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3+km HD FPV system using commodity hardware

Posted by befinitiv on May 6, 2015 at 12:43pm

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.

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Tags: fpv, linux, raspberry, wifi, wifibroadcast
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Replies

  • Developer
    Randy October 20, 2015 at 11:52pm

    Not sure if people heard but the latest version of Tower supports displaying H264 video.  Fredia is the Tower lead and we discussed this on the ardupilot dev call and we wondered if anyone here might be interested in trying to get it working with Wifi Broadcast?

    DroidPlanner/Tower
    Ground Control Station for Android Devices. Contribute to DroidPlanner/Tower development by creating an account on GitHub.
    • James Wright > Randy November 17, 2015 at 9:15pm

      This would be amazing, perhaps just include gstreamer support! This would add a whole umbrella of HD downlink support. 

  • Tobias Witting October 19, 2015 at 7:16am

    so new alfa 5GHz dongles are here. On the tx side everything works fine and I can inject packets. On the rx side I have no luck. I had wifibroadcast working a few months ago, but for some reason I decided to start with a fresh raspbian.. using either the ALFA AWUS051NH v2 adapters I get the error "DLT_IEEE802_11_RADIO Encap". This is on my pi as well as on my laptop. What could this be? If I create a wifi access point on the receiver and connect the copter pi to it I can stream video fine.

    • Fnoop > Tobias Witting October 20, 2015 at 5:36am

      https://befinitiv.wordpress.com/2015/04/24/using-raspberry-as-a-dis...

      This might help?

      What tx/rx parameters are you using at either end?

      Using Raspberry as a display device for FPV video received via wifibroadcast
      This post shows how video data transmitted using wifibroadcast can be received and displayed on a Raspberry pi — As I have described here the whole w…
    • malkauns > Tobias Witting October 19, 2015 at 9:24am

      Screw 5.8ghz and go for 2.3ghz.  Working wonders for me after I hacked the atheros drivers. Better penetration too. :)

      • Johnatan > malkauns October 19, 2015 at 9:55am

        But what if I want to use Taranis plus with L9R receiver which is 2.4 GHz?!

        • malkauns > Johnatan October 19, 2015 at 9:59am
          I've flown with other 2.4 people around with no problem. Not sure how it would be if I were using 2.4 for control. I'm using a DTF UHF 433mhz module on my Taranis for that.
  • Tobias Witting October 12, 2015 at 9:19am

    thanks guys for the info. Getting the AWUS036AC to work looks a bit involved... so I think I will order the AWUS051NH v2, as you report that it works...

  • Tobias Witting October 12, 2015 at 1:09am

    has anyone tried these? Alfa Network AWUS036AC Long-Range Dual-Band AC1200 Wireless USB 3.0 Wi-Fi Adapter w/2x 5dBi Removable External Antennas for Extreme Distance Connections - 2.4GHz 300Mbps / 5Ghz 867Mbps £28. Maybe worth a try for 5.8GHz? I haven't had much luck with the cheap CSL adapters. Felt promising initially and they work using wifibroadcast but the injection rate is very low compared to the WN722N. I'm still keen, though, to get it working on 5.8GHz. This avoids me having to dig through openlrsng again (it certainly works but it is an additional pain to set up comapred to taranis 'plug and play' RX and TX). But the main reason is to be able to fly with a couple of 2.4GHz TX people around. 2.4GHz for video is not so useful then.

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