BigWheel is my first build robot. It is bassed on an mini 552 procesoor board. The motors are driven through a LM298N The IO is with I2C - PCF 8574. Its chassis is of aluminium which I glued together, after gueing I put it in an oven and now the glued parts are stronger then the aluminium. In this way it was easy to build. The used sensors are switches for contact to obstacles, and the ISF471 for nearby obstacles. It can find its way through al kind of obstacles. But thats a part of the software. I programmed it in C++ The problems i encountered where: In the beginning i drived one wheel left and one wheel right. When the floor was not even i had problems from comming away. I have solved that by connecting both left wheels and both right wheels through a chain. Now it is a strong one. A problem i still have to solve is the slip of the wheels which make a powerfull start neccessary. Probably hard tires will solve that problem For more information see my website: http://www.robot.buiskool.net/modules.php?name=ROBOT Look at projecten and find there my other projects. It's a complete Dutch site but schematics and pictures are international. I hope to see you. Email: robot@buiskool.net