>Jens Dyekjfr Madsen wrote:
>>
>> Oyvind Kaurstad wrote:
>> >
>> > Hi, all.
>> >
>> > I'm planning to make a video capturing device using a PIC
>> > and a PC parallell port.

There's a project you'll be able to find called "Dirt Cheap Frame Grabber"
that actually works. It's not spectacular, but you can capture video at
about 15 frames per second with 12 levels of grayscale. I was able to tweak
the program and my computer enough to get images about 150 x 110 resolution.

It basically used a resistor ladder and a quad comparator to make a 2 bit
flash converter, and used a few of the output pins on the parallel port to
scale the reference on successive passes to get more A/D resolution.

BTW, it used no pic, just an LM 339 comparator, a transistor or two, an LED,
and a few resistors and capacitors.

If you used a pic, you could sample faster and get more horizontal
resolution. If you did it right and counted lines, you could probably
capture a line into the PIC, then dump it to the PC(while missing 10 lines
or so), capture another line, etc. It would take about 1/5 to 1/2 second to
get a complete picture.

You'll need a pretty fast A/D converter. Maybe you could fake it with an
LM3914 bargraph IC?

Cheers, Bob