Nature of the Problem / Project Goal

The nature of the problem that we have been given is to construct a PIC buggy that is able to navigate itself around a maze, only using two clicker inputs physically attached to it. The buggy needs to be adaptive to its surroundings; it can not have a pre-programmed route within its memory, as the maze can change. The goal of the assignment is to allow the buggy to navigate the maze and play a sound at a stage of its journey around the maze. The project also allows the group members to gain a better understanding of the software language (customized version of BASIC) and to develop better team interaction skills.

Detailed Design

Resources

We have been provided with:

•	PIC Buggy kit (semi-assembled)
•	Computer buggy interface (serial cable)
•	Programming software PICAXE

Our group has supplied additional resources such as additional batteries of higher quality in order to allow extended testing of the buggy during construction stages.

The PIC buggy contains LED lights, piezo speaker, two 3-12V DC motors and the pre-constructed PCB partially completed. Flash memory has been placed onto the buggy in order to store the program that the buggy will execute when turned on. The buggy is able to understand the PICAXE program which uses a customized version of BASIC in order to send electronic signals to the motors, lights and speakers. The software used is also able to use inputs from two ‘clickers’ that are mounted on the front of the buggy.

Construction

The project did not have to be started from scratch. Our group was aided by the buggy presented as a kit form, the etching of the PCB of the tracks and the difficult soldering were done at the time of purchase. The construction that the group had to do was relatively simple and within the scope of the assignment. Team members needed to learn how to solder, where some had previous soldering experience and was able to solder the critical parts on in minimum amount of time. The soldering constituted of attaching two 3-12V DC motors onto the buggy and attaching a wheel to either motor to propel the buggy around the maze. The piezo speaker and the LED lights were already soldered onto the buggy beforehand. Two ‘clicker’ inputs were also screwed on to the two front corners, with 3 wires being soldered onto each. These wires were then soldered onto specific contact points on the buggy as specified in the instruction manual. Four zero-ohm links were then soldered onto the motors, two onto each motor.

The flash memory, an on/off switch, various resistors and the battery holder/contacts were pre-assembled when we were given the buggy kit. A 3.5mm jack was also soldered onto the rear of the buggy during pre-assembly in order to interface the buggy with a PC via a cable, so the flash memory could be altered and a program to be run.