XBee and video streaming

Preamble

Can the XBee, and more specially the XBee 868, be used for video streaming?

The question

Following on from the XBee 868 blog, the Stack Exchange question, Drones and camera streaming asked a good question.

My answer included:

From x-bee for video transmission?

The data rate is a non-starter. Xbee is designed for serial communications at a max of 230kbps. That’s too slow for any kind of decent video

and

2.4 GHz Xbee products as well as 800 MHz products have data rates below 250kbps.

Mind you, this, again, all depends on the video quality that you require. The thread Can you use XBee to transmit video? points to a Wikipedia article, which states:

Video

  • 16 kbit/s – videophone quality (minimum necessary for a consumer-acceptable “talking head” picture using various video compression schemes).

Another thread, XBee on Society of Robots, notes that the XBee’s 250kps is half duplex, so that actual data rate is only ~125kbps. So, it would depend on the data rate of the camera that you wish to use.

Looking further into the subject

Articles that say “No”

Instructables – video over xbee

Using XBees to transmit video isn’t practical, they dint have a fast enough data rate unless your going to have a .1 megapixel camera. it wont work. but still photos once a second might. sparkfuns serial camera (http://www.sparkfun.com/commerce/product_info.php?products_id=9334) might do the job with a 6 mile xbee (http://www.sparkfun.com/commerce/product_info.php?products_id=9097)

Instructables – Can an xbee send live video streaming?

I doubt it, the bare channel capacity is 250k, with the overhead probably < 200K

A couple of people say “no” here,Solution for sending Wireless video back to ground, xbee alternative?, however, see the “yes” section below

Arduino Forums – Sending a video feed over xbee?

Arduino Forums – Can XBee Pro 900 be used for RF control and Video Stream?

Arduino Forums – Sending Video to PC via Xbee?

Articles that say “Yes”

Well, it is more of a maybe, Live video streaming for remotely operated robots, solutions?

A solution not using XBee

One chap has achieved acceptable video transmission, using a 900 MHz XBee, here, with proof, Solution for sending Wireless video back to ground, xbee alternative?

Try the 900MHz versions if you’re using a 2.4GHz reciever. The only thing you have to worry about is the proximity of the video transmitter to the processor. All video transmitters can interfer with main processor function because of the intermediate frequencies within so location is important. I found that greater than 4 inches from video transmitter to processor edge is a good start. I mounted my on a piece of alumimum stock for strength and to sink heat.

900MHz is actually better than higher frequencies if you fly in and around things like trees. The higher the frequency, the less tolerant to incidental “line of sight” interference. They are also cheaper.

I use a 500mW 900MHz system and I have no problems. I modified the video reciever as described in the guide section of rcexplorer.se. David is a dedicated FPV flyer and has gone to great pains to document his work.

I purchased my video transmitter from Range Video. The 500mW transmitter is no longer available but Vova’s got a 800mW version on his web site. 800mW is kind of a miss leading because the voltage of the source determines the power output. $65.00 for a transmitter is not bad. He’s got a multiple channel reciever that will work but multiple channel recievers are generally less sensitive resulting in reduced range. I picked up a single channel reciever at Ready Made RC. I saved a few bucks (only $50) and I was able to update the sawtooth filter to improve the range even more. I’ve not flown my quad more than about 200 yards using this setup but it’s been almost glitch free. I plan to use a Go Pro in the future but for now I use a hobby king camera I got for $17 (it was on sale so I added it to an order). The hobby king camera is fine but the lens is not a wide angle. If you don’t have a wide angle lens it’s kind of like navigating in a tunnel. The Go Pro will be a big help.

I’m not interested in transmitting HD to the ground. That’s too expensive and really impractical. Again, the Go Pro records the flight just fine and it outputs to the video transmitter in real time. My system now is standard NTSC video (510×492).
I picked up a head tracker for Range Video ($55) and will use it with to-be-purchased video goggles. I’m not sure which system I’ll use but resolution is key. I’ll probably use the Headplay 800X600 system. Later, I’ll add OSD, a patch antenna and probably a tracking system.

GPS telemetry from an aircraft is required to have an recieving antenna “track”. In simple systems, data is transmitted via the audio channel of the video transmitter. On the ground, the recieving antenna is gimbaled toward the transmitter by decoding the downloaded GPS data. Keeping a patch antenna pointed at the aircraft really improves range. I’ll probably use the EZtracker and Tiny Telemetry from Ready Made.

I hope this helps.

www.readymaderc.com

www.rangevideo.com

Cheers, Scott

 

 

 

 

 

 

Advertisements

3 thoughts on “XBee and video streaming”

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s