Learning   Examples | Foundations | Hacking | Links

Examples > Robot

Rescue

The Rescue challenge in robotics consists of getting your robot to follow a line until it reaches a location where it will perform a task. In this case, the robot makes it to an obstacle, pushes it out of the way, and continues along.

Hardware Required

  • Arduino Robot
  • Large paper
  • Thick black marker
  • Obstacles, like empty cans, or not too-heavy toys
  • "victim" objects

Instruction

  1. To prepare the track, follow the instructions in line following example. There are a few differences:
    1. Add some end lines for the robot to stop. Create a gap in the line, and draw a rectangle about the size of the robot in the gap.
    2. Put the "victim" object inside the rectangle.
  2. Upload the example, unplug USB and turn on power.
  3. Put robot on the track, on the line.
  4. The robot will start following the line, and push the victim out of its location
  5. If the robot does not follow the line well, see lineFollowConfig() for details on calibration.

Try it out

First, draw your racing track, adding the stops (perpendicular lines) for the robot to know where the obstacles will be.

Use a marker to design your racing track

Place your obstacles on the track. The robot can push some weight, like empty soda cans or small plastic toys make for good obstacles.

Place the obstacles

Put the robot on the track and turn it on to see if it can solve the challenge.

Put the robot to run

In front of an obstacle, the robot slows down, starts pushing the object, backs up and starts racing again.

Robot pushing the obstacle away

Code

/* Robot Rescue

 In this example, the robot enters the line following mode and
 plays some music until it reaches its target. Once it finds the
 target, it pushes it out of the track. It then returns to the
 track and looks for a second target.

 You can make the robot push as many objects as you want to, just
 add more to calls to the rescue function or even move that code
 into the loop.

 Circuit:
 * Arduino Robot
 * some objects for the robot to push
 * a line-following circuit

 created 1 May 2013
 by X. Yang
 modified 12 May 2013
 by D. Cuartielles
 
 This example is in the public domain
 */


#include <ArduinoRobot.h> // include the robot library
#include <Wire.h>
#include <SPI.h>

void setup(){
  // initialize the Robot, SD card, display, and speaker
  Robot.begin();
  Robot.beginTFT();
  Robot.beginSD();
  Robot.beginSpeaker();
 
  // draw "lg0.bmp" and "lg1.bmp" on the screen
  Robot.displayLogos();

  // display the line following instructional image from the SD card
  Robot.drawBMP("lf.bmp", 0, 0);

  // play the chase music file
  Robot.playFile("chase.sqm");

  // add the instructions
  Robot.text("Rescue\n\n place the robot on\n the rescue track\n pushing the\n obstacles away", 5, 5);
  Robot.text("Press the middle\n button to start...", 5, 61);
  Robot.waitContinue();

  // start
  Robot.fill(255, 255, 255);
  Robot.stroke(255, 255, 255);
  Robot.rect(0, 0, 128, 80); // erase the previous text
  Robot.stroke(0, 0, 0);
  Robot.text("Start", 5, 5);
 
  // use this to calibrate the line following algorithm
  // uncomment one or the other to see the different behaviors of the robot
  // Robot.lineFollowConfig(11, 5, 50, 10);
  Robot.lineFollowConfig(11, 7, 60, 5);
 
  // run the rescue sequence  
  rescueSequence();
  // find the track again
  goToNext();
  // run the rescue sequence a second time
  rescueSequence();
 
  // here you could go on ...
 
 
}

void loop(){
  //nothing here, the program only runs once.
}

// run the sequence
void rescueSequence(){
  //set the motor board into line-follow mode
  Robot.setMode(MODE_LINE_FOLLOW);  
 
  while(!Robot.isActionDone()){  // wait until it is no longer following the line
  }
  delay(1000);

  // do the rescue operation
  doRescue();
  delay(1000);
}

void doRescue(){
  // Reached the endline, engage the target
  Robot.motorsWrite(200,200);
  delay(250);
  Robot.motorsStop();
  delay(1000);

  // Turn the robot
  Robot.turn(90);
  Robot.motorsStop();
  delay(1000);
 
  // Move forward
  Robot.motorsWrite(200,200);
  delay(500);
  Robot.motorsStop();
  delay(1000);
 
  // move backwards, leave the target
  Robot.motorsWrite(-200,-200);
  delay(500);
  Robot.motorsStop();
}

void goToNext(){
  // Turn the robot
  Robot.turn(-90);
  Robot.motorsStop();
  delay(1000);
}

See Also:

Share