MaxSonar Ultrasonic Pole/Tower Sensing & Detection Application Note!

Technical Sensors
1

MaxBotix Inc., had completed an application note that may help teams use the MaxSonar ultrasonics sensors in the 2011 FIRST competition. This note covers using the sensors for pole detection, distance, and direction to align the minibot for placement on the pole.

Please click this link to view the web page with the application note http://www.maxbotix.com/MaxBotix_Robot_Sensors.html.

In addition, we have applications notes listed on the webpage above on how to run more than one MaxSonar sensor at a time.

We wished each FIRST team the best of luck with their bot!

If you have any questions, please email me at [email protected].

Best regards,

Scott Wielenberg
Technical Support & Sales
of MaxBotix Inc.
Phone: (218) 454-0766 Ext. 2
Fax: (218) 454-0768
Email: [email protected]
Web: www.maxbotix.com

2

Anyone know how to put a DIO into the HighZ state? We’re using Java.

Thanks.

3

Configure it as an input. However, the DIO pins all have 10k pullup resistors on them. How high an impedance do you want?

4

Thanks for the question. A 10K resister will work fine. Please let me know if you have any other questions.

Best regards,

Scott Wielenberg
Technical Support & Sales
of MaxBotix Inc.
Phone: (218) 454-0766 Ext. 2
Fax: (218) 454-0768
Email: [email protected]
Web: www.maxbotix.com

5

You need to set it as a output to send the initial pulse. Then as an input to let the pulse “loop back around” from the last MaxSonar.

I was a little worried about Java not GC’ing the DigitalOutput object fast enough. But it looks like using DigitalModule.*DIO() should allow the control needed.

6

Besides the programing language time, the NI 9403 can have up to an 18 us delay in switching directions.

7

Has anyone actually gotten these working with the daisy chaining? We wired up two LV-MaxSonar-EZ4s for daisy chaining and we can get it working on a breadboard.

Unfortunately, we can’t figure out how to reconfigure a digital i/o pin as an input once it is configured as an output. We are getting an AllocateException. We are using Java. Any ideas?

8

We found the solution:

DigitalModule dm = DigitalModule.getInstance();
dm.freeDIO(pin number);
9

Will using an XL-MaxSonar-EZ0 work just as well as XL-MaxSonar-EZ0? I’ve looked at the schematic for the daisy chain and I was wondering where each of the wires get wired back to on the digital side car. Our team has limited electronic experience so any additional help would be great.

Thanks,
Team 0865

10

We use the MaxSonar modules in the analog mode. They return a value every 99 ms and work very well for us.