[SOLVED] LED lights on all the time

I have a 2.8 version and am to the point of aligning lasers. The lasers turn on and off correctly but the LEDs stay on all the time even though the cockpit indicates they should be off (using i). If I unplug the red wire from P1+ they go off but I would like to fix the control. Are the schematics available yet for the 2.8 controller board and light board? I found the 2.7 schematics but I don’t know what the differences would be. I don’t see any issues looking at the controller or BB connections. I did upgrade to 30.0.2 and have the IMU which seems to work correctly.


I’ve got the same issue with my 2.8 have you got any further with a solution for this ?



The schematics for the 2.8 Controller Board and the 2.8 Light Board were posted late last week on the GitHub site.

Are the lights on all the time or are they blinking?

Morning Brian.

Not wishing to hijack the thread but I seem to have the same issue.

New build of 2.8 straight out of the box.

The LEDs light a what I imagine is full brightness the moment that power is applied and stay solidly lit thought the boot and then solidly lit throughout irrespective of commands or what the bar graph in the browser indicates.

The LEDs don’t blink at any times and all other functionality (laser toggle, motor control / speed, camera video, camera tilt) that I can test on the bench are 100%.

Many thanks.


They are on all the time and not blinking.

Hi, i have the same problem. Everything is working but the lights are on all the time

Thanks, good to know that I’m not alone - I’m having a wade through the schematics linked above and getting a good feel for how the system works and should be able to play with the hardware later tonight.


This is concerning and we will do everything we can to get to the bottom of this issue. Unfortunately, we are not able to replicate the symptoms you are describing here in the lab yet.

@Walt_Holm are you able to shed any light on this?

Thanks Brian that is great.

To recap - 2.8 build, straight out of the box and everything works perfectly, first time - apart from the Internal illumination LEDs.

At the moment of switch on they light up at what I would imagine is full brightness and the browser control has no effect whatsoever - although the the on screen bar graph does react to the key presses.

The LED switch on is essentially instantaneous at power up - certainly no delay whilst anything boots, which makes me suspect a straight hardware issue ?

I’ll take the rov into my lab in a couple of hours - what info / pictures / scope plots would be useful to your debug efforts ?




This one is a puzzler to me. On the factory test jig for the controller boards, the functionality of the PWM outputs is fully tested- we make sure the PWM channels will turn off as well as turn on. If I could get my hands on one of the boards that is malfunctioning, it wouldn’t take long to figure out what’s going on.


You can pull the 2.8 Controller Board schematic off of our GitHub site in the electronics category. The PWM outputs are on Sheet 6. PWM1 drives the internal lights. If you have a scope or meter handy, trace the logic signal from the microcontroller I/O D44 through driver Q4. When the GUI shows that the lights are off, both sides of R36, and the gate of Q4, should be at ground.


Thanks @Walt_Holm. We will try to get our hands on one of these boards.

Is anyone that is having this problem willing to send us back their control board as well as their light board? We will replace it for you. Please PM me (@Brian_Grau) if you are able to and we can work out the shipping details… Thanks in advance.

Hi, i have thought about this issue again. Because of that the lights are on as soon i connect the power (the CPU is at this time not ready, for sure), i think could be caused by the Q4 . It seems that it is switched through all the time. I’ll check this next time in my workshop.



Evening all,

Walt - I’ve finally got a scope onto the board.

This is measured across the J1 solder pads at the Lighting Board - its a steady 9.2V irrespective of the browser settings and indication.

I disconnected the Lighting Board and connected the scope across J1 (P1+ and P1-) on the Arduino board.

This trace is full brightness indicated on the browser, but…

This trace is off as indicated on the browser, all of the steps in-between show an appropriate amount of changing PWM.

I’ll continue to investigate.


Hold on a second - I’ve just reconnected the Lighting Board but with the scope still across the J1 P1+ and P1- and the LEDs are now working correctly…

Full Brightness

LEDs off.

and finally half brightness.

Could the scope be loading Q4 ? providing a pull-down on P1- ?

I’ll continue to play but it’s midnight hers.



Ok, scope disconnected now and it’s all working 100% even after a reboot and removing the electronics module from the d type connector on the end cap.

Very odd, any ideas chaps ?



I have made some Test today and figured out that the pwm from the arduino and the q4 are working well. The Strange thing is, that the led are also on if i disconnect all the Black and red fahles which are comming from the led pcb exzept the red which is the plus for the led power. That means the LEDs are on also if they are only connected by One wire and have no ground. The only cable left which goes into this direction ist the usb cable of the Camera . I’m confused???

Finally I found the reason of this Problem … The both screws which are Gong through the LED board and the Camera board seems to connect the ground of the Camera board to the Ground of the LED Board . I have loosen this screws and the lights Switched Off and i was able to Control them via the Browser . :smiley::smiley::smiley: i have now remounted the screws and it still Works. Seems that the contact is only in a Special Position given. To avoid more of These problems i would replace the both screws against plastic ones in the kits. So far …

Good Night


I’ve got the same sneaky earth path on my Camera / Light Board and reproduce the effects reliably.

Good work - it’s good to have a solid answer rather than it just randomly working.

Nylon screws for now and don’t flood the area around the mounting holes next time you re-spin the LED pcb ?



I just replaced the screws

A huge thank you to everyone on this thread for working together to debug this problem.

We were finally able to replicate the results you were seeing in the lab.

@kruegerkreidach and @richard1 you are correct to what was going on. The PWM of the lights is done on the ground side. The metal screws that went between the light board and the camera was causing the ground planes to connect, resulting in the lights always being on.

We have made a note for the next round of light boards to increase the screw mounting area to avoid contact.

The issue with plastic screws is being able to source M2 screws that are the length we need.

We have also made a note in the directions to avoid people having the same problems in the future.

Thank you again. It is great to see the community come together to find a problem, diagnose it, and solve it.