Minimosd - nothing on screen

Archive
1

I have apm and minimosd connected.
i can see onscreen info from my copter.
if i connect the usb i read on the display "NO MAVLINK DATA"
i think it is correct since when i unplug the usb, the mavlink data start to arrive and writes are reported on the display.

This is the problem: sometimes, after takeoff the labels (the onscreen info) disappear from the display (i continue to see only the video from the camera).
In this situation i can continue to fly, but i can’t never see again the onscreen info until i reset the APM and minimosd (i unplugged the battery).

I also tried to reset the minimosd without success.

This is the question: What is the difference between the message “NO MAVLINK DATA” and the absence of onscreen info?

i hope that your answer could help me in the troubleshooting.
actually i don’t know if the problem is the apm or the minimosd.

thank you.

2

No mav link data means the apm is not sending any data to the minimosd. No text at all is the minimosd having an issue, possibly browning out.

3

thank you.
so i must concentrate on minimosd.
i supply it with the same +5V that supplies the APM (it comes from a BEC)
Could it be possible that too much vibrations causes these problems on minimosd?
What could i check?

4

Vibrations are unlikely I’d have thought.
My minimosd used to blink off every flight, sometimes after a few seconds other times it would take a few minutes.
I used to have the 5v from the apm telemetry wiring powering the osd (as per the instructions) but after I started powering the osd with its own 5v ubec I’ve not had a single problem with it. That’s also with the 2 solder joints made so it doesnt need 12v on the video side of the osd.

5

[quote=“MarkM”]Vibrations are unlikely I’d have thought.
My minimosd used to blink off every flight, sometimes after a few seconds other times it would take a few minutes.
I used to have the 5v from the apm telemetry wiring powering the osd (as per the instructions) but after I started powering the osd with its own 5v ubec I’ve not had a single problem with it. That’s also with the 2 solder joints made so it doesnt need 12v on the video side of the osd.[/quote]

Forgive me, i’m not sure if i well understood:

You had my same problem in my same configuration (power from APM).
Finally you solved the problem by powering the minimosd with a dedicate BEC (from another ESC).
did i correctly understood?

6

Almost, I use a totally separate ubec just for the minimosd not one of the esc bec’s.

7

i suppose that BECs from the ESC are stable enough since they can be used to supply the APM.
Am i Wrong?
I did this modification. I’ll fly as soon as possible and I’ll post here the results.

the strange thing is that i had this problem few times at the beginning of my tests, then i haven’t any problem for at least 10 flights. now the problem is returned again. Isn’t it strange?