Ultrasonic Sensors

[nathanww]

I'm not a labview programmer, but as I understand the built-in ultrasonics routines are for digital ultrasonic sensors(the system sends out a ping and then waits to hear the returning ping). The maxbotics has a coprocessor that does this, so instead of using digital pulses, it just sends you back an analog value, which you can read the same way you'd read a potentiometer.

[Tom Line]

Originally Posted by nathanww

I'm not a labview programmer, but as I understand the built-in ultrasonics routines are for digital ultrasonic sensors(the system sends out a ping and then waits to hear the returning ping). The maxbotics has a coprocessor that does this, so instead of using digital pulses, it just sends you back an analog value, which you can read the same way you'd read a potentiometer.

The maxbotics will send PWM values or analog values. Take your pick.

If you use the analog values, you can simply read the analog channel and divide by a constant to get number of inches.

No idea about the ultrasonics sensor VI - it was easier for me to do it the way I stated since we used them last year.

[windell747]

I'm not sure how to get the sensors working with the labview tutorial, but if you have the ones that output an analog voltage I can imagine you can just read in the value as an analog input and scale that value by a constant by multiplying a constant to it.

[tennisbeast29]

I was thinking about using an ultrasonic range finder. It's very good at detecting walls and other solid objects.

But for robots, which have different sized parts hanging about and holes everywhere that could have echos, I thought it wouldn't really be accurate because they would all affect the distance. This is my first year so I'm not sure, did this system work for anyone?

[MrForbes]

Originally Posted by mikeqfl

Has anyone tried using the camera for ranging information? Is there a canned routine in Labview to do that? Any feedback on how accurate it is? We are using a camera to track the the opposing trailer and need range feedback to feed to our shooting mechanism. We almost have all of the mechanical stuff worked out, time to program and try to make it all work now. Nothing like saving the best for last.

We have set up a routine for doing this, it works ok, but we need to do some more work on our shooter system to get consistent shooting speeds (speed sensor so we can command a specific shooter RPM for the detected distance, rather than just sending a PWM value to the shooter speed controller).

http://www.youtube.com/watch?v=eTCr2nvFn3g

We played with an ultrasonic sensor a bit to see if it would work...didn't really see any advantage to it. Although we did not try aiming it up at the vision target, which might work better. The problem is the beam width requires the shooter to be aimed right at the target before it can get a good range number, whereas the camera routine only needs the target to be in the field of vision, which is much wider.