At 01:07 PM 9/23/2006, Tesla list wrote:
Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
Hi Jim,
I tried that here but with a generic photo from Dan.
http://drsstc.com/~piranha/PIRANHA/Corrected-PetersPictureWComents.jpg
The problem is, with the coil running at like 300BPS, to catch just
the right strike to capture on the scope. If the camera had a
flash "hotshoe" it would be much easier to sync the scope. Having
the scope in the picture too would be cool but the screen
persistence would just make a blur. Digital scopes are no
hope. Even though they can clearly pick out a single hit, they
have a significant digital delay time before the computer decides
to upload the event to the screen.
To get the scope in the picture too, one would have to play with
mirrors to get it the same distance away but in a safe place to
retain the focus.
I was thinking about combining the images in "photoshop" as opposed
to optically. You'd capture a frame on the camera and a matching
trace on the scope. Then, hand stretch and align. The trick would
be if you're automatically capturing a sequence of spinning mirror
frames, then you'd need a reliable way to capture the scope data and
to keep the two sets of data aligned.
There are some ways to do this (for instance, you put a few LEDs in
the corner of the frame that have the current "acquisition number"
(in binary) from the scope data acquisition program displayed on
them. They'll render in the spun image as stripes along the side of
the image. You can then use a program to go look at the image and
read the bits.
I hadn't thought about doing it optically, but with an analog scope
it would be easy.. you just turn off the horizontal sweep, turn the
scope so that the vertical axis is parallel to the mirror spin axis,
and let the mirror do the sweeping.
Steve Conner suggested using an LM3914 or two as a bar graph LED
driver that could just be placed to show up in the picture too. It
would work just like a scope then. But we are not sure if the
LM3914 can operate fast enough (at "least" 100kHz).? If anyone has
tried to run the LM3914 at say 100kHz and above I would like to hear from you!
You could use a software program to go look at the brightness of the
pixels reading the LED, and turn that into a trace?