Ultra Sonic range finder Possible Problems

[rhf323]

Hey Guys
I may have found a problem when multiply teams use the ultra sonic range range finder. In my past experiences when using a few of these sensors at the same time they interfere each other causing their data to be Highly inaccuracy. The reason for this is that they way sensors work is that the send out a sound inaudible to the human ear and time how long it takes for it to return to the source. Then through some simple math the distance is found. But when 2 sensors are used sensor #1 can pick up the initial sound from sensor #2 causing sensor #1 to out put incorrect data.
So any thoughts on sloving this problem if it does exist?

[theprgramerdude]

The MaxBotix sensors found the in the kit of parts have a pinout that is detailed here: http://maxbotix.com/products/MB1010.htm

As can be found on the data sheet, there's not only reading outputs, but pin 4, the RX pin, is internally pulled high. By pulling this low (connecting to ground), the sensor will automatically stop ranging.

If you can control when the pin is pulled low, you can control which sensors are ranging at any moment, and thus alternate readings between sensors to prevent any interference.

Edit: In order to do this, You can create a digital output pin on the sidecar, hook it up to the pin on that sensor, and set it to low (pulling the pin low as a result).

[Kovs]

If you can control when the pin is pulled low, you can control which sensors are ranging at any moment, and thus alternate readings between sensors to prevent any interference.

Good to know when dealing with two on the same bot, but I think rhf323 was more concerned about ultrasonic interference with multiple bots equipped with ultrasonic. I am interested too.

[theprgramerdude]

Good to know when dealing with two on the same bot, but I think rhf323 was more concerned about ultrasonic interference with multiple bots equipped with ultrasonic. I am interested too.

Hopefully, I can get in touch with the MaxBotix founder tomorrow and get a more precise answer; for now, when we talked last year about a different class (XL-AE, a more advanced model) of sensor, the range readings are generally resistant because they're constantly calibrated to avoid interference.

Since the LV model doesn't do this, I believe it might be more susceptible to interfere, but as I said, I don't have good experience with this class.

If you upgrade to the AE model, I know it's actually very easy to determine whether any interference could be occurring by getting continuous readings from the AE output.

[ScottW of MaxBo]

Salutations, This is Tom Bonar from MaxBotix Inc. We currently are having an ongoing thread on our Facebook page with the Tech Support questions and answers from the teams. If you look at http://www.facebook.com/note.php?note_id=277662868954588 numbers 1 and 2 you should find the answers your inquiring about.

Good luck with the competition.