  Serial.print("Starting...\n");  
  pixy.init();
  pixy.setServos(PIXY_RCS_CENTER_POS, PIXY_RCS_CENTER_POS);      
}

void loop()
{ 
  static int i = 0;
  int j;
  uint16_t blocks;
  char buf[32]; 
  int32_t panError, tiltError;
  
  blocks = pixy.getBlocks();
  
  if (blocks)
  {
    panError = X_CENTER-pixy.blocks[0].x;
    tiltError = pixy.blocks[0].y-Y_CENTER;
    
    panLoop.update(panError);
    tiltLoop.update(tiltError);
    
    pixy.setServos(panLoop.m_pos, tiltLoop.m_pos);
    
    i++;
    
    // do this (print) every 50 frames because printing every
    // frame would bog down the Arduino
    if (i%50==0) 
    {
      sprintf(buf, "Detected %d:\n", blocks);
      Serial.print(buf);
      for (j=0; j<blocks; j++)
      {
        sprintf(buf, "  block %d: ", j);
        Serial.print(buf); 
        pixy.blocks[j].print();
        Serial.println("");
      }
    }
  }
    delay(10);
}