Hi
Over the last couple of months I have been working on a project that might be of interest to you: https://befinitiv.wordpress.com/wifibroadcast-analog-like-transmission-of-live-video-data/
Basically it is a digital transmission of video data that mimics the (advantageous) properties of an analog link. Although I use cheap WIFI dongles this is not one of the many "I took a raspberry and transmitted my video over WIFI"-projects.
The difference is that I use the cards in injection mode. This allows to send and receive arbitrary WIFI packets. What advantages does this give?
- No association: A receiver always receives data as long as he is in range
- Unidirectional data flow: Normal WIFI uses acknowledgement frames and thus requires a two-way communication channel. Using my project gives the possibility to have an asymmetrical link (->different antenna types for RX and TX)
- Error tolerant: Normal WIFI throws away erroneous frames although they could have contained usable data. My project uses every data it gets.
For FPV usage this means:
- No stalling image feeds as with the other WIFI FPV projects
- No risk of disassociation (which equals to blindness)
- Graceful degradation of camera image instead of stalling (or worse: disassociation) when you are getting out of range
The project is still beta but already usable. On the TX and RX side you can use any linux machine you like. I use on both sides Raspberrys which works just fine. I also ported the whole stack to Android. If I have bystanders I just give them my tablet for joining the FPV fun :)
Using this system I was able to archive a range of 3km without any antenna tracking stuff. At that distance there was still enough power for some more km. But my line of sight was limited to 3km...
In the end, what does it cost? Not much. You just need:
2x Raspberry A+
2x 8€ wifi dongles
1x Raspberry camera
1x Some kind of cheap display
Happy to hear your thoughts/rebuild reports :)
See you,
befinitiv.
Replies
Hi all
I got my wifi modules today and made a test. It's working perfect with almost no latency !! :)
Which ones did you get?
Also integrating mavproxy but having issues with Mavconn no pkg for it installing gcc cmake lib are slowing down my PI and increasing delay in video :(
Hallo befinitif
any thoughts about this: TP-LINK Archer T2UH
It is the same form factor as TP-LINK TL-WN722N BUT : its 5.8 ghz so it will not interfere with most 2.4 rc controls, but uses MediaTek MT7610U
Thank you for your time.
PS: would you consider selling disk images for your program ? A lot of us like to play with our toys but are not good software expert and find it difficult to compile programs...
MFG
Has anyone been game enough to purchase them and test them yet?
Ordered them, if anything else I shall use them with @Patrick Duffy method...;)
I'm also interested to hear if the 5.8Ghz dongle works. Just removing the potential interfence with the regular RC would be great.
A number of people on the dev team know how to set-up dronekit and/or mavproxy on an RPI (it's on the wiki here) so that it becomes a "companion computer" and can communicate with the pixhawk. Then someone (maybe me) could help with passing a message back from the ground (via a telemetry radio like the 3dr radios) to change the video resolution. We could use a CONTROL_LONG message with a MAV_CMD_VIDEO_START_CAPTURE method which includes a couple of fields to set frames-per-second and resolution (see this wiki page). ..a bit of a future step but just want to make the offer.
Check this link:
http://ubuntuforums.org/showthread.php?t=1242285
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