Hi, I am from South Africa and I love robotics . I am seventeen years old and this is my second robot My goal was to make an autonomous mobile platform which can traverse an area using dead-reckoning or infrared obstacle avoidance backed up by bump switches. This platform had to give a user friendly interface with the help of hyper-terminal and had to be easily configurable through hyper-terminal. MICROCONTROLLER BOARD The microcontroller is the heart of any little robot. It takes the readings from all the sensors processes it and decides on the course of action. Initially I started off with a motorola mc68hc908gp32. It was a very powerful processor but I found that it seemed to be very susceptible to noise. Anyhow I did not need the processing power that this microcontroller offered . It had a maiximum internal bus speed of 8Mhz and 32 Kilobytes of program space . I then changed the robot`s microcontroller to a pic16f876/20p which was made by microchip . It ran at a maximum of 5Mhz internally and had 8Kb of program space with 14 interrupt sources. I found that noise did not easily interfere with this microcontroller. This microcontrolller came in a 28 pin shrink package with many peripherals which are needed by this robot such as PWM , Analog to digital converter and a serial port . SENSORS : wheel encoders infra red avoidance bump switches light level sensors CHASSIS : perspex disc MOTORS: hacked servo motors with encoders FUNCTIONS: This little robot can: 1 Avoid obstacles (infra red avoidance and micro switches) 2 Seek for light 3 Run a pre-programmed route PROBLEMS: The main problem I had was getting the encoders to work properly. Firstly the light interferred with it, secondly it was hard to align the wheel encoder discs so they would not skip pulses. Therefore i went for internal encoders. TIME AND COST : Time about 6 months Cost about r400 but had alot of the parts lying around FOR MORE INFO: THE ROBOT 876 SITE http://users.iafrica.com/m/mw/mwjparso/robot876.htm MY HOMEPAGE WHICH LINKS TO ROBOT876 SITE http://users.iafrica.com/m/mw/mwjparso/homepage.htm Email: mwjparso@iafrica.com