ROV went over dam now navigator board wont comunicate

General Discussion
1

Hi,

I was doing a dam inspection, and the rov went over a small dam. There was a little damage to the frame, but didn’t look like anything major.

I after recovering the ROV, we went for a second attempt the ROV booted up and worked for a little until it said the ROV lost communications but the video stream was still coming in.

I rebooted the ROV, and the video came through, but there was no communication. I opened Blue OS in the web browser and noticed the navigator was not communicating the Raspberry Pie.

I’m at my shop now trying to troubleshoot the issue. I replaced the raspberry pie and navigator with a new one, but I still have the same issue. OTPS. Powers the ROV and is in a heavy configuration. I checked all the voltages, the 5 v, and I got 5.13 v on both 5 v connectors, and I got 15.9 v coming in from the power supply.

I don’t know what would be causing the navigator to not communicate with the raspberry pie. My only idea is that maybe one of the thrusters or other peripherals shorted out and damaged the navigator. As I reconnected everything when I installed the new navigator and raspberry pie.

My questions are: what could be causing the navigator to not communicate with the raspberry pie, and how would I check the thruster to see if they have a short that would damage the electronics? any Ideas would be helpfull

2

Hi @CUIS -
That’s very strange! It isn’t possible for the ESCs/Thrusters to damage the Navigator.
Are you running the latest stable BlueOS, 1.3.1?
I would recommend looking at the Autopilot Firmware page, and seeing if you’re able to flash 4.1.2 to the autopilot. If no board is detected, then something may be wrong with the Raspberry PI? Verify that the Navigator is correctly plugged into the Pi GPIO pins, and please share pictures of the lights it may be producing.

3

Yes, I am running the latest Blue OS.

and I connot check the autopilot firmware as it is not communicating with the raspberi pie. it is not being detected. on both the old and new navigator and pie.

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dead Navigator
dead Navigator1920×1128 240 KB

4

@CUIS since you’ve already swapped both raspberry and navigator with two new units and you’re still getting the same issue, did you try also to re-flash the raspberry SD card with a new fresh Blueos installation?

As @tony-white said, it is really strange that a faulty esc / thrusters can damage the navigator at the stage that cannot be recognized anymore by Blueos.

5

Hi, Yes, I tried reflashing the SD card and swapping both the pies and the navigators.

I looked under a magnifying glass, and it appears the navigator have some chips that are fried.

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IMG_20240910_131716-1
IMG_20240910_131716-11059×1412 98.8 KB

I tested the voltages from the connected devices and I get the following:

For voltages, I get the following.

From the negative terminal, the main power source

0.9 volts coming off of the signal wire for the lights, 6.3 volts coming off of the delta ROV laser scaler signal wire, and 2.4 volts coming off of the Newton gripper signal wire

From the positive terminal, the main power source

15.7 volts coming off of the signal wire for the lights, 9.6 volts coming off of the delta ROV laser scaler signal wire, and 1.5 volts coming off of the Newton gripper signal wire

From the negative terminal, 5v power

0.09 volts coming off of the signal wire for the lights, 6.3 volts coming off of the delta ROV laser scaler signal wire, and 2.4 volts coming off of the Newton gripper signal wire

From the positive terminal, 5v power

5 volts coming off of the signal wire for the lights, 1.2 volts coming off of the delta ROV laser scaler signal wire, and 2.7 volts coming off of the Newton gripper signal wire

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6

@CUIS definitely the Navigato has some problem. The ADC ic seems blow up .
Consider the voltage measurement should be always referred to the Negative BUS as you shouldn’t have any isolated DCDC.

Saying this, can u confirm the 6,3v you’ve got on the lasers are with the negative probe on the Negative BUS and the positive probe on the laser signal wire?
If so you definitely have some issue with the lasers.
Consider the Navigator I/O pins voltages range is 3.3v.

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7

Yes that is correct

8

Hi @CUIS -
@SubseaLED is correct - it would seem your laser scaler is the most likely culprit responsible for damaging your Navigator. I would recommend not connecting it to any hardware until it is repaired to not output voltage on the signal pin…

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