Overview

This robot is able to trace out the boundaries of a surrounding, for example, the walls and output the map onto a computer.

Setup

Boards and Sensors

• Arduino Uno.
• Ultrasonic Sonic Sensor HC-SR04.
  • Sensor 1, 2 and 3 is on port, front, starboard side respectively.
• Arduino Motor Shield similar to model (L293) (SKU: DRI0001) with no brake control.
  • Motor A and B is on port and starboard side respectively.
• Wheel Encoders (SKU: SEN0038).
  • Encoder A and B is attached to motor A and B respectively.

Software

• Arduino IDE

Deployment

1. Connect to computer and long press the pushbutton to initiate and reset the map in EEPROM.
2. Place arduino car near a boundary.
3. Switch on the Arduino board and the motors.
4. Long press the pushbutton to begin mapping.
5. Press pushbutton when arduino car is moving in a straight line after mapping is completed.
6. Connect to computer to obtain map via EEPROM.

Below is a video of the robot in action.

Results

'0' indicates free space while '1' indicates boundaries.

Mechanism

Moving

This robot is following the boundaries using left-hand rule.

• Is obstacle in front?
  • Yes: Turn right
  • No: Proceed checking
• Is there free space at the left?
  • Yes: Turn left
  • No: Move forward at a distance from the boundaries at the left

Mapping

• Look up the direction the robot is facing via dead reckoning (North, South, East, West)
  • If robot turn left: change internal direction towards left (i.e. North to West)
  • If robot turn right: change internal direction towards right (i.e. North to East)
  • If robot move forward: change '0' to '1' in previous position