I’ve been wondering, what would be the easiest way to route telemetry and commands from APM to Internet. Using 3G modem, would provide almost unlimited range (I know there has been some discussions about this in DiyDrones forum. Here in Finland the GSM network is very covering, but due the way the cellular towers are optimized, maximum altitude where the connection works is probably less than 200 m.)
In theory, list of required hardware is not long. One just needs to receive messages from APM and encapsulate them to UDP packets and send via 3G modem and vice versa. Unfortunately handling PPP communications is too large task for simple microcontrollers. I ended up using BeagleBoard for the sake of easy development and since I had one at hand. I realize that BeagleBoard (which essentially is full computer by itself) is an overkill, but it’s not very heavy and fits easily inside Maja’s fuselage. Basically any embedded system, capable of running linux and acting as an usb host would do. Maybe in the future I figure out some additional tasks for BeagleBoard to do.
The setup works quite nice now. Unfortunately I haven't been able to do much flight testing. Weather constantly sucks this winter here in Finland. As you can see I already installed skis, but there's not even snow, even though it's almost new year.
I wrote more detailed post to my blog, with link to sources: http://antibore.wordpress.com/2011/12/28/routing-apm-communications-to-internet/
Comments
Sorry, i forgot the link on my last comment :)
http://www.blackmagicdesign.com/products/videorecorder/
crazy and possibly stupid idea incoming ...
guys, what about using an USB to Ethernet adapter? if such an adapter would work with the Easycap then we could have the easycap driver running directly on the ground station whereas the RPI would just stream the USB communication (assuming the required USB bandwidth for a low res capture would not be too much).
I guess this one would be a nice one, but i don't know if it's supported by RPi OS....
here's a more complex device: http://www.hauppauge.co.uk/site/products/data_hvr1900.html
but its expensive, its heavier and there are no guaranties that it works any better.
@Jerry: I tried but i got those grey lines. I will try your modprobe setting and see if it makes things going :)
@all: I think that the problem is the format supported by the device. When i do a --listformat, Easycap doesn't support MJPEG. Then it needs to transcode the YUYV signal to MJPEG and the Pi has not enough resources to do this. If i use my Microsoft webcam it works fine. This cam DO support MJPG in --listformats. I guess i need another capture device which supports either MJPG or H.264 so the Pi doesn't need to transcode the videostream, but relay it directly. The challenge now is to find a video capture device which support H.264/MJPG AND works with The Raspberry Pi.
How is it going guys?
Tommy, did you manage to get your easycap work with h264 encoding?
I am still waiting on my device to arrive :(
Tommy, did you try this yet?
I forgot the last step in my setup to solve the grey screen with stripes !
You must to load the 'easycap' driver with 'bars=0' as options !
To do this properly, create a file into '/etc/modprobe.d' to specify the driver's options :
sudo sh -c "echo 'options easycap bars=0' >> /etc/modprobe.d/easycap.conf"
And reboot your RPi ;)
Sebastien
Btw: I have the same problem as you with the green screen and the grey with stripes. But using PAL_M i get a short picture from time to time.
Looks nice, but the goal must be using a video capture adapter. This is because people want's to use a camera of their own choice. I prefer to use Gopro Hero2 so that i can record everything to my SD card in HD at the same time streaming it to my GCS via 3g.
Maybe this will be helpful? Should go on sale this month for 25$
http://downloads.element14.com/raspberry-pi-camera/?COM=rpicamera
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