Reading USB camera data from a microcontroller

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Can some USB, microcontroller expert advise me how can a USB webcam be
interfaced with a microcontroller (PIC, ATMega, etc) so that we can capture
image frames (low speed, low res) with the microcontroller?

 



Re: Reading USB camera data from a microcontroller
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you'd need a usb host on the board to interface with the micro, power to run
the cam from the board... you may be better ripping a cheap cam apart and
pulling a direct video output before the usb out (if possible)

-mark



Re: Reading USB camera data from a microcontroller

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Forget it.
Better just to buy one of the cameras with a video output.
Key thing about USB, is that it is designed to make the 'slave' device
relatively easy to produce. The 'host' device, requires a _lot_ more
hardware and code. It is possible to produce a basic host, but you are
looking at perhaps 5 to 10* as much work as producing a direct video
grabber...

Best Wishes



Re: Reading USB camera data from a microcontroller
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About as well as you could pull a 20-ton cargo trailer up a hill using
a bicycle.  You need a USB host for that, which needs between one and
two orders of magnitude more CPU power than what you're envisioning.

--
Hans-Bernhard Broeker ( snipped-for-privacy@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

Re: Reading USB camera data from a microcontroller
Cypress makes some nice little USB host chips - I'd reccomend taking a
look at those as I doubt a 8b micro could handle the complexities of a
USB host interface. Best of luck!

-M. Noone


Re: Reading USB camera data from a microcontroller

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Go with an older type serial cam or  get a camucam2 or avr cam
or similar.

http://www.cs.cmu.edu/~cmucam /
http://www.jrobot.net /

http://home.teleport.ch/idobson/ using bascom avr
http://home.teleport.ch/idobson/projects/UDP-webcam.htm
http://home.teleport.ch/idobson/start_e.htm

Alex



Re: Reading USB camera data from a microcontroller

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Not a USB solution, but John Orlando and Brent Taylor won 2nd prize
in Circuit Cellar's AVR contest last year with an ATmega8 controlled camera.
http://www.circuitcellar.com/avr2004/Second.html


Re: Reading USB camera data from a microcontroller
USB is a master-slave system. Camera is a slave, so you need a master (USB
host). Low-end micros with USB are USB slaves too.

You need a USB host. It is either built into the higher-end processors or
you need external chip. But this is only half a problem. Then you need USB
host stack, typically found in larger OS, like Linux.

Rudolf

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Re: Reading USB camera data from a microcontroller
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I'm solving this problem with a Linksys NSLU2 (Network storage system).
This device has one ethernet port, two USB host, and 1.5 serial ports.

You can load a version of Linux on it that will handle a webcam.

I am planning on preporoccesing the image there and then passing on
the relevent information to my main processor.

http://www.nslu2-linux.org/wiki /
--
D. Jay Newman
http://enerd.ws/robots /

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