Bridge resetting

On our prototype bot, we have the strangest bug. The robot runs fine when tethered, and it stays connected through the router as long as I don’t turn on the motors. But as soon as I run the motors, we loose robot connection and then it comes back a half second later. Has anyone ever had a resetting router? Any ideas how to fix it? I’d be happy to provide any other information you think might be useful.


  • When we built this we didn’t have the power converter, so our bridge is connected directly to the 5V plug meant for the camera. Could that be it?

  • I made a video of the problem: (you can see the drivers station and hear the motors).

  • I tested the plug that goes into the bridge with a multimeter (when it’s out of the bridge), and even when I’m jamming the motors it doesn’t vary from 5.08V

  • The power light on the bridge turns off when the connection drops

  • There are no chain runs on the robot, so the gearboxes are not taking any load

  • Battery voltage reads 12.5V on a multimeter, I charged it very recently.


  • Alex

ever since we took home our last years robot it seems to do something kind of similar. Ours is a programming issue, if you have the same problem as us then the console should read “watch dog not fed” in which case i would direct your queries in search of how to fix the “watch dog” but im not sure if thats the problem

2 Things it might be…

One: Ensure that all the connections are secure. (Power, ethernet (to bridge and cRIO)

Two: This is more likely… How are you powering the bridge? Make sure you ae using the dedicated 12V power supply (there is only ONE!) and going through the supplied power convertor. Do NOT use one of the 20 12V power blocks, those are for your motors.

In addition- make sure your cRIO is connected with the 24V connector also…

And if you connect directly tethered to the cRIO (NOT using the bridge), does the same problem occur?

This is just a guess, but check to make sure you wired the router to the power distribution board properly. We had a similar issue last year.

It shouldn’t be connected to the main black/red outputs, it should be connected to the voltage converter located in the KOP, and the converter should then be connected to a WAGO connector which fits in the beige-colored 12v output at the bottom of the board.

If it’s connected to the black/red outputs, the motors might be drawing too much power away from the router and causing it to briefly shut off.

Take a look at this example diagram:

And info about the PDB:

And be sure the battery is charged, of course.

Probably. I don’t think that supply should die quite that easily with a good battery but you don’t have the battery monitoring jumper in place so it you can’t see what your battery voltage is at. The 5V supply definitely doesn’t have the protections against battery voltage sag that the 12V “robot radio” connector has.

The current bridge is 5V. Don’t directly wire it to the 12V!!! use the power convertor.

Rule 42 B is specific on how the Bridge is suppose to be wired. Wiring it differently could cause the issue you described. Power light blinking is a good indication of some kind of power or wiring problem. Are you using the right plug for the bridge? If not, you could have one that mostly works.

Also the bridge should not be next to motor & have a good line of site

Wish I could see the robot.

If there are 2 motors on each gearbox, are you sure they are wired to turn in the same direction, and not fight each other?

Two things I can think of:

  • Make sure the wireless bridge gets the 5V from the DC-DC converter that converts 12V to 5V and not directly from the 5V that was meant to be for the camera. Since you said you did use the 5V meant to be for the camera, that’s probably the reason. When the motor runs, it may cause this 5V output to drop which will cause the D-Link to reboot.
  • Did you buy and make your own D-Link power connector or did you cut the power connector from the original D-Link power adapter and reuse that? There is a possibility if you buy your connector that it did not have the correct inner diameter so you may not have a good power connection to the D-Link. Then you will have intermittent power loss of the D-Link causing it to reboot.

The +5 power supply for the camera cannot supply both the DAP and the camera. The 5 volt convertor in the KOP is required to be wired to the +12 output on the PD. All power supplies on the PD are designed to continue supplying the stated voltage until the battery voltage falls to 4.5 volt for a significant length of time. (close to a second) At 4.5 volts the power supplies stop producing voltage. If that were the case, the Crio would also reboot. This is a classic description of the 5 volt convertor being wired to a breaker output on the side of the PD, not the dedicated +12 volt output at the end of the PD.