I keep asking myself why this cannot be done, and so far i have not found an answer i can believe. So i bought a commercial HD Video/Audio sender for home use and plugged in my gopro as a video source, and my flat screen TV as the player, and i connected up these devices and viola..! it worked. So my next thought what is the problem with making this work in a UAV , it is using 5.8Ghz it is cheap to buy, just need to hack it so the antenna is less directional, and we can then have HD in our goggles, or on our screen.
This would be far more preferable to me for a first time FPV flyer as the picture is so poor at 480x240 pixels, you can hardly see if your moving or not.
What do you all think? i know a more elegant solution would be nicer but for now it would work.
sample of what i meant : http://www.maplin.co.uk/wireless-hdmi-video-sender-kit-503801
Comments
Oops. I meant to edit my post... not delete it
I am sure it has nothing to do with the fact that it costs 20000$.....
The raspberry pi camera module was just released. It can do 1080p@30fps and with a wifi adapter (2.4 OR 5.8) it can stream as well. Set up the pi as an access point an then use gstreamer, or
raspivid -t 999999 -o – | nc [insert the IP address of the client] 5001
as suggested on their blog. Not sure what the latency/range will be, but it's cheap enough that I am going to find out.
http://www.cavium.com/PureVu-3D_CNW5302.html
This is the best option I know of so far for streaming low latency h.264 using standard Ethernet/WiFi.
On paper it looks very promising and has adaptive bandwidth management, which is critical to get robust low latency streaming in for real world applications.
There are several thing you can do to make your GCS more efficent:
1. remove bandwith limiter in Windows: https://www.youtube.com/watch?v=YGrLEyK-b6E
2. Increase frame size for TCP packets. (make your GCS recieve more amount of data before sending an acknowledge back)
3. Use the right hardware. I would have used this combination:
- In aircraft:
This camera has USB-Wifi connector: http://www.aliexpress.com/item/720P-HD-IP-Camera-Module-1-0-Megapix...
http://www.amazon.com/Alfa-AWUS036H-802-11b-Wireless-network/dp/B00...
http://www.l-com.com/wireless-antenna-24-ghz-7-dbi-desktop-omni-ant... (Without the magnet of course)
Maybe even an 2watt amplifier running on a 6v BEC: http://www.radiolabs.com/products/wireless/wireless-inline-amplifie...
- GCS
http://www.amazon.com/Alfa-AWUS036H-802-11b-Wireless-network/dp/B00...
Some satellite dish high gain antenna on a tracker.
https://www.youtube.com/watch?v=LcTKLO0sCaY
And if you want to use your Gopro onboard the aircraft you can use this module connected to the Alfa USB Wifi device: http://www.aliexpress.com/item/720P-CMOS-CCD-IP-CAMERA-MODULE-suppo...
@KayFricke,
"H.264(AVC) with baseline profile at 1080i@25 would mean a video bitrate around 9500 kbps." - i've been using teradek at 4mbps 1080i50 and it was really good quality (that's not my words but TV-guy)
"250m my be extended with a focused signal, but i think the hardware to drive the targeting for a focused signal is way out of our league." - DIY antenna trackers are available and cheap, which makes it possible to use very narrow-beamed antennas
"The second option would be trying to use a gsm module, and surf the existing cellphone infrastructure, but that would be only feasible if such infrastructure exists." - in 99% of the cases you're filming in either nature (no gsm coverage) or highly populated places - stadium, rally track etc - where gsm network is overloaded during events. gsm is no-go except you have good relationships with operator and they'd provide you guaranteed QoS (highly unlikely)..
@Luke Olson, do you have any idea how much do they ask for such TX? and i'm not sure i catched, what would be interface on receiving side - similar receiver with HDMI output or ... ?
Another factor to consider are the regulations surrounding maximum transmitter power. For example, in Australia the maximum limit for 2.4/5.8GHz Wifi is 4W max EIRP (from http://www.comlaw.gov.au/Details/F2011C00543). This can severely limit your bandwidth/range options.
This is another factor to consider when developing/commercialising an FPV device.
Like others have pointed out there are limitations to what is physically possible, however there are long range, low latency, HD resolution video transmitters out there that could be used on a drone. Like I said in a previous comment, you get what you pay for right now. Here's one example of such a product.
http://www.airborneinnovations.com/ai/?page_id=369
In time the technology used for devices like that (and similar like the Bolt or Arrow) will come down in price and "clone" devices will show up on the market. The original poster is probably looking for a $100 transmitter capable of HD video like you see the SD video transmitters at Hobby King. Unfortunately such a device doesn't exist in that price range (yet).
Let's see if i have my math right ...
HDMI used in fpv would mean you would need to be able to stream something like:
H.264(AVC) with baseline profile at 1080i@25 would mean a video bitrate around 9500 kbps.
So the frequency chosen must be 2.4GHz or 5.8GHz, as the lower bands open to us, do not deliver enough bandwidth.
Because of the High Frequencies (0.125m and 0.05m Wavelength) we have a strong signal degradation by obstacles and humidity/rain, and the upper bounds of allowed signal power (100mw as of ETSI in europe).
We are facing a limited range with a diameter around 250m until signal loss in normal conditions (2.4Ghz WiFi 802.11 n), if in line of sight with no obstacles.
Around 240Mbps max bandwidth, so we have within the range enough reserve for a stable stream.
250m my be extended with a focused signal, but i think the hardware to drive the targeting for a focused signal is way out of our league. So a good antennas are our way, but still the gain is not enough for long range flights.
So one option may be adapting the way military extends their range, with relays, we may learn from that. okay, no satelites, but using a second copter, a ardu plane or a weather balloon / blip as a relay bridging our network may work too.
The second option would be trying to use a gsm module, and surf the existing cellphone infrastructure, but that would be only feasible if such infrastructure exists.
Last but not least, get an amateur ham radio licence and register a mobile station. you'll get a call sign too.
For any skipper, your SRC Licence could work too, depending on your local radio reg.
"how far did it go" should be instead of "how long did it go" :)
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