TSL1401 Line Sensor

Základom kamery je lineárne senzorové pole 128x1 doplnené o vzorkovací obvod. Funkcia je popísaná v datasheete. Kamera okrem toho obsahuje oddelovací zosilňovač, ktorého schéma zapojenia je tu:

Dokumenty:

• Datasheet

Úlohy

1. Určte ohniskovú vzdialenosť objektívu
2. Určte vzdialenosť kamery od 3cm pásiku, aby sa premietol na celý čip.
3. Pomocou osciloskopu a čierneho pásiku zaostrite kameru
4. Zistite vplyv osvetlenia zadnej steny čipu na kvalitu obrazu
5. Pripojte kameru k PC a pomocou demonštračného programu zosnímajte jednoduchý čiarový kód
6. Pozrite si zároveň aj signál na osciloskope (uložte na USB klúč)
7. Zistite vplyv zmeny expozičnej doby na kvalitu snímky
8. Zosnímajte predložený čiarový kód.
9. Záznam z každej úlohy vypracujte vo forme technickej správy.

/* ************************************************************ */                              
/* Cvicenie so snimacom TSL1401 -- riadkovy CMOS snimac 128px   */
/*                                                              */
/* ************************************************************ */                              

                     // Sensor interface: 
#define AOpin  0     // Analog output - yellow
#define SIpin  3     // Start Integration - orange
#define CLKpin 2     // Clock - red
                     // Vcc - brown
                     // GND - black

#define NPIXELS 128  // No. of pixels in array

byte Pixel[NPIXELS]; // Field for measured values <0-255>


#define FASTADC 1   
 // defines for setting and clearing register bits
 #define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
 #define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))



void setup(void)
{
   pinMode(SIpin, OUTPUT);
   pinMode(CLKpin, OUTPUT);
   //pinMode (AOpin, INPUT);

   digitalWrite(SIpin, LOW);   // IDLE state
   digitalWrite(CLKpin, LOW);  // IDLE state

#if FASTADC
  // set prescale to 16
  sbi(ADCSRA,ADPS2);
  cbi(ADCSRA,ADPS1);
  cbi(ADCSRA,ADPS0);
#endif

   Serial.begin (115200);
}



void loop (void)
{
   int i;
   int expTime;


   delayMicroseconds (1);  /* Integration time in microseconds */
   delay(10);              /* Integration time in miliseconds  */


   digitalWrite (CLKpin, LOW);
   digitalWrite (SIpin, HIGH);
   digitalWrite (CLKpin, HIGH);
   digitalWrite (SIpin, LOW);

   delayMicroseconds (1);            

/* and now read the real image */

   for (i = 0; i < NPIXELS; i++) {
     Pixel[i] = analogRead (AOpin)/4 ; // 8-bit is enough
     digitalWrite (CLKpin, LOW);
     delayMicroseconds (1);
     digitalWrite (CLKpin, HIGH);
   }


   Serial.write ((byte)0);            // sync byte = 0
   for (i = 0; i < NPIXELS; i++) {
       Serial.write ((byte)Pixel[i]+1);  

   }
}

Posledný zdroják je vizualizačný program pre Processing.org

/* LineViewer --- display for Arduino image sensor 2010-08-01 */

import processing.serial.*;

final int LINELEN = 128;
final int SCROLLHT = 128;
PImage img;
Serial duino;
boolean Synced = false;

void setup ()
{
   println ("<START>");
   println (Serial.list());
   println ("<END>");

   // Open serial port to Arduino at 115200 baud
   duino = new Serial (this, Serial.list()[3], 115200);

   // Window is same width as sensor, but long enough to scroll
   size (LINELEN, SCROLLHT);

   // Image is same size as window
   img = createImage (LINELEN, SCROLLHT, RGB);

   // Initialise image to a shade of blue
   img.loadPixels ();

   for (int i = 0; i < img.pixels.length; i++) {
     img.pixels[i] = color (0, 90, 102);
   }

   img.updatePixels ();

   // Choose image update rate
   frameRate (30);
}

void draw ()
{
   int i;
   int ch;
   int nbufs;
   int b;
   int maxi;
   int maxpx;
   int mini;
   int minpx;
   byte[] inbuf = new byte[LINELEN + 1];

   // Synchronise
   if (Synced) {
     nbufs = duino.available () / (LINELEN + 1);
   }
   else {
     do {
       while (duino.available () == 0)
         ;

       ch = duino.read ();

     } while (ch != 0);
     nbufs = 0;
     Synced = true;
   }

   // Load the image pixels in preparation for next row(s)
   img.loadPixels ();

   for (b = 0; b < nbufs; b++) {
     // Scroll the old image data down the window
     for (i = img.pixels.length - LINELEN - 1; i >= 0; i--) {
       img.pixels[i + LINELEN] = img.pixels[i];
     }

     // Read 128 pixels from image sensor, via Arduino
     duino.readBytes (inbuf);

     // Check we're still in sync
     if (inbuf[128] != 0) {
       print ("UNSYNC ");
       Synced = false;
     }

     maxi = 0;
     maxpx = 0;

     mini = 0;
     minpx = 255;

     // Transfer incoming pixels to image
     for (i = 0; i < LINELEN; i++) {
       ch = inbuf[i];
       if (ch < 0)
         ch += 256;

       if (ch > maxpx) {   // Look for brightest pixel
         maxi = i;
         maxpx = ch;
       }
  
      if (ch < minpx) {   // Look for brightest pixel
         mini = i;
         minpx = ch;
       }

       img.pixels[i] = color (ch, ch, ch);
     }

     img.pixels[maxi] = color (0, 255, 0); // Mark brightest in green
     img.pixels[mini] = color (255, 0, 0); // Mark darkest in red
   }

   // We're done updating the image, so re-display it
   img.updatePixels ();
   image (img, 0, 0);
}