Jump to content
Sign in to follow this  
quinndexter

Hows this for simple?

Recommended Posts

I have a cheapo DSE Dolphin Digital/Shortmovie Camera, which when connected by USB, can act as a Livefeed. I was thinking about the hacks of Bluetooth Class 1 Antennas (sometimes extending range x 3, ie 3-400m L.O.S.).

Now - this, in conjunction with BT Class 1 Cable replacers from:

http://www.datasoft.se/bluetoothserialportplug.htm

might produce an immediate, Computer receivable video stream.

Now bearing in mind that the actual capability of my camera is the terrible 320x240px, if you were to grab a more capable 640x480 apple isight or any webcam really, jack the usb Power lines with a pack, voila! Wireless short range, for about $190 USD.

Am I missing anything gentleman?

Many will probably scoff at my theory, but I want to outfit an Electric Heli for short-range recon missions, and many of the answers seen here wont even get off the ground with a leccy heli im sure.

Any input welcome.

Share this post


Link to post
Share on other sites

Well, one first issue is that you cannot connect a USB device directly to a bluetooth dongle, even less to a serial converter. The camera will only work if connected to a USB host.

Also, USB (1.1) transfer rate is 12Mbps, which is needed in order to transfer live 320x240 video. Much more is needed for 640x480. Bluetooth is limited to 1Mbps when signal is strong...

Edited by Kilrah

Share this post


Link to post
Share on other sites

thanx kilrah, i wondered about bandwidth, but please check the link, this is not a dongle, it replaces the need for a cable by special means.

Share this post


Link to post
Share on other sites

Yes, but it's meant to replace a RS232 serial link up to 115kbps, not USB...

Share this post


Link to post
Share on other sites

OK, OK, I kneel humbled Kilrah. My mistake.

I've just been looking at 3G, and GPRS modules for compressions/transmission, being in europe, maybe you can shed some light on wether that's financially viable for streaming video?

Share this post


Link to post
Share on other sites

We do have 3G, but it's still pretty new. I lack precise technical info but according to some discussions I had, with its 384kbps it should be sufficient to transfer a relatively low quality feed. The problem that might appear is a relatively long lag due to the different buffers used between the different stations. For video on demand like some providers offer that's not a problem, you can easily buffer 5 seconds of video on the mobile device. Now to fly a plane...

Another issue is that for now only cities are covered. Pretty problematic as that's not the best place to fly ;)

And for now the prices are totally prohibitive. They are based on data volume, if I do a quick calculation at full bandwidth (48kb/s) that would cost... around a mere $0.40 per second!

Unfortunately, even that many new technologies are now available... I haven't seen any that would beat the good old analog link yet :(

Share this post


Link to post
Share on other sites
Unfortunately, even that many new technologies are now available... I haven't seen any that would beat the good old analog link yet

I think that Wireless Cameras (e.g. 802.11g WLAN) might be an alternative if you have a plane that can carry the weight. As I see it at the moment you would only need a laptop with a WLan Card to go on the field (and maybe an access point with an extra antenna for link quality) and then mount the WLan cam on the plane (need to setup the wireless lan network at first). There are versions that do 640x480 at 30 fps (the more fps the better when flying) as an MPEG4 downstream (several KBits/sec, no problem for your > 1GHz laptop). If have no experience yet with that setup and have no idea what happens for example when the signal is lost. Maybe the image will just stand still until it gets another frame. The newer digital video codecs should be able to handle unstable connections, since they are designed to. This might of course not be a good option when you want to fly with that image as a cockpit view alone. Analog will be better then, better to have a bad quality image than no image (especially when landing ...).

What do you think?

Martin M.

Edited by ma_meister

Share this post


Link to post
Share on other sites

I think there might be a possibility, but we won't be sure until someone has tested. That's something I might do in the future.

I must say that with the experience I have with computer WLANs I'm not very optimistic though. The problems in my opinion are the varying link speed and possible lag in the video encoder/server. I've already had such a hard time finding a simple PC video capture card that wouldn't have an unusable display delay...

Definitely I think the external access point or whatever WLAN peripheral with an external antenna connector will be needed. Or then simply use an antenna with a MMCX connector (I believe) as most notebook internal WLAN adapters have such connectors. One could connect a directional antenna to one of them and so gain some range. Omnidirectivity at short range would be provided by the second internal antenna as these cards usually use diversity.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×