UPDATE: This project has finally been scrapped :(
I have made the decision to build this robot as part of my Degree 3rd year project; at this present time the actual competition is canceled although there is a slight possibility that it will be put on again, I have currently made most of the robot but I haven't finished the sensors or programmed it yet. Because of the type of person i am and as there is no competition to look forward to I have no motivation to finish it, this is why I am planning to do it as part of my project, that way I will be forced to finish it. At the time of writing this (06/05/05) I haven't discussed this project with any of my lectures so there is the possibility that I won't be able to do it, in which case it will probably never get finished.
The Robot
Unlike the previous robot for the melexis competition this robot was going to be very clever, not clever clever as in intelligent but clever as it will use lots of sensors and hopefully a very well written program.
Motor Controller
The previous robot used heavy duty relays to control the motors, these switched the motors on or off there was no in between, the second problem then arose with the supply voltage, the batteries were 6v but the motors were rated at a lower voltage, to fix this problem i used a 100w resistor in series, this was very crude got very very hot and wasted a lot of energy.
The aim this with this robot is to use PWM to control the motors, this way supply voltage wont be a problem and the speed can be controlled.
Sensors
The previous robot used 5 proximity sensors on the front and 1 proximity sensor on the top as well as a compass for basic direction finding, this meant that it couldn't detect the difference between the hot and cold cans or the flashing beacon.
This competition requires the detection of all the obstacles obstacles otherwise the robot wont finish and wont win.
Micro controllers
The only suitable programming language I know is assembler for the PIC micro controller, I also have a programmer and debugger for the PIC 16F877, this reduced the micro controller choices to 1 device, the 16F877!
The problem with this device is the limited number of inputs as well as the overall problem with most chips, code is only executed 1 line at a time. To overcome both these problems I have made the decision to use multiple chips, one for the sensors, one for the sign detector sensor, one for the motors one for the lights (explained below) and one to control the others.
These the sensor chips will feed data to the master chip this will then decide what to do and control the motor and light chip.
Peripheral Features (Lights)
One of the requirements of the root was that it indicated left or right when it had decided on what sign it was at, as usual I have decided to go one step further and include in addition to the indicator lights, full beam head lights, side lights, reverse lights and break lights. These will all be controlled from there own PIC, the hazard lights and the headlights can also be turned on from on board switches as well as instructions received from the main chip.
You can use the links below to take you to different pages each explaining the different stages.
As I am planning to do this for my degree project everything will need to be documented, I am planning to including most of this here.