3+km HD FPV system using commodity hardware

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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    • Hey Tobias,

      Looks like these adapters are only available in the UK and don't ship internationally. Any chance I could buy a couple send to you and forward them to Australia? I have long lost family in UK but they are all beyond 60! haha

      Cheers, Jez

      • make it double for me too hahaha

        • I've done a really thorough search and can't find it anywhere else! Surely it's made in the Far East somewhere...CSL seems to be an Amazon UK brand. 

          • Developer

            There are a lot of suppliers using this chipset on alibaba.com.  Including a few that are willing to sell even single units.  These direct prices are pretty low, maybe $8~$15 per piece.  I've ordered from Alibaba before although it was not as easy as ordering from a regular online store (the supplier I dealt with wouldn't accept credit cards)

          • I found this though (same chipset) : http://www2.advantech.net.au/products/1-2R51YZ/EWM-W149P/mod_0A352C...

            http://downloadt.advantech.com/ProductFile/PIS/EWM-W149P/Product%20...(01.15.14)20140122153225.pdf

            Looks like it's available in US/AUS - looks like we'd just need to 3D print a housing... What do you think?

            • How much?
              • $45 AUD per unit + 10% tax. with 2 week lead time. The amazon units would be a lot easier/cheaper! The challenge is out for someone to find an alternative supplier for us non UK/Euro guys! 

                As per Randy's comment just a moment ago, would any adapter with this chipset onboard be likely to function the same??

    • just a little edit: I had to add

      hdmi_group=2

      hdmi_mode=3

      to /boot/config.txt to make it work well with the black pearl tft I plugged the ground pi into. Next step will be to build a facebox with cheap tft and fresnel lens.

    • Is the injection rate comparable to that of the TL-WN722?
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