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Conference 7.286::atarist

Title:Atari ST, TT, & Falcon
Notice:Please read note 1.0 and its replies before posting!
Moderator:FUNYET::ANDERSON
Created:Mon Apr 04 1988
Last Modified:Tue May 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1433
Total number of notes:10312

125.0. "Do it yourself scanner" by MILRAT::WALLACE () Tue Jun 14 1988 21:44

T.RTitleUserPersonal
Name
DateLines
125.1The scheme of the scanner (I've not tested it)HLDG02::VELZENThu Jun 16 1988 11:3459
  NE555 is wired as a monoflop if pin 2 (trigger) is made low, pin 3 gets high
The time pin 3 stays high depents on the time it takes to charge the capacitor
If pin 6+7 are at a high potential the charching time will be short.
If the potential at pin 6+7 is low the charching time will be long. 



   +5V -----+-----------------------+------+--------------+ +5V (from joy-stick)
            |                       |      |              | 
            \ 10K                   |      |              |
            /                       |      \ 500 K        \ PHOTO TRANSISTOR
            \                       |      / <--+          \ 
            /                       |      \    |           |   <-----LIGHT
            |          +--------+   |      /    |          /    <-----
            |      +---|        |---+      |    |         /< 
            |      |   | NE555  |          |    |         |  
    RTS ----+----------|        |---+------+----+---------+
                   |   |        |   |      |
    DCD ---------------|        |---+      |  
   (RS-232)        |   |        |          |
                   |  -|        |-       -----
                   |   +--------+        ----- 10 NF
                   |                       |
                   |                       |
      -------------+----------------------------- 0 V

RTS (pin 4 on RS-232 port) starts conversion

DCD (pin 8 on RS-232 port) is the output of this scheme


This routine should read in the time DCD stays high after RTS is made LOW

       MOVE,W   SR,-(A7)   ;STORE SR 
       MOVE,W   #$2700,SR  ;NO INTERRUPTS

       CLR,W    D0
       MOVE,B   #14,$FF8800 ;SELECT PSG PORT A      (PSG??)
       ORI,B    #40,$FF8802 ;MAKE RTS LOW
       ANDI,B   #$F7,$FF8802 ;MAKE RTS HIGH AGAIN
 
LOOP: ADDQ,W    #1,D0      ;DO+1 
      BTST      #1,$FFA01  ;DCD STILL HIGH ? 
      BNE       LOOP       ;

      MOVE,W    +(A7),SR   ;INTERUPTS AGAIN
      RTS                  ;READY   
  
THE RESULT OF THE ROUTINE IS FOUND IN D0 (8-bit)

The article says that a complete scan-program can be purchased for f 59
this is about $35.


Excuses for this messy note, I haven't got too much time to type this in
(haven't got a modem)


           Jan-Willem
125.2Another one, with free software this timeHLDG02::VELZENFri Jun 17 1988 14:0610
    Just picked up the May issue of ST (a german magazine)
    
    It has a scheme of a scanner (cost about $ 20 ) and a complete listing
    of a gfa basic program (PD) which reads in the picture, changes
    the gray-scale (it's for black and white only) etc.
    The scanner (which is also mounted on top of a printer-head) is
    connected to the joystick-port.
    
                 Jan-Willem 
    
125.3Oops: April not MayHLDG02::VELZENMon Jun 20 1988 09:495
    It's not the May issue but the april issue.
    It also has a joke, running the CPU at 10 Mhz, chancing a register.
    That article is dated 1-april-88.
    
                Jan-Willem
125.4Still aching in the fingers ..PILOU::ANDERSENRelocating my way home ?Mon Jun 20 1988 11:395
125.5Real or Imaged?RDGENG::KEANEMon Jun 20 1988 12:1342
              
              
    Hi, Jan-Wellem and Martin,
              
      	      	I dont understand why you are disheartened by the "April
    fool's joke"?.- There are a number of "electronics" companies selling
    scanners that fit on printers just as you describe. I am sure that
    the electronics in the scanner is as crude as your examples !! For
    that these firms change around 150 pound sterling!.  
        What would be a nice design for a scanner would be to incorporate
    some form of CCD Image cell, which could scan several rows of pixals
    of the subject material in one pass of the printer head. The printer 
    could then advance the picture by a reasonable amount each row. It
    might be neccessary to provide some form of averaging program, to look 
    at the top row of the last scan, and the bottom row of the current scan
    and average or dither any differences away, to hide the joins.
    	I have seen these IC cells advertised in the past, and have
    had a look through the old mags and pricebooks I have, but cant
    find any adverts for them at the moment. Does anyone know roughly
    how many cells these devices hold, and how much are they? Can the
    CCD cell be used in "linear" mode?
    	The other interesting thought on scanners, is the diference
    between a crude on/off white black scanner, and a true grey scale
    device. If I remember my optics course at college, colour or grey
    scale luminance is a square law, so some form of log amp is neccessary
    to convert the output of a photo sensor and produce a reasonable
    scale. you would then need a a-d and input interface.  
        There are two objectives, either to produce a picture suitable for
    direct viewing on a high, med or low res screen, or to produce and
    store an image for use with a very high res output medium >300 DPI
    printer.       
    	Are there many people interested in imaging???, I am interested,
    and will be investigating further, when I finish my hard disk, (nearly
    there now), I have had a bit of finger trouble on my part, my stupidity,
    with power supplies, but I am slowly winning, soldering iron in         
    hand, whenever my wife allows me into the house from performing         
    the outside chores!!                                                    
    	         
    Keep cheerful!
          
    Pat K.                 
                   
125.6No April joke at allHLDG02::VELZENMon Jun 20 1988 15:2423
    Lest get some things straight.
    
    1) The april joke was running the cpu at 10 Mhz by setting a bit
    in a secret register, it has nothing to do with the scanner's.
    
    2) The first scanner (with the NE555) is real
    
    3) The second scanner (with PD GFA-basic program) is also real.
    
    My mistake to change May and April has nothing to do with the scanner.
    
    Unfortunately I haven't got the time yet to test the second scanner
    (I haven't programmed anything on the ST yet, so the second scanner
     will work within less time), but when I'm leaving DEC (end of my
    practical assignment) my hollidays start, so then I'll grap my
    soldering iron and build those scanners.
    
    If anyone is interested I can send them the article of the second
    scanner, (remember it's in german).   
    
       Jan-Willem           
    
    
125.7Grey ScalesDORIS::JAMESHoward James/PSG Tech Support/Queens HouseWed Jun 22 1988 08:198
125.8Atari + nice projektsHLDG02::VELZENWed Jun 22 1988 11:2514
    Ha, another self-build topic, waiting for me !
    
    Some time ago there was a scheme and software for a weather satelitte
    decoder for the ST at usenet.
    It produced pictures in DEGAS or in AIM format.
    
    So now there is also activity for slow scan television.
    Is this slow scan from shortwave?
    How large is your decoder hardware?
    What's the adress for the software?
    Is this software for color only ? (I hope not)
    
                      Jan-Willem
    
125.9More SSTV info.DORIS::JAMESLeft Handed People are Super NaturalFri Jun 24 1988 12:0416
    Jan Willem - Yes the slow scan is on short wave at around about
    14.230 Mhz. You really need a SSB receiver to tune the sync pulses
    at 1.2 Khz, Black video at 1.5 Khz and white video at 2.3 Khz. Take
    the output from the speaker and convert it to RS232 level to drive
    the CTS (pin 5) of the 25 way serial port on the ST.
      The software is available from J&P Electronics Ltd., New Road
    Complex, New Road, Kidderminster, DY10 1AL, England. Sorry to tell
    you this but it is for LO RES only. That company can also provide
    a lead and level converter so you don't really have to build anything
    if you're that way inclined. Their tel. no. is 0562-753893 (leave
    the 0 off if dialling outside England.
       I am working on sample & hold, F-D and D-A to do the conversion
    and drive the printer port. I'm afraid it will be the software that
    will hold me up though.
      Happy scanning....
    ...Howard
125.10STAD Manual tecnical info needed .PILOU::ANDERSENRelocating my way home ?Wed Jun 29 1988 13:1013