By putting the OSD information in the video on the ground it will remain on the display if the video from the transmitter is interrupted. Also when the Tx signal gets weak the OSD info will remain clear.
How would you go about getting the Mavlink data out of the ground based Xbee to the MimimOSD?
Right now I have a XtreamBee USB adapter on the ground. Can I just change that to a FTDI board (same one as airborne), parallel the data between the MimimOSD and a FTDI to USB cable? Will Tx/Rx lines need to be swapped? The USB cable would then plug into the computer running the Mission Planner.
Any help is appreciated.
I've been playing round with this a bit more this afternoon and have made some more discoveries. Basically, the OSD chip works, the problem is somethign to do with my video Rx. If I put the output from a DVD player into the MinimOSD, I can overlay flight information from my plane just fine. However, when I plug into the output from my Immersion RC Duo5800v2 receiver instead of the DVD player, I only get video and no OSD.
There must be something different about what my Rx is outputting vs a normal PAL DVD player. I have a PAL video camera on the plane, but I don't know what the Rx is doing with the video before outputting. I need to keep investigating.
So it's fine if I want to watch Top Gun under my OSD, but useless for actual video from my plane :)
Thanks James. This is the information I am looking for.
So it seems you are using a FTDI adapter board on the ground where I am now using a USB adapter board. And then you are using a FTDI/USB cable to the mission planner. Thats what I was thinking. Then all I really need to do is buy another FTDI adapter board for my ground based Xbee.
I can't shed much light on your problem. Make sure all your components are set to PAL and one of them is not NTSC. Make sure the default format is selected on the OSD via the solder pad so it does not auto-select.
That's good news. I am encouraged that someone else has this setup working. I can see a big advantage in making the OSD independent from the onboard video transmitter. You could fly the plane back, IFR if you will, in the event of video link loss. Of course the APM gives you other options in an emergency, but you can never have too many options. It is also one less component to carry onboard and power up.
Today I was able to bench test this setup. Using an XtreamBee FTDI adapter on the ground, I paralleled the data to the Minimum OSD and the FTDI/USB cable. The USB cable fed the computer running the mission planner. I did have to roll the Rx wire on OSD to get the both the OSD and mission planner to respond properly.
I discovered another limitation that may make putting the MinimOSD on the ground a moot point. As the video signal from the plane gets weaker the MinimOSD will blank the OSD information from the display. If the video from the plane completly goes away, then the OSD info shows up on a black screen. I can only guess the MinimOSD can not frame both the data and the video if the video starts getting weak. Without adding more video processing hardware on the ground, the MinimOSD is going back on the plane.
Now that I have used this setup some more, I am also having this problem. Any loss of signal quality means I go to a black screen, not even static.
I continue to get strange dropouts depending on the darkness of the backgrounds I am looking at. Putting it back in the plane is shaping up to be the better option.
I have put the OSD in my plane and most of the problems I had have gone away. Even works with my higher resolution camera. I guess the signal coming from the Rx is a lot less stable than it looks on screen.
Oh well, Ground based OSD was a nice idea but I guess this is not the way to do it.
I feel your pain! Back in the plane......it goes.
I am in the process of selecting components for my system and was zeroing in on the video system from Range Video. Their package price seems to have come down, but the camera resolution is given as 600 TVL. After reading this thread, it sounds like I might have trouble using this with MinimOSD. Do you think that's the case, that it won't work?