I'm building a project (an ROV) and I'd like to use a cheap webcam for video. I'd like to use 3 small-gauge wires for control - ground, a serial control line, and a return line for the camera signal. I want to be able to display the video on a Linux laptop. Is there documentation somewhere, or some kind of tutorial showing how to use the video signal from a webcam?
That's a matter of figuring out how to use that camera with linux? For video, you can't just use any old wire, need to use proper wire for the type of signal your camera creates, since it's usually high frequency and will need shielding.
You're not planning on piping the video through the Arduino, right? Can't do that, at least not with a "normal" avr-based arduino board. A 16mhz AVR just isn't going to be able to handle a video stream.
I'd be inclined to use the Arduino just for the mobility platform, and communicate with the camera over WiFi, instead of hard-wired (also, it's then easier to convert to true wireless operation, with a wifi adapter on the Arduino and a web interface to control motion...)
Is there documentation somewhere, or some kind of tutorial showing how to use the video signal from a webcam?
I've run analog video over cat3 telephone wire. You would need a digital capture device for the pc like below.
Cool, so I'm assuming somewhere in one of my webcams I can find a video signal line & I can run that & a ground to the yellow connector? Will there be an issue using the same ground for my serial control line? The ROV is going to be pretty small & I'd like to use a 3-wire ribbon cable, like the one a standard servo uses...if I have to use a normal NTSC (or whatever) security camera, or one from an old camcorder, I could do that as well I guess...
For further elaboration, the arduino wouldn't be handling the video signal at all - it would be used for the serial commands to control a servo & a couple of thrusters. A laptop would display the video & take keyboard inputs & send the proper serial commands to the arduino through the 3-wire cable. I'd be happy to post pics of the final project when it's done, including code & details of the wiring.
Whether you’re able to get a usable analog video signal out of the webcam depends on the exact model of the camera. Many webcam video cameras nowadays are totally digital, and never generate an analog video signal, and can only be accessed via USB (for that kind of “webcam”, the kind you use with a computer and take your clothes off in front of), or via IP (for WiFi/network “webcam”).
You need to carefully investigate the capabilities of the camera and make sure that it can output the video in the form that you need.
As I said above, for an ROV, assuming the sizes worked out and all, I’d use a WiFi camera and then, I’d have less to do when I decided to make the ROV fully wireless Of course, if the ROV goes underwater, wireless is a no-go
I'd suggest you do a google search on the "ONVIF" standard for video cameras. You can find Wifi cameras compliant with ONVIF for around $50 and then that camera would be accessible via a separate application through linux, your phone, etc. If you pay a little more you can also get pan/tilt options.