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Old Aug 02, 2011, 04:52 PM
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Originally Posted by Dennis Frie View Post
Video in and out is the same
You don't have to connect it "between" your camera and video-tx. You can just split the video-signal and connect a separate wire to the OSD.
I don't understand this, so if the signal is split before it arrives into the arduino there wouldn't be any overlay transmitted, so it's split as it goes out of the video out,...could you maybe draw a sketch to clarify?

Also there is a lot of schematics around in the thread, which one do you use (and which is best)? What is the purpuse of other schematics - in simple terms?

I plan to use that dealextreme nano, and the same gps you use so probably no problems in that area, current sensor probably also the same since I won't know how to modify the code if I use the flytron 50A sensor..

Everyone has it's own expertise, I'm a student of pharmacy so I'm good with molecules but bad with circuits
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Old Aug 02, 2011, 05:02 PM
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Originally Posted by SouthPawPaul View Post
Thanks for the reply, but it's all over for me for a while. I just reverse connected the video out to the video in on my 2.4ghz Tx and some magic smoke fizzed out of the back of my DX-201.

Really bummed right now. You'd have thought these things have reverse polarity protection built in.
Auch, sorry to hear that. You can't identify the "smoked component" and replace it?
Was it only the video-out you connected wrong? My cheap HK camera output have been connected directly to ground, VCC and randomly pulsed with SPI output, constant high SPI output etc. without taking damage.
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Old Aug 02, 2011, 05:15 PM
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Quote:
Originally Posted by msev View Post
I don't understand this, so if the signal is split before it arrives into the arduino there wouldn't be any overlay transmitted, so it's split as it goes out of the video out,...could you maybe draw a sketch to clarify?

Also there is a lot of schematics around in the thread, which one do you use (and which is best)? What is the purpuse of other schematics - in simple terms?

I plan to use that dealextreme nano, and the same gps you use so probably no problems in that area, current sensor probably also the same since I won't know how to modify the code if I use the flytron 50A sensor..

Everyone has it's own expertise, I'm a student of pharmacy so I'm good with molecules but bad with circuits
Let's just forget the "splitting of video-signal" for a moment. I will get back to that.
The hardware-design is not completely perfect. If you take a look at commercial products used to detect video-sync, the circuit is far more sophisticated. This is an easy and pretty good way to do it, but it might not be perfect.

The main problem is, that some cameras will need more than 600 mv bias to get the sync-pulse raised above ground. Preferably I would have used a 0.7-0.8 volt zener-diode, but I also wanted to make it as simple as possible - and with standard components. Using a single 4148 diode gives you around 0.6-0.7 volt. While this should be fine for normal cameras, it's not quite enough if you use for example the cheap HK camera. Replacing R3 with a 100K ohm resistor will do the trick, but i'm not a big fan of a pull-down resistor that high. The trick with the PWM signal was just another way to create the voltage that could have been obtained with a zener-diode.

So, the short version. If don't want to "test", I would either recommend Schematic 1 and use a 0.8 volt zener-diode instead of D5, or just use the schematic on page 1.

Be aware that the 50 ohm dimming resistor might be too small. Better give like 100 ohm a shot.
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Old Aug 02, 2011, 05:18 PM
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Quote:
Originally Posted by msev View Post
I don't understand this, so if the signal is split before it arrives into the arduino there wouldn't be any overlay transmitted, so it's split as it goes out of the video out,...could you maybe draw a sketch to clarify?

Also there is a lot of schematics around in the thread, which one do you use (and which is best)? What is the purpuse of other schematics - in simple terms?

I plan to use that dealextreme nano, and the same gps you use so probably no problems in that area, current sensor probably also the same since I won't know how to modify the code if I use the flytron 50A sensor..

Everyone has it's own expertise, I'm a student of pharmacy so I'm good with molecules but bad with circuits
The way these OSD work is different from many other seen in the market.
That's what make them simpler to built.
They detect the video "pulses" and simply inject signal when needed. Kinda writing on top of the existing signal. That is why there is no need to a in/out video line.
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Old Aug 02, 2011, 05:21 PM
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I think that flytron simpleosd works the same.
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Old Aug 02, 2011, 05:28 PM
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Originally Posted by msev View Post
I plan to use that dealextreme nano, and the same gps you use so probably no problems in that area, current sensor probably also the same since I won't know how to modify the code if I use the flytron 50A sensor..
I will change the current-sensor code sooner or later. Right now it's a mess. I have a flytron 25A current sensor that I will test aswell, so no problem if you wan't to use flytron 50A sensor (just write *2 in the code )
I also have a couple of 100A sensor I might test sooner or later (not flytron).
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Old Aug 02, 2011, 05:32 PM
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Originally Posted by Farmer_Joe View Post
I think that flytron simpleosd works the same.
Year, quite a few OSD's work this way. I like that you don't have to run the entire video-signal through your DIY circuit. Worst case - if a connection get's loose you should only loose the text (unless you make a short-circuit).
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Old Aug 02, 2011, 05:33 PM
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Thanks Dennis, hope I'll be able to make it ....Btw I plan to use Sony Bloggie pm-5. Now you'll have some time off from me I'm going for a few days on the seaside, when I come back I'll probably have lots to read since this is such a fast growing thread ..
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Old Aug 02, 2011, 05:41 PM
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Originally Posted by Dennis Frie View Post
Be aware that the 50 ohm dimming resistor might be too small. Better give like 100 ohm a shot.
I mount my first prototype today (schematic of post # 1) and it worked in the first try.

Well done Dennis, thanks!

Now, two "complaints".

1. the dimming provided by the 50ohm resistor is to dark for my liking. I replace it for a 100ohm, still to much darker, I'll try bigger resistances to see if I can get a light grey dim.

2. the characters are to BIG and FAT, is it possible to slim it a bit trough the code?

The arrow works very well pointing home, again, well done Dennis.

Time to play with the hardware and the software
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Old Aug 02, 2011, 05:47 PM
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Originally Posted by jalves View Post
I mount my first prototype today (schematic of post # 1) and it worked in the first try.

Well done Dennis, thanks!

Now, two "complaints".

1. the dimming provided by the 50ohm resistor is to dark for my liking. I replace it for a 100ohm, still to much darker, I'll try bigger resistances to see if I can get a light grey dim.

2. the characters are to BIG and FAT, is it possible to slim it a bit trough the code?

The arrow works very well pointing home, again, well done Dennis.

Time to play with the hardware and the software
Well, as mentioned earlier the GPS-code needs a little update to support more than "around Denmark"
As you live in portugal you can just change a single number to make it calculate LOS correct.

1) The 50 ohm dimming-resistor - year definitely, on my fatshark camera I almost got complete black background. Apparently the HK camera's behave quite different.

2) There is no simple way to adjust/scale the text-size, but it's easy to replace the text with the small font as used for time and text.
I think you can copy at least topline directly from code version 2.

a picture of your project would be great

Did you mounted it in a plane?
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Old Aug 02, 2011, 05:53 PM
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Quote:
Originally Posted by jalves View Post
I mount my first prototype today (schematic of post # 1) and it worked in the first try.

Well done Dennis, thanks!

Now, two "complaints".

1. the dimming provided by the 50ohm resistor is to dark for my liking. I replace it for a 100ohm, still to much darker, I'll try bigger resistances to see if I can get a light grey dim.

2. the characters are to BIG and FAT, is it possible to slim it a bit trough the code?

The arrow works very well pointing home, again, well done Dennis.

Time to play with the hardware and the software
This is small text/numbers;


From one of the first versions. Unfortunately I found it very hard to read in my fatshark googles.
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Old Aug 02, 2011, 06:26 PM
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I use a breadboard and an arduino with atmega328, full of patches, not a beautiful pic to show

I am using a gps simulation program doing a path with local coordinates (in fact coordinates of the rc field I usually use) .

I'll check the LOS calculation trough comparison with other osd.
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Old Aug 02, 2011, 06:40 PM
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Originally Posted by jalves View Post
I use a breadboard and an arduino with atmega328, full of patches, not a beautiful pic to show

I am using a gps simulation program doing a path with local coordinates (in fact coordinates of the rc field I usually use) .

I'll check the LOS calculation trough comparison with other osd.
Can I ask if you are at west or east latitude coordinates? It's made for North / East coordinates at the moment.
I guess the distance calculation on the longitude is too large, a factor 1.4
For now you can just multiply/divide by 1.4 until a more "global" code have been made
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Old Aug 03, 2011, 12:18 AM
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Originally Posted by Dennis Frie View Post
I will maybe make an autopilot in the future - but I don't plan to do anything official. It would be fun to make, but I feel pretty sure existing projects as Ardupilot will be a better choice if you don't want to code yourself.
I did not know this existed. THANKS SOO MUCH!
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Old Aug 03, 2011, 02:03 AM
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So if I'm north and east hemisphere- Slovenia, its pretty good..do i change just one number if i want Slovenia in the center instead of Denmark.. Just how large is the error and which values are affected by it?
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