Trying to turn lasers on causes battery to drop to 0V then camera will not work


I have completed building the OpenROV 2.8 and have succesfully gotten the Cockpit, camera, and motors to work. The issues begin when I try to turn on the lasers. When I type “L,” it causes the battery voltage to briefly drop to 0 volts which causes the ROV to reboot. After rebooting, the voltage goes back to normal, but the camera image on the Cockpit goes black and will not resume until I reboot the ROV again. In addition to this, unplugging the USB cable does not power down the ROV. I have to pull the batteries out. I am in a bit of a time crunch to get this ROV finished, so I can use it for my thesis. Any help is greatly appreciated.

I have already tried updating the Beagle Backbone with 30.0.3. I also updated the firmware. All three lights on the homeplug connect either light up or blink.


The symptoms you describe for the lasers are generally caused by either a short-circuit in the soldering on the light board, or a mixup in inserting the four wires from the laser board into the headers on the Control Board.

I would start by checking over all the wiring and looking closely at the solder joints on the light board to make sure that there are no shorts. If you don’t find any issues, disconnect the four light board wires from the controller board, and start testing while you incrementally plug stuff back in. With no wires connected, does pressing L cause the ROV to reboot? Then just install the two wires for the lights. Do the lights work correctly? does pressing L cause the ROV to reboot? Then finally reinstall the two wires for the lasers. Do the lasers now work correctly, or do they cause the ROV to reboot?

By breaking down the problem like this, you should be able to find the cause pretty quickly.

Once you have dealt with the lasers issue, we can move on to the power switch issue. That one will probably require the use of a voltmeter to diagnose.



After @Walt_Holm’s comprehensive answer I can only add, that I had issues with light board caused by the screws. If you tighten them to much they sometimes cause small shortages. So you may also check that the screws are not too tight.


Thanks so much!!! The solder joints on the light board were causing shorts.


@Fe3C Good point about the light board screws, although it doesn’t sound like that’s the issue here.

The original light boards for 2.8 had an issue where if you tightened the camera screws too tight, it would cause a short in the wiring and could lead to power shorting issues. This was fixed around December of 2015 with the “A” revision of the light board (It says 2.8A on the back), which cut back the copper pour around the screw holes. If you have an original version of the 2.8 light board, you need to be careful about either not overtightening the camera screws, or add a nylon washer or other insulating material underneath the head of the screw. I think there’s something about this in the Dozuki instructions, but I’m not sure.

@katieclevenger02 let us know if you still have issues with the ROV being on all the time.



It still stays on after I pull the USB cable. If you can give me some pointers on how to fix that problem, that would be great. I am going to start testing it in a pool, but definitely want to get that fixed before I put it in open water.

@Fe3C Thanks for the tip. I went ahead and backed off the screws a little bit just in case.