// Ohmmetro V2.2 By Valter & Samuele (Nov. 2007)
#include "NXCDefs.h"

  unsigned long R;                  // value calculated resistance
  int nR;                           // number characters string sR
  string sR;                        // string value resistance
  string s1ohm;                     // string 1 for value resistance ohms
  string s2ohm;                     // string 2 for value resistance ohms
  string s1kohm;                    // string 1 for value resistance Kohms
  string s2kohm;                    // string 2 for value resistance Kohms

/* ---------------------------- SUB sub_ohm --------------------------- */
sub sub_ohm ()
 {
   sR = NumToStr(R);
   nR = StrLen (sR);
   s1ohm = SubStr(sR, 0, nR - 3);
   s2ohm = SubStr(sR, nR - 3 , 3);
   if (nR > 3)
     {
       sR = StrCat(s1ohm,".",s2ohm);
     }
   TextOut(8, 8, " ohm" ,TRUE);
   TextOut(40, 8, sR);
 }

/* ---------------------------- SUB sub_Kohm -------------------------- */
sub sub_Kohm ()
 {
   sR = NumToStr(R);
   nR = StrLen (sR);
   s1kohm = SubStr(sR, 0, nR - 3);
   s2kohm = SubStr(sR, nR - 3 , 1);
   sR = StrCat(s1kohm,",",s2kohm);
   TextOut(8, 24, "Kohm");
   TextOut(40, 24, sR);
 }

/* ---------------------------- START PROGRAM ------------------------- */
task main()
{
  SetSensorType (IN_1, IN_TYPE_SWITCH);    // NXT input 1
  SetSensorMode (IN_1, IN_MODE_RAW);
while(TRUE)
{
  // Calculated: R = (RAW * 10000) / (1023 - RAW)
  R = (SENSOR_1 * 10000)/(1023 - SENSOR_1);
  switch (R)
  {
    case 0 :
      TextOut(20, 16, "(Infinite)",TRUE);  // display infinite if R = 0
      TextOut(6, 8, "Insert Resistor");
    break;
    default :
      sub_ohm();                    // go to sub_ohm
    if (R >= 1000)
      {                             // if value >= 1000 ...
        sub_Kohm();                 // ... go to sub_Kohm
      }
  }

  TextOut(13, 48, "Ohmmetro V2.2");
  TextOut(3, 44, "By Valter & Samu");
  Wait (400);                       // pause 0,4 sec (reading data)
}
}
/* ---------------------------- END PROGRAM -------------------------*/