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cupidmoon / arducam-osd

Automatically exported from code.google.com/p/arducam-osd
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Horizontal noise in overlay. #14

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
Please see the horizontal noise in this video:
http://youtu.be/F-t7Y4tqq5k

-5V is provided by a switchmode BEC (usually very clean power)
-no servos moving

No difference no matter what I tried:
-both parts of MinimOSD running on 5V (no camera)
-adding 10UF, 1uF or 10nF capacitor across GND/VCC on the MiniOSD
-using a separate 12V source (another battery)  - with only GND in common

Where is this noise coming from ?
judging by how often the noise appears, may it be the Atmel working  - 
receiving MAVLink ?

Original issue reported on code.google.com by andre.kj...@gmail.com on 13 Feb 2012 at 1:42

GoogleCodeExporter commented 9 years ago 
Please, we need some more information.
What happens when you add a camera signal? (It could be about MAX7456's 
internal sync).
The BEC is feeding APM which feeds OSD, right?
Notice that even stopped servos could be pulsing a bit.

Though some of those little glitches are usual in analog video, to achieve the 
most clean signal as possible you should use the original two stages of 
MinimOSD (instructions on wiki). Just keep in mind that it works considerably 
hot (needs to be attached to an air cooled place).

Original comment by sbeni...@gmail.com on 14 Feb 2012 at 10:54

GoogleCodeExporter commented 9 years ago 
This is not a defect. To solve it, just use a dedicated battery to feed the 
second power stage of MinimOSD.

Original comment by sbeni...@gmail.com on 10 Apr 2012 at 6:37

GoogleCodeExporter commented 9 years ago 
I tried: (as described in first report)
"-using a separate 12V source (another battery)  - with only GND in common"

Anyway, it's not a big issue, just wanted you to know - so the design can be 
improved.

Original comment by andre.kj...@gmail.com on 10 Apr 2012 at 8:54