[FTC]: NXT freeze

[Sasha]

During the NYC FTC Championship last Saturday, in two of the matches our robots NXT brick froze, so we lost control of the robot. At the end of the match, the brick would not react to any button presses; we had to remove the battery to bring it back to life. Some of the other teams had the same problems, too - and it never happened to us before in the home practice, in qualifiers or other championship.

The field technical adviser suggested that the cause may be static buildup: a static discharge can cause voltage jump in the wiring leading to NXT. He suggested adding a grounding wire to the robot.

Anyone else experienced similar problems? Any suggestions?

[pyroslev]

There are some competitions where I don't see a single lockup and then there are some where we see to many.

As far as the ground wire goes, no. For FRC robots it works but FTC robots not as much. It's actually posted in the forum as something that is not legal.
http://ftcforum.usfirst.org/showthre...ull=1#post7994

There have been multiple threads on the topic but here is the latest one.
http://www.chiefdelphi.com/forums/sh...hreadid=127587

[ehochstein]

I am the Lead FTA for Minnesota, I find the best way to solve this problem in cold, dry climates is to spray the field with water every other match. At the Minnesota State Competition we had at maximum 2 or 3 times that a robot froze on the field.

The tiles are insulators, putting a "grounding wire" on your robot will not do much.

[Sasha]

Originally Posted by pyroslev

There are some competitions where I don't see a single lockup and then there are some where we see to many.

As far as the ground wire goes, no. For FRC robots it works but FTC robots not as much. It's actually posted in the forum as something that is not legal.
http://ftcforum.usfirst.org/showthre...ull=1#post7994

There have been multiple threads on the topic but here is the latest one.
http://www.chiefdelphi.com/forums/sh...hreadid=127587

Thanks! we will investigate.
However, in our case the motor controllers are mounted on plywood, which in turn is attached to Lexan sheets forming the sides of the robot - no direct connection to the frame. I should check the wiring... maybe hide all wiring inside a sleeve.

Sasha

[pyroslev]

Originally Posted by Sasha

I should check the wiring... maybe hide all wiring inside a sleeve.

Loose and exposed wires are fertile ground. It allows discharges into your electronics. It also potentially charges the frame. It can become a 2-way street for the charge to balance depending on your circumstances.