NXT Line Follower (via RobotC)

This time via RobotC (http://www.robotc.net)

const int thresh = 50;      // light sensor thresh
const int power = 40;       // motor power
const int factor = 2;       // multiplicative sweep increase
const int overshoot = 20;   // turn additional after line found
const int initialTurn = 8; // first sweep size

int spin_left(int deg) {
 nSyncedTurnRatio = -100;
 nMotorEncoderTarget[motorA] = deg;
 motor[motorA] = power;
}

int spin_right(int deg) {
 nSyncedTurnRatio = -100;
 nMotorEncoderTarget[motorA] = -deg;
 motor[motorA] = -power;
}

int straight() {
 nSyncedTurnRatio = +100;
 motor[motorA] = power;
}

void stop() {
 motor[motorA] = 0;
}

bool online() {
 return SensorValue(lightSensor) < thresh;
}

void resetMotorEncoder() {
 nMotorEncoder[motorA] = 0;
}

bool stateIdle() {
 return nMotorRunState[motorA] == runStateIdle;
}

task main()
{
 bFloatDuringInactiveMotorPWM = false;
 nSyncedMotors = synchAB;

 int lastDir = 0;
 while (true) {

  while ( online() ) { straight(); }
  stop();

  resetMotorEncoder();
  int turn = initialTurn;
  for ( int i = lastDir; !online(); i++ ) {
   lastDir = i%2;
   for ( int j = turn; j && !online() ; j-- ) {
    if ( lastDir ) { spin_left(1); }
    else { spin_right(1); }
   }
   turn *= factor;
  }

  if ( lastDir ) { spin_left(overshoot); }
  else { spin_right(overshoot); }
  while ( !stateIdle() ) { wait1Msec(1); }

 }
}

transcoding for IPod Touch


$ ffmpeg.exe -y -i INPUT -f mp4 -vcodec libx264 -level 21 -s 480x266 -b 768k -bt 768k -bufsize 2000k -maxrate 768k -g 250 -coder 0 -threads auto -acodec libfaac -ac 2 -ab 128k OUTPUT


I think I used higher audio bitrate. Had to back it off to transcode video off my Olympus camera.

NXT Line Follower

Programmed with the NXT-G (LabView).

Cribbed from http://www.bnxt.com/paper/line_follower

NXT Marble Lift

Trying to figure out the Mindstorms / NXT. Simple robot to save Daniella and I from having to manually move the marbles to the top of the marble run set.