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Old Jul 19, 2011, 03:42 AM
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Denmark, Capital Region of Denmark, Naerum
Joined Feb 2011
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Quote:
Originally Posted by carlonb View Post
Hi dennis,
please continue, I like this idea to built my own OSD as i like fly , programming and electronics.
Please submit a schematic.
Ciao, Carlo
I would like to make a few more hardware-tests and make a flexible solution (with standard components and a little trim-pot), before I upload the schematic.
In generel, the only thing that has to be done is to adjust the video-signal, with the same circuit as shown on wikipedia (the bias voltage goes to the "+" just above the capacitor);
http://en.wikipedia.org/wiki/File:Po...ng_Circuit.svg
A finish circuit can be seen here (not mine);
http://www.viennawireless.org/balloo...rlay/index.php
http://www.circuitcellar.com/avr2004/DA3754.html

This guy is only using a resistor. I wouldn't thrust the sync detection, but you might be lucky. And when using SPI, i recommend also to use a diode from the SPI-pin
http://diydrones.com/profiles/blogs/...as-osd-without

But I find that a standard diode provide too low voltage for the bias-circuit, to raise the video-signal above ground.

I'm currently using a zener-diode to create the voltage reference and bias voltage - but I would prefer to use standard components all the way. That would make things easier available for everyone
2 Diodes en series could be a solution - but that's a boring solution (though it works fine)
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Last edited by Dennis Frie; Jul 19, 2011 at 03:52 AM.
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