{$N+}
program Atwood;

uses
    crt,graph,dos;

const
   maxpts = 100;

type
   file_name = string[50];
   data = array [0..maxpts] of real;
   readings = array[0..maxpts] of longint;

Var

   s1, s2 : string;
   ans,ch : char;
   inf, outf : text;
   on, off : readings;
   time, vel : data;
   count : longint;
   ntot,state,state1,state2,invertnum : integer;
   graphdriver,graphmode,midx,midy : integer;
   nx,ny,h,i,j,k,l,maxspins :integer;
   stop           :boolean;
   con1, con2, sumtime, maxxx, maxxy  : real;
   minx,maxx,miny,maxy,
   scalet,scalev :               real;              { for plots }
   timeconst,radius,height,gap : real;                  { initializing }
   a,sumxx,b,sumxy,sumx,sumy,del,delx,dely,temp1,temp2,temp3 : real;
   hour, minute, sec, sec100  : word;
   hour1, minute1, sec1, sec1001  : word;
   ti,tf, newcon2, newcon3, xcount, scon  :real;
   run, runc, check : boolean;
   code : integer;
   v1c,v2c,xa,denom,circum  : real;

procedure takedat;
begin
 writeln('The computer is recording ',ntot,' data points');
 writeln;
 writeln('DO NOT PRESS ANY KEYS OR DATA COLLECTION WILL BE ALTERED !!');
 writeln;
 writeln('After the ', ntot,' times are recorded the data will be ');
 writeln('printed to the screen');
 writeln;
 writeln('If nothing is happening, the computer will automatically');
 writeln('  stop recording the data after 15 seconds');
 writeln;
 runc:=true;

 gettime(hour,minute,sec,sec100);
  for i := 1 to ntot do
      begin
         count := 0;
         run := true;
         while (run and runc) do
         begin
          count := count + 1;
          if port[$201]=240 then run:=false;
          if count>9000000 then runc:=false;
         end;

         off[i] := count;
         count:=0;
         run:=true;

         while (run and runc) do
         begin
          count := count + 1;
          if port[$201]=224 then run:=false;
          if count>9000000 then runc:=false;
         end;
         on[i] := count;
      end;
 gettime(hour1,minute1,sec1,sec1001);

 xcount:=0.0;
 for i:=1 to ntot do
 begin
  xcount:=xcount+off[i]+on[i];
 end;
 ti:=hour*3600.0+minute*60.0+sec+sec100/100.0;
 tf:=hour1*3600.0+minute1*60.0+sec1+sec1001/100.0;
 newcon2:=xcount/(tf-ti);

   writeln (ntot ,' Data points have been taken.');
   writeln;
   for i := 1 to ntot do
        begin
           if on[i]=0 then on[i]:=1;
           vel[i] := con1/on[i];
        end;
   for i:=1 to ntot do
    begin
     sumtime:=0.0;
      for j:=1 to i do
       sumtime:=sumtime + off[j] + on[j];
      time[i]:=sumtime-on[i]/2.0;
      time[i]:=time[i]/con2;
     end;
   writeln('Data point            Time(sec)           Velocity(cm/sec)');
   for i:=1 to ntot do
    writeln('   ',i,'         ',time[i]:16:4,'      ',vel[i]:16:4);
  writeln;
  if (not runc) then
   begin
    writeln('The data is probably bad !!!!!');
    writeln('The photogate might not be working properly');
    writeln('Test the photogate by pressing t');
   end;
end; {takedat}

procedure calbrat;
begin
 writeln;
 writeln('This is the calibration mode to change the time and/or');
 writeln('velocity calibration constants');
 writeln;
 writeln('Enter the number 1, then make the tab block the photogate');
 writeln('5 times.');
 writeln;
 readln(i);
 count:=0;
 gettime(hour,minute,sec,sec100);

 runc:=true;
   for i := 1 to 5 do
      begin
         count := 0;
         run := true;
         while (run and runc) do
         begin
          count := count + 1;
          if port[$201]=240 then run:=false;
          if count>9000000 then runc:=false;
         end;

         off[i] := count;
         count:=0;
         run:=true;

         while (run and runc) do
         begin
          count := count + 1;
          if port[$201]=224 then run:=false;
          if count>9000000 then runc:=false;
         end;
         on[i] := count;
      end;

 gettime(hour1,minute1,sec1,sec1001);

 xcount:=0.0;
 for i:=1 to 5 do
 begin
  xcount:=xcount+off[i]+on[i];
 end;
 ti:=hour*3600.0+minute*60.0+sec+sec100/100.0;
 tf:=hour1*3600.0+minute1*60.0+sec1+sec1001/100.0;
 newcon3:=xcount/(tf-ti);
 writeln('Old calibration constant ',con2:15:2);
 writeln('New calibration constant ',newcon3:15:2);
 writeln;
 writeln('Type in the calibration constant to be saved');
 writeln('(type -1 is you do not want to change the constant');
 readln(scon);
 if (scon>0) then con2:=scon;
 writeln;
 writeln('Enter the factor that you want the acceleration to');
 writeln('increase by:');
 readln(scon);
 con1:=con1*scon;
 writeln('Current circumference distance: ',circum);
 writeln('Type in the new circumference distance');
 readln(circum);
 assign(outf,'c:\calib\cat.dat');
 rewrite(outf);
 writeln(outf,con1);
 writeln(outf,con2);
 writeln(outf,circum);
 close(outf);
 writeln;
 writeln('The calibration is complete, type m to get the menu');
end;

procedure writetofile;
begin
   writeln ('Enter the filename:');
   readln (s1);
   assign(outf,s1);
   rewrite(outf);
   count := 0;
   for i := 1 to ntot do
    writeln (outf,i,'   ',time[i],'   ', vel[i]);
   close(outf);
   writeln('The data has been written: ',ntot,' data points');
end; {writetofile }

procedure read_file;
begin
   writeln ('Which file do you want to read?');
   readln (s1);
   assign(inf,s1);
   reset(inf);
   i:=-1;
   while not EOF(inf) do
    begin
     i:=i+1;
     read(inf,j,time[i+1],vel[i+1]);
    end;
   ntot:=i;
  writeln('The data are: ');
  for i:=1 to ntot do
   writeln(i,'  ',time[i]:16:4,'  ',vel[i]:16:4);
  close(inf);
end;


procedure datview;
begin
 clrscr;
 writeln;
 writeln;
 writeln('The current data are:');
 writeln;
 writeln('Data point            Time(sec)               Velocity(cm/sec)');
 for i:=1 to ntot do
  writeln(i,'              ',time[i]:16:4,'       ',vel[i]:16:4);
 writeln;
 writeln('press m to return to the menu');
end;

procedure rawview;
begin
 clrscr;
 writeln;
 writeln;
 writeln('The raw data are:');
 writeln;
 for i:=1 to ntot do
  begin
   writeln('unblocked counts:  ', off[i]);
   writeln('  blocked counts:  ', on[i]);
  end;
writeln;
writeln(' Press m to return to the menu');
end;


procedure velplot;
begin
  scalet := 1;
  scalev := 1;
  maxxx := 0;
  maxxy := 0;
  for i := 1 to ntot do
   begin
    if time[i] > maxxx then maxxx := time[i];
    if vel[i]  > maxxy then maxxy := vel[i];
   end;
  graphdriver:=detect;
  initgraph(graphdriver,graphmode,'');
  maxx:=getmaxx;
  maxy:=getmaxy;
 setcolor(15);
 line(40,0,40,trunc(maxy-200));
 line(40,trunc(maxy-200),trunc(maxx-40),trunc(maxy-200));
 scalet:=(maxx-80)/maxxx;
 delx:=maxxx/(maxx-80);
 scalev:=(maxy-210)/maxxy;
 dely:=maxxy/(maxy-210);
 setcolor(14);
 for i:=1 to ntot do
  begin
   nx:=trunc(40+time[i]*scalet);
   ny:=trunc(maxy-200-scalev*vel[i]);
   circle(nx,ny,4);
  end;
 sumx := 0.0;
 sumxx := 0.0;
 sumy := 0.0;
 sumxy := 0.0;
 for i := 1 to ntot do
     begin
        sumx := sumx + time[i];
        sumxx := sumxx + time[i]*time[i];
        sumy := sumy + vel[i];
        sumxy := sumxy + time[i]*vel[i];
     end;
 del := ntot*sumxx - sumx*sumx;   { DEL }
 a := (sumxx*sumy-sumx*sumxy)/del;
 b := (ntot*sumxy-sumx*sumy)/del;
 for i:=1 to trunc(maxx-80) do
  begin
   nx:=trunc(40+i*delx*scalet);
   ny:=trunc(maxy-200-scalev*(b*i*delx+a));
   putpixel(nx,ny,10);
  end;

 v1c:=a+b*time[1];
 v2c:=a+b*time[4];
 denom:=v2c*v2c-v1c*v1c;
 if (denom=0) then denom:=1.0;
 xa:=2.0*circum*b/denom;

 setcolor(15);
 str(b:16:4,s1);
 outtextxy(40, trunc(maxy-180),'The slope is ' + s1 + ' cm/sec^2');
 str(a:16:4,s1);
 outtextxy(40, trunc(maxy-170),'The intercept is ' + s1 + ' cm/sec');
 str(xa:8:4,s1);
 str(xa*b:10:4,s2);
 outtextxy(5,trunc(maxy-150),'Constant acceleration calibration check:');
 outtextxy(5,trunc(maxy-140),'scale factor = '+s1+' corrected acceleration = '+s2+' cm/sec^2');
 for i:=1 to ntot do
  begin
   str(time[i]:16:4,s1);
   str(vel[i]:16:4,s2);
   outtextxy(40,trunc(maxy+10*i-130),s1 + '   ' + s2);
  end;

end;


procedure setpoints;
begin
 writeln('Input the number of times the photogate will be blocked');
 writeln('when the holder falls to the ground');
 readln(s1);
 ntot:=4;
 val(s1,ntot,code);
 if (ntot<4) then
  begin
   writeln('You put in an invalid integer');
   writeln('ntot will be set to 4');
   ntot:=4;
  end;
 if (ntot>12) then
  begin
   writeln('You put in an invalid integer');
   writeln('ntot will be set to 12');
   ntot:=12;
  end;
 writeln('press m to get to main menu');
end;

procedure testgate;
begin
writeln('Begin the test');
 for i:=1 to 20 do
  begin
   if (port[$201]=224) then writeln('Un-blocked');
   if (port[$201]=240) then writeln('Blocked');
   delay(10000);
  end;
 writeln('The test is over');
 writeln('type t to repeat the test, m to see the menu');
end;


procedure menu;
begin
      clrscr;
      writeln(ntot,'  data points will be taken');
      writeln ('What would you like to do? ');
      writeln;
      writeln ('*****************************');
      writeln ('* Set the number of data points taken:  n  *');
      writeln ('* take data:                            d  *');
      writeln ('* plot v vs t:                          g  *');
      writeln;
      writeln ('* View the data:                        v  *');
      writeln ('* View the raw data from computer       r  *');
      writeln ('* To see the menu:                      m  *');
      writeln ('* Test the photogate:                   t  *');
      writeln ('* Quit:                                 q  *');
      writeln ('*****************************');
end;

begin {main}
   clrscr;
   writeln;
   writeln;
   writeln;
   writeln('                     Atwood Machine Program');
   writeln;
   writeln;
   writeln('       by Rich Aguayo (Cal Poly Pomona Physics graduate 91)');
   writeln;
   writeln('          Joe Kobayashi (Cal Poly Pomona Physics graduate 99');
   writeln;
   writeln('          and Mark Harnetiaux (Cal Poly Pomona Physics Technician');
   writeln;
   writeln;
   writeln('   press enter to get menu');
   ntot:=4;
   for i:=1 to 100 do
    begin
     time[i]:=i;
     vel[i]:=i;
    end;
   readln;
   menu;
{   con1:=740000.0;
   con2:=660000.0;   }
   assign(inf,'c:\calib\cat.dat');
   reset(inf);
   readln(inf,con1);
   readln(inf,con2);
   readln(inf,circum);
   close(inf);
   stop:=false;
   repeat
    if keypressed then
     begin
      case readkey of
       'n','N' : begin
              closegraph;
              setpoints;
             end;
       'd','D' : begin
              closegraph;
              takedat;
             end;
  {     'w' : begin
              closegraph;
              writetofile;
             end;
       'r' : begin;
              closegraph;
              read_file;
             end;    }
       'g','G' : begin
              closegraph;
              velplot;
             end;
       'v','V' : begin
              closegraph;
              datview;
             end;
       'r','R' : begin
              closegraph;
              rawview;
             end;

       't','T' : begin
              closegraph;
              testgate;
             end;
       'm','M' : begin
              closegraph;
              menu;
             end;
       'Z' : begin
              closegraph;
              calbrat;
             end;
       'q', 'Q'  : begin
                    closegraph;
                    stop:=true;
                   end;
      end; {case}
     end;{if}
   until stop;
clrscr;
end.