[Gdeaver]

In Easy C I found there is some latency with the encoder value assignment. In other words there probably will be a couple of clicks between a right and left read. Alternate the encode read oder to compensate. With the sonar sensor you get the time for the first returned wave. To cover a larger area and gather more info on the robot world mount the sonar sensor on a servo and read step read step thru the servo's range. This works very well for IR sensors. You can differentiate between a furniture leg and a wall.