NQC Code to alow a Lego RCX brick to stand on two wheels. I place this code in the public domain. No rights reserved.

gistfile1.txt

#define FULL_POWER_OFFSET 3


task main()
{
   SetSensor(SENSOR_2,SENSOR_LIGHT);
   int last_reading=SENSOR_2;
   
   //start adjust_power;
   SetPower(OUT_A+OUT_C,7);
   
   while (true) {
       if (SENSOR_2 > last_reading){
        OnFwd(OUT_A+OUT_C);
        Wait(0);
        if (SENSOR_2-last_reading>FULL_POWER_OFFSET){
         //OnFwd(OUT_A+OUT_C);
         until(SENSOR_2<=last_reading+FULL_POWER_OFFSET);
         OnRev(OUT_C+OUT_A);
         Wait(0);
         Off(OUT_A+OUT_C);
        }
        Off(OUT_A+OUT_C);
        Wait(0);
       }
       if (SENSOR_2 < last_reading){
        OnRev(OUT_C+OUT_A);
        Wait(0);
        if (last_reading-SENSOR_2>FULL_POWER_OFFSET){
         //OnRev(OUT_C+OUT_A);
         until(SENSOR_2>=last_reading-FULL_POWER_OFFSET);
         OnFwd(OUT_C+OUT_A);
         Wait(0);
         Off(OUT_A+OUT_C);
        }
        Off(OUT_A+OUT_C);
        Wait(0);
       }

  }
}