Ultrasonic Sesnor Accuracy

[SoyStuff]

Thanks for your help, everybody. We've got it working properly now. We were measuring distance to a wooden board, but the board was not quite perpendicular to the sensor, and it was warped. Today, we got a bigger, straighter board, used a measuring tape instead of a bunch of meter sticks, and took readings at intervals of 50cm. Now, we have an equation that works. Again, we appreciate your help. We didn't realize that the angle of the board would have such a tremendous effect. To compensate for that, we've coded some gyro stuff, and everything seems to be going smoothly so far.

[Chris Hibner]

Originally Posted by SoyStuff

Thanks for your help, everybody. We've got it working properly now. We were measuring distance to a wooden board, but the board was not quite perpendicular to the sensor, and it was warped. Today, we got a bigger, straighter board, used a measuring tape instead of a bunch of meter sticks, and took readings at intervals of 50cm. Now, we have an equation that works. Again, we appreciate your help. We didn't realize that the angle of the board would have such a tremendous effect. To compensate for that, we've coded some gyro stuff, and everything seems to be going smoothly so far.

Excellent. Good to hear. What accuracy to you have now?

[ayeckley]

Just to add another data point, when we first tested the sensor we found huge intermittent drops in the measured range when more than 8' from the target wall, even with a properly-initialized sensor, perpendicular target, clear range to target etc. Two days later the problem did not recur even with no changes to the hardware or software. The leading theory so far (which we will test at the next opportunity) is that all of the grinding noise from the welding class going on next door had a high ultrasonic spectral content which interfered with the unit. Without the grinding noise two days later, the sensor was well-behaved.

[Dale]

Hmmm...grinding noises could sound a lot like robot noises whether our own robots or other robots on the field! This is certainly something to test.

[Gdeaver]

Like the sound of chain running at 5000 RPM?