Build your own embedded DVR

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

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

Thx

Miem

Reply to
Miem
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Here you go, it's all been done for you with an AVR:

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Dave.

Reply to
David L. Jones

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AVR:

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Im very impressed !

Reply to
kreed

AVR:

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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

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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

Reply to
Miem

AVR:

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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.

Reply to
kreed

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