St Margaret College Secondary School Verdala. Smart Wheelchair. Form 3 NXT Coursework Project. Marquita Formosa (Class X)

Transcription

1 St Margaret College Secondary School Verdala Smart Wheelchair Marquita Formosa (Class X)

2 Marking Scheme (This was given to you during the Computing lesson) Marquita Formosa Page 2

3 Table of Contents Marking Scheme... 2 Table of Contents... 3 Section 1 Problem Definition... 4 Robot capabilities... 4 Real life application... 4 Section 2 I/O Device Requirements... 5 Input Devices... 5 Output Devices... 5 Section 3 Algorithm Design... 6 Section 4 Program Printout... 8 Section 5 Evidence of solution Section 6 Evaluation Limitations Improvements Marquita Formosa Page 3

4 Section 1 Problem Definition Robot capabilities This robot is programmed to move forward until a sound is detected through the use of the sound sensor. Following that, the user needs to press the Enter button (the orange centre button). Depending in which direction the user requires the robot to turn, the user can choose to press either the left or right touch sensor to instruct the robot accordingly. The user can release the touch sensor once the robot has turned enough. As soon as the touch sensor is released the robot stops turning and starts moving forward once again. This process is repeated indefinitely. Real life application This robot can be used as a smart wheelchair in which the user can determine the direction in which he wants to go without any extra effort. Once switched on, the wheelchair will start moving forward and stops until the user tells it to. Subsequently the user can choose the direction in which he/she wants to turn and continue moving forward until instructed by voice to stop again. Marquita Formosa Page 4

5 Section 2 I/O Device Requirements Input Devices 1. Sound Sensor Use: To detect sound made by the user in order to stop the robot Touch Sensors Use: To indicate the direction of movement, one to turn left and one to turn right. 3. NXT Buttons - Middle (orange) button Use: To start moving again. Output Devices 4. Speaker Use: To output Right sound and Left sound Motors Use: To move the robot. Marquita Formosa Page 5

6 Section 3 Algorithm Design Marquita Formosa Page 6

7 Marquita Formosa Page 7

8 Section 4 Program Printout Figure A Sequence and Iterations 1, 2 and 3 Marquita Formosa Page 8

9 Figure B - Decisions 1 and 2 Marquita Formosa Page 9

10 Section 5 Evidence of solution Figure C: Robot representing Smart Wheelchair Figure E: Robot turning right by pressing the right touch sensor Figure D: Robot turning left by pressing the left touch sensor Marquita Formosa Page 10

11 Section 6 Evaluation Limitations 1. If the user falls asleep while the wheelchair is moving, it will continue moving forward without stopping, with the risk of hitting any object in its path. 2. The wheelchair will not detect any varying levels of ground it is moving on and which can therefore cause it to fall over if there are any downward steps. 3. If there is additional background noise, the robot might detect this sound (if > 100dB) and considers it as an instruction to stop, while its user wants it to continue moving forward. Improvements Improvements for the above Limitations: 1. An ultrasonic sensor taking horizontal readings can be added to the wheelchair so that the robot can detect that there are oncoming objects and stops even though the user doesn t instruct to. 2. Another ultrasonic sensor taking vertical readings can be added to constantly read the distance from the robot to the floor so that if there is a drop in the ground, e.g. downward stairs, the ultrasonic sensor detects the increase in distance and stops the wheelchair immediately. 3. Voice recognition can be introduced in order to identify the user s voice instructions from any other background noise. Additional Functions: A GPS can be installed on the wheelchair (if being used outside) so as to be able to help the user to arrive from one place to the other with thorough road guidance. Marquita Formosa Page 11