PIXHAWK and micro MinimOSD voltage problem

Hardware Pixhawk family
1

Hello friends,

I have a pixhawk 2 on a traditional heli. All is fine for flying.
I would like to add a video system. So, I want to power video circuit with second 3S battery. No a problem.
BUT
I put a microminimosd and this is my problem. A ground problem in fact…
because video circuit (cam and vtx) is 12V power. OSD is 5V power. and pixhawk TX/RX signals 3.3V
with 2 separates batteries, OSD is the place where all voltages are encounter…
Pixhawk telem1 (serial1) seem to be unable to power the microminimosd with the telemetry 3DR too.

somebody could send me a draw of theorique wiring for this mount? with 2 batt?

thanks

2

I am assuming this is the OSD that your using.

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If so there is no where on the OSD to connect the 12vdc. However this OSD cannot be powered from the Pixhawk, it sucks to much juice and is prone to brown out. Power it direct from a 5vdc bec if you can.

3

Yes. This one.
No 12v at all on it. But the video signals (in and out) are not 12v. It’s 5v.
12v cam and vtx is directly wired on themselves.

I’ve tried to put 5v from bec connect to video 11.1v batt. But the voltage mixing is mad.
The pixhawk was powered from video batt…
So, I think it’s impossible to use this osd with second batt. Need a minimosd wich have 2 stage voltage input.

4

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5

yeah…
I’ll try this.
thank you

6

OK,
I tried. It’s OK, you are right.
video circuit is independante now.

Second problem… no data send to OSD…
it was the same before your connect diagram.
Seems to have a protocol problem.

7

I’ve got an OSD on Telem1, but you can easily change these settings if you’re using Telem2 (serial2)

TELEM_DELAY,2
DEV_OPTIONS,2
SERIAL1_PROTOCOL,1
SERIAL1_BAUD,57
SERIAL1_OPTIONS,0
SR1_RAW_SENS,2
SR1_EXT_STAT,3
SR1_RC_CHAN,2
SR1_RAW_CTRL,2
SR1_POSITION,4
SR1_EXTRA1,10
SR1_EXTRA2,5
SR1_EXTRA3,3
SR1_PARAMS,0
SR1_ADSB,0

8

Also make sure yo have the TX going to the OSD rx and the RX going to the OSD Tx.