navX Issues

[slibert]

Originally Posted by s5511

During yesterday at tournament, our navX gyro sensor stopped returning values, causing our drivetrain PID to malfunction. The navX is protected by a plastic casing and is still directly plugged into the roborio. Are there any reasons that could cause the navX to stop functioning like this? We have been using it for over 4 weeks, and it has been working fine.

This is repeating the fine advice given by others, but the most likely issue is that the 5V power source to the navX-MXP, provided by the RoboRIO via the MXP connector, was cut due to a Stage 2 brownout. A related failure condition is the 5V power source was cut due to a short circuit that the RoboRIO detected as a current surge.

In each of these cases, the navX-MXP would lose power, and then begin re-initializing once power was restored. In the case of a stage 2 brownout, power could be restored as quickly as 100ms later, it just depends upon the conditions.

As discussed in the "Best Practices guide", using a USB cable to provide backup power in case the RoboRIO cuts the MXP power will address this issue.

Here at Kauai Labs, we have this year seen a few times a more fatal issue. Due to excessive current draw on the expansion IO pins, one of the expansion IO power (3.3V/5V depending upon the jumper setting on the navX-MXP) traces, or the ground return trace, can become damaged. This may cause the MXP power source to the navX-MXP processor to no longer work (a USB cable would fix this), and also mean that the power to anything connected to the Expansion IO pins on the navX-MXP would not work. If you see visible evidence of a burnt trace on the navX-MXP, please let us know (support@kauailabs.com) and we'll work with you to replace your board.

Aloha,

- scott