Build your own embedded DVR

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Hi,

I wonder if someone tell me how to digitize and save/record composite
color video data (and optionally audio) from a low-cost camera into
compact flash or SD memory without using a PC.

I know I can purchase COTS units like
http://nservices.com/wireless3.htm
http://www.brickhousesecurity.com/memory-card-dvr-video-recorders.html
http://www.startechoutlet.com/product_404_detailed.htm
http://www.pimall.com/nais/ultraminidvr.html
http://www.eyespyli.com/dvr9800.htm

But, I want to learn how to digitize and record composite video (as a
hobby).

Thx

Miem


Re: Build your own embedded DVR


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likehttp://nservices.com/wireless3.htmhttp://www.brickhousesecurity.com/memory-card-dvr-video-recorders.htmlhttp://www.startechoutlet.com/product_404_detailed.htmhttp://www.pimall.com/nais/ultraminidvr.htmlhttp://www.eyespyli.com/dvr9800.htm
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Here you go, it's all been done for you with an AVR:
http://www.circuitcellar.com/avr2006/winners/AT3267.htm

Dave.


Re: Build your own embedded DVR


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likehttp://nservices.com/wireless3.htmhttp://www.brickhousesecurity.com/m ...
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AVR:http://www.circuitcellar.com/avr2006/winners/AT3267.htm
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Im very impressed !


Re: Build your own embedded DVR


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AVR:http://www.circuitcellar.com/avr2006/winners/AT3267.htm
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Dear  Dave,

Thank you for your reply and for the URL.
The AVR based image/video capture circuit on that URL is very
interesting.
It use OV528 (www.ovt.com) which is a JPEG compression chip designed
for mobile phones and PDA's. My understanding is that it requires
OVT's digital camera chips.

How ever I want to be able to digitize/capture composite video signal
from any ordinary video source such as low-cost cameras, VCR, etc.

Do you know also any other circuit which can digitize composite video
signals without needing a PC?

Cheers,

Miem







Re: Build your own embedded DVR


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AVR:http://www.circuitcellar.com/avr2006/winners/AT3267.htm
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Sadly, this sort of thing is possibly in the realm of high density
custom IC's these days and mostly intended for the PVR or DVD market.

The only thing that comes to mind was in the late 80s or early 90's EA
or ETI magazine made up a project involving still video frame capture
PC card (probably of XT class).  Because of the technology at the
time, it would more likely have used discrete ICs  and therefore
should be easy to understand as a starting point for how video signals
can be read into a computer/microcontroller and help you to build such
a system for hobby use.

Its very likely that this unit could be interfaced to a modern high
performance microcontroller such as an  AVR - and signals stored on an
IDE hard drive thus avoiding the PC.  (There are a number of circuits
on the web for interfacing HDD's to microcontrollers - mainly for MP3
based projects.)

OR:
You can buy PVR devices (usually with a set-top digital box built in)
starting from about $250 or so at most electrical retailers such as
retra-vision, betta, E-Bay etc.  WES components also sell one.  I
would look for one with a composite video/audio input - or you may
have to use an RF modulator.  A very comprehensive remote control
would also be good, to give you greater control over the functions of
the unit if you want to try and interface it to a microcontroller or
do other experiments with it

What video format these devices store the info on the internal hard
drive is unknown.

I would consider buying one of these units and experiment with it.
Unless you happen to google up some suitable project on the net - this
is probably as good a starting point as I can think of

There will likely be a custom IC that will do all the digitising etc.
Read the part numbers of all the internal ICs and google them to find
out more of how the system works.  It would also be helpful to collect
all the brand/model numbers of the available units, and see if you can
buy a service manual with a schematic for these to help in your
research.

Major long-established brands (especially their more up-market models)
like Panasonic, Sharp, Sony etc should be able to supply service
manuals/schematics hopefully though they might cost a bit to buy.

-------
Another problem you may face in future is that AV may disappear as a
standard.  Proprieteary digital methods (like HDMI on PC's already)
might take over as a standard method of sending video/audio signals,
especially if "copy protection" based stuff starts being implemented
by government regulation.




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