Oct 24, 2006

Compass Sensor use in FLL


A new question was just added to the Q&A section of FLL today about Compass Sensor use. The answer is a definite "no" for 2006/2007, but use in future competitions is undecided as of yet.

13 comments:

Jim Kelly said...

Question #11 is also interesting - if I understand it correctly, it's saying that the Ultrasonic sensor CAN be used - it says the RULES are the final word, not the Coach's Handbook (which supposedly said it was not allowed in play).

Should be interesting seeing how that works...

Jim

Jim Kelly said...

I guess this means my Bacon Sensor will also not be allowed.

Jim

eric said...

Dude, I totally want a Bacon Sensor!

Jim Kelly said...

Eric,

When they start to roll off the production line, I'll send you a free one :)

David Levy said...

More on the Ultrasonic sensor:
There are warnings in the FLL forum that the its use may be problematic given that u-sensors on other robots may be in use. The forum stresses that they should be placed as low to the table as possible and to be activated for only short periods of time.

Jonathan said...

Yeah, I think a US sensor would be more of a problem rather than a help. My team isn't using any sensors this year except the built-in rotation sensors, and it's going quite well - all the missions are working perfectly. :)

-Jonathan

Maniac... said...

Dead reckoning?

*chokes*

My coach would kill us if we relied solely on the rotation sensors.

Jim Kelly said...

FLL teams should use all the tools at their disposal, including the Ultrasonic sensor... with some tweaking, it can be turned into a sensitive touch sensor...

Jim

Jonathan said...

Maniac,

Lol, that's what we're doing.

I don't think your coach would kill you if he/she saw how our missions ran. ;-)

-Jonathan

Brian Davis said...

David Levy wrote: "...to be activated for only short periods of time." Interesting, as I know of no way from NXT-G to toggle the sensor on or off. In fact, a plugged in US sensor is on from the moment power is up on the NXT (even if a program isn't running). "turning it off" from a NXT-G program is not, to my knowledge, currently possible. Is it under Robolab 2.9?

As to "relied only on roation sensors", I would use what I can, especially the rotation sensors. You can use them for so many things beyond "dead reckoning", for instance. and even dead reckoning is no longer quite so "deadly" as it was with the RCX. The US sensor as a touch sensor is an excellent one, Jim - also, you can filter out "false" signals under a lot fo conditions (for instance, stop your robot - if the US return keeps changing distance, ignore it and wait for a "good" reading that is stable).

--
Brian Davis

David Levy said...

Brian,
Maybe I confused you when I used the term "activated"

I don't remember the original quote but I suppose they were referring to the following:

pgm1
1- move forward forever
2- u-sensor wait until < 10

pgm2
1 - move forward 6 rotations
2 - move forward forever
3 - u-sensor wait until < 10


pgm2 uses the u-sensor for a shorter period thus limiting exposure to other robot interference

Anonymous said...

Brian's point is that if an ultrasonic sensor is plugged into a sensor port on an NXT it immediately begins pinging, whether your running program actually uses it or not. In NXT-G there is no way to stop it from pinging.

Every NXT bot with a US sensor plugged in will be causing interference as long as the NXT is turned on.

John Hansen

David Levy said...

Yes. You'll be CAUSING interference the moment you power up.

Still, would pgm2 reduce the chance of being adversely affected by interference caused by other robots?

I suppose this is a moot question. Why take a chance?

-dl

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