[FTC]: NXT Lockups in LabVIEW

[PhilBot]

Hi

Over the last two days, I've had my NXT lock up twice during Teleop.

Fresh Batteries, New NXT, Correct Firmware, Correct template.

I have used some advanced Labview coding, but nothing that has been reported as not supported.

The weird thing is that when it happens, the NXT goes into that tick tick tick mode that occurs during a firmware update. The screen just freezes and you need to pull the batteries. Works fine on replacing the batteries.

Before I head down the long road of trying to get this to occur on demand, anyone seen anything similar with a well defined cause? No conjecture or speculation please.....

Phil.

[ferret_guy]

when I did (and mentored) ftc and fll this happened alot it is a sign of the brick dying and has nothing to do with the code you might be able to send it back for repair/replacment

[TRWSHSHLX]

Last year when our robot's NXT locked up, we found out it was due to static electricity build up. Was the robot mechanically altered in anyway right before the lock ups start occurring? Also, is your robot grounded?

[VashonRobotics]

Curious how you came to the conclusion that it was static build-up? What was causing it? What was being affected? (NXT, Samantha, etc) How did you end up solving it? Thanks!

[TRWSHSHLX]

We put anti-slip mat or some sort of "absorbing" material around the NXT to lessen the vibrations that occurs during match play. And after that change, the NXT would lock up just randomly. It was also partially due to the high traction tires we have on the robot.

Nothing else seemed to be affected. We found a better way of shock proving the NXT and added a grounding wire and NXT didn't freeze up anymore.

[BornaE]

Originally Posted by PhilBot

Hi

Over the last two days, I've had my NXT lock up twice during Teleop.

Fresh Batteries, New NXT, Correct Firmware, Correct template.

I have used some advanced Labview coding, but nothing that has been reported as not supported.

The weird thing is that when it happens, the NXT goes into that tick tick tick mode that occurs during a firmware update. The screen just freezes and you need to pull the batteries. Works fine on replacing the batteries.

Before I head down the long road of trying to get this to occur on demand, anyone seen anything similar with a well defined cause? No conjecture or speculation please.....

Phil.

Phil,
Any updates on this? While helping 4314 I encountered the same issue, However this happens very consistently using tether or samantha. I do hear the clicking noise a couple of seconds after enabling the robot.

The code is very basic. The only addition beside regular VI's is the hitechnic prototype board VI to read an analog.

Spent about 2 hours troubleshooting this with no luck.

While I have done some more advanced stuff in labview and I am a fan, The FTC implementation of labview in addition to the NXT has just been bad. And especially horrible this season. Just my opinion.

[PhilBot]

Originally Posted by BornaE

Phil,
Any updates on this? While helping 4314 I encountered the same issue, However this happens very consistently using tether or samantha. I do hear the clicking noise a couple of seconds after enabling the robot.

The code is very basic. The only addition beside regular VI's is the hitechnic prototype board VI to read an analog.

Spent about 2 hours troubleshooting this with no luck.

Hi

After we had this happen a few times, one of the kids thought he remembered that it had hapenned on their robot a few years back and it was "caused" but metal shavings falling into the NXT wire sockets on the motor/servo controllers.... that is... an electrical problem on the communications bus.

While I didn't specifically recall this (or believe it) , I thought it was probably a good idea to ensure that all the connectors were free of debris, so we did a serious vacuum inside all the sockets, and then we put electrical tape over all the open connectors sockets.

Oddly enough, we haven't seen the lockup since them (knock wood).

The fact that you are using the prototype board might indicate that you possibly have a bad connection that is also effecting the communications on the NXT data bus.

Do you get the same problem if you unplug the proto board?

Phil.

[iPenguin]

Originally Posted by TRWSHSHLX

Last year when our robot's NXT locked up, we found out it was due to static electricity build up.

Originally Posted by PhilBot

After we had this happen a few times, one of the kids thought he remembered that it had hapenned on their robot a few years back and it was "caused" but metal shavings falling into the NXT wire sockets on the motor/servo controllers.... that is... an electrical problem on the communications bus.

As an FTA, I can confirm that both of these cases can be likely causes of the NXT locking up. I don't believe it has anything to do with specifically using LabVIEW or RobotC - I've seen equal cases of both. What can happen is that Samantha will for some reason send a "bad message" to the NXT, and the NXT doesn't know what to do with it, and therefore locks up. I've spoken with other FTA's and, unfortunately, we really don't know why this happens, or what to do to prevent it.

Phil's suggestions for vacuuming and covering unused ports are good ideas. That USB cable between NXT and Samantha is very critical. Make sure it is secured tightly. It's also been suggested to get a couple small USB extension cords that permanently stay attached to the NXT and Samantha. This also helps for your Software Inspectors who need easy access to Samantha's USB port.

Hope this helps!

[pyroslev]

Originally Posted by iPenguin

Hope this helps!

It does help and I second your conclusions. I've noticed the lockups don't have a code preference. But when some of those hits between robots occur, you get robot lockups later in the match.

As a request from an FTA, if a lockup occurs, it helps to diagnose the robot if the NXT is visible and to turn it off if the power switch is easily reachable. It hurts when I have let a robot death spiral cause the power switch is under the robot lifter or NXT.

[Hodgepodgerama]

All, there is now an excellent article on the FTC Team Resources page on NXT lock ups. It covers the issue and how to resolve it. We purchased the item mentioned in the article and have had no lock ups.