[Tom Line]

The beam width on a sonar sensor is a function of the sensor. You could try to put a tube around the emitter - even a piece of paper might work to start with, but I wouldn't hold out high hopes.

The dowel listed in the manual is used to show the sensor's capabilities. Read the beam characteristics section.

We've used the maxbotics in the past, and we stay away unless we have a large, flat surface to reflect from. Even the vertical tubes in 2011 sometimes bounced a signal back at 10-15 feet and introduced too much variability to use the sensor consistently.