Ultrasonic Refraction Issue

Drohn

When the ultra sonic is at an angle with a wall, (as shown) and should be still hitting it, it seems to get an obstacle farther down the way. This seems to happen some at angles starting at 60 degrees. See the image below. I think the issue is the waves are bouncing as seen. By the way, when the US should be giving back 48, it's giving back 69, which is the distance to the other obstacle.

The green lines represent the wave being sent out, and the orange represents the one returning. The grey lines are showing the distances. The lines on that paper, are also about one centimeter apart from each other.

Chris Savage

Drohn,

The results you’re getting are exactly as should be expected. The waves will actually bounce differently than you’ve drawn on that side, but the effect is the same. They’re not coming right back to the sensor. I would recommend using your side-sonar to help steer clear of obstacles like that.

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Chris Savage
Parallax Tech Support

wurx

Please look at my attachment first....sorry could not embed the image, strange? (Any help Chris????)

The US is giving the correct distance. The angles you have are not correct. Angle A = B, C=D etc. You should get 69 in return. The US is not particularly accurate, but it is easy to use and lots-o-fun.