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Project Help and Ideas » A "Simple" approach to de-wiring a wired webcam??

March 21, 2011
by Twarter369
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I am trying to take a wired webcam (USB) and put it on a wireless transmission. The range is going to be short. Less that 200 feet at all times. I came across this on a similar discussion

"just give the cam a 5V power and connect the data wires to FM transmiter then connect a radio tuned into that station to your computer via a home-made earphone jack to usb connector"

First off does this sound feasible. If I built a USB stick with an RF receiver attached to the data lines?

Now I have built a simple RF circuit before using 6 turn coil. It was really reliant on Battery voltage. I have been told using a Air Trim Cap in the right FM bands will give me a steady freq. independent of my Vcc, correct?

So, I guess it comes down to: would sending USB signals across RF confuse the data pins on the receiving end?

March 22, 2011
by Ralphxyz
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Sounds like it "should" work. One the biggest problems with home-brew RF projects is interference. Your RF might interfere with unknown appliances, some of which might not be tolerant of your interference. Using a commercial FCC approved module sometimes is better, though admittedly not as much fun.

I have a ZigBee Xstick (USB/ZigBee) and some ZigBee module/breakout boards just waiting for me to get around to putting together a project. ZigBee might not have a great enough data rate as you might need for a Web Cam but Sparkfun has some RF modules that others here in the Nerdkits forum have used. Data rate will probable be a challenge especially with a home-brew project. You might need to use bluetooth modules.

Ralph

March 22, 2011
by Twarter369
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I agree. Using the Zigbee Comm network would probably be easier and more reliable. However, I am confused how those various components work together. For instance how could I use the multi-point (802.15) XStick to connect a camera to my computer via the network? It seems, at the very least, that I would need a Male to Male USB adapter so I could plug My Camera's USB into the XStick, correct? Which would then make my camera appear as another device connected to my network? That i lose it. How would I then connect my computer to the video feed?

On a separate note. Thank you guys for all your help! Everyone on here has been super helpful and informative. This has to be one of the friendliest web communities left!

March 22, 2011
by Ralphxyz
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First of all the I do not know the "multi-point" XStick. My Xstick is just a single USB A, it plugs into a USB port on a computer or USB hub.

Your camera has to "plug" into something that understands USB, there has to be a USB driver somewhere that knows what to do with the signal even before you try to communicate.

One way to do "Wireless" web cam is to use WiFi, again you need a computing module that understands USB that also understands WiFi.

When you orignally said "I am trying to take a wired webcam (USB) and put it on a wireless transmission. "

I thought you were speaking of having your camera wired to your pc, with your pc wired to your Nerdkit and from the Nerdkit you wanted to do your RF (wireless) communications.

That is all doable (but not necessarily easy).

If you want to make a true wireless camera then you still have to connect your camera to some sort of computing device that knows how to communicate wirelessly.

It might be easier to buy a wireless camera.

Ralph

March 22, 2011
by Twarter369
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LOL, I guess I need to work on my explanation of projects. The Webcam has a Wired Male USB adapter on a 4 pin head (board side). I want to plug a module in that replaces the wire. I liked the RF idea because: a)Trimmers on the sender and receiver would allow me to fine tune the frequency for different areas. b)It is pretty damn easy to generate RF by comparison. c)There is no need to have a wifi network available. I want to be able to pop the same unit into an off road R/C and take it into the woods with just my laptop.

It is a pretty generic cam but it is tiny and would fit perfectly in most RC cars (provided I kept the RF components relatively small as well). Like you mentioned Transfer rate might be an issue. I don't know what the Transfer rate is for my cam, or how to tell what it is for my RF circuit either.

Okay here is my working theory for Sending a (possibly crappy)USB video wirelessly using RF. The cam plugs into a RF Transmitter. The transmitter used the Data +/- as Signals ( I can amplify this signal if need be) to transmit. There is an FM receiver on the same freq. That has its Signal lines connected to the Data +/- of a Male USB.

The computer SHOULD be able to use any software that could have detected the cam plugged into the USB previously.

Possible problems include transfer rate and noise interference....Sound about correct?

March 23, 2011
by Rick_S
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Keep in mind, USB is a two way timed protocol. The delay's you'd get sending a hopefully clean signal across radio waves both ways would probably kill the timing altogether. Let alone, you'd have to make sure both could send/receive at the same time without interference. You'd have a better chance of sending the raw camera data to the camera logic board, but even that would be quite a challenge.

I don't mean to burst your bubble, but I don't see this as nearly the simplistic task you are visioning.

Rick

March 23, 2011
by SpaceGhost
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I have thought about wireless web cams myself. I have in mind a sort of different approach though from what you have in mind.

First of all, I do not think you would be able to transmit the data signals with a common FM "wireless mic" type transmitter. Like Rick mentioned you would need two way communication, and I just don't think you would have enough bandwidth. I would Google the idea maybe to see if anyone else has tried this - But I think you may at least find some solid explanations for why it wouldn't work.

What I have considered doing uses a small camera module with analog outputs (these have RCA type jacks for audio/video outputs). Wire this camera to a miniature 2.4 GHz transmitter. You can cut off the jacks and hardwire the modules together, usually through capacitors on the inputs.

These 2.4 GHz transmitters pair with receiver modules that have analog outputs. Now, if one was to connect the receiver module to an A/V USB adapter...

I have seen quite a few of these USB adapters on the web. They are usually used, or marketed for people that want to make digital backups of home movies, etc... Not for copying copywrited VCR tapes, of course! ;)

I've seen these USB adapters that make use of analog audio and/or video in a wide range of prices... From very cheap to pretty expensive.

I have a few 2.4 GHz transmitter and receiver modules - they are fairly cheap and documentation is easy to find on the web. They are a lot of fun to play with, and I've done a few interesting projects with them. I've used them with little (cheap) cameras, and to re-transmit audio & video from our satelite receiver out to the garage and basement... Gotta change channels in the house, but hey I get satelite TV in the garage!

But I don't have the USB adapter. Like I said, there are LOTS of them out there.. I'm mainly unsure what to buy in terms of what type of software (what you can do with it) that comes with these adapters. All are meant for video capture, of course.

I'm sure an ideal device is out there though. If you decide to research this option, I would be very interested to hear your results.

BTW, the commercial 2.4 GHz transmitter/receiver packages for "home security" are WAY overpriced. You can put something together yourself using the raw modules MUCH cheaper. I can offer you some more advice in this area, if you are interested.

Dave

March 23, 2011
by Twarter369
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Got it. The FM band doesn't modulate fast enough I need at least VHF but will probably end up with UHF, right? The minimum I saw that was acceptable was 1.4 GHz and that was crappy black and white video at approx 200m. The range depended on the operating voltage. I need a some advice on this project. Here are the constraints I am working with:

Camera/Sender needs to be small and light enough to fit in a 1:28 scale R/C car. The video needs to be clear and color(I have a video signal amplifier to help here.) Receiver needs to be able to interface with a Laptop so the video can play on most computers.

w

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