This is my second robotics project. It is an Arduino controlled obstacle avoidance robot. It uses an SDM-IO ultrasonic range finder to detect objects in or near its path. It continually scans its environment and emits a tone that is dependent on the distance. If an object gets too close, the robot will veer away and sound an alarm and if an object gets too close then the robot will pivot away from the object and sound a different alarm.
Here is the initial test of the sensor. It continuously scanned the area in a broad range and taking readings in small increments. There was a lot of noise which resulted in false low readings and caused the robot to react unpredictably. The tone and noises are interesting. Now the robot scans at five different places and takes the average of three readings.