Quote:
Originally Posted by barstow
We put the vex ultrasonic sensor on our bot for some tests,
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Well, we tried the vex ultrasonics once and never had a whole lot of success with them. As i mentioned above, and as is mentioned just above this post, the Parallax PING))) sensor is a very robust option.
Round (cylindrical, parabolic, spherical) objects can be viewed from any angle since the wave from the ultrasonic sensor (which is a section of a sphere in shape) can find a perfect tangent point from any angle to the round object. For example, if you wanted to... say... find a pipe... (have no idea why you want to do that
) it looks the same from any side (since there aren't really any sides to a circular surface).
What you say is true for flat objects. Within a narrow margin of off-axis, ultrasonics measure fine. But as you go off axis your measurements are distorted then soon disappear. That's we use a number of different schemes of data processing/collection from multiple ultrasonic sensors depending on the situation to get reliable data (this lead to the development of the aforementioned quad-ultrasonic driver) As a hint, one of these incudes mounting the ultrasonic sensor on an airplane servo.
Questions, Post!
-q