RE: New XY Monitors

It seems to me that with some effort to change the appropriate MAME driver,
you could change the vector output to provide not just one stream of vector
data, but N streams of vector data. If we striped the display area into N
pieces then you can split the work load over N scanning units in order to
overcome the scanning limitations of the current device.

Then for a given scanning technology you divide the required number of
points per second for the game by the rate each scanning element provides,
and that tells you how many scanning units you need to display all the
points. You then partition the video output from the driver to equal the
number of scanning devices.

So, even with the laser scanning system talked about here, if you can't get
the performance you need with one scanning system, use two. Split the load
between the top and bottom half, or left and right half. You'll get your
instant speed improvement without waiting for that next galvo to come out.

I haven't looked at the MAME source code so it's hard to guess about this,
but I'll try anyway. At some point the MAME driver should have a vector
draw list that it is about to rasterize. You could examine the end points
for each vector segment at this point in time and do the partitioning then.
If a segment is fully in one quadrant or another that vector is trivially
assigned to the appropriate bucket. If a segment has an end point in more
than one partition, you'll have to break that segment into pieces and put
each piece into the appropriate bucket. Then output your vector list data
as you do today ...

Joel-

Rodger Boots wrote:

> Call me naive, but I was going to get the light source VERY near the
galvos (no more than 1/4") and the galvos VERY close to each other (1/2"
maximum). This would allow the
> galvo surfaces to be very VERY small (can you say minimum inertia?)

for the Laser we use 3mm x 3mm (X-axis Mirror) 3mm x 5mm (Y-Axis) and the
mirrors are less than 2mm away from each other... and I can get what's known
as 50,000pps (about 12k
vectors per second, or 400 vectors per frame at 30fps) if I use 5x5 and
5x8 stock (Usually used for remote fiber Launched Heads) I can do at max
24,000pps minimal inertia
but at these speeds resonance frequencies of the mirror stock, glass warping
and/or shattering become a factor

> and wouldn't be conventional mirrors at all. By keeping inertia low and
movements very small I was
> hoping to use either piezo transducers or those mini-headphone speakers.
Problem there is finding some with high enough reflectivity.

you need something that has a position sensor.. to be able to halt the
mirrors and not over shoot it's target
again mini headphone speakers or piezo you could probably do 20-30 vectors
per second...

>
> Scanning power would be quite low, simple amplifier with no heatsinks.
Possibly (wishful thinking would be more like it) drivable from the game
board without any amplifier
> at all.

look at the amplifiers like on a Wells Garner... you could probably use the
output of that to the magnets easier than the signal coming from the
board....

>
>
> The lamp drivers would be scarier, but I had some interesting ideas for
doing that.
>
> At the present time, a low-cost LASER diode could probably handle the red.
But the <$20 red LASER sounds good, the green beam would be over $300 and
blue just isn't
> available.

some day soon there will be all colors cheap.. every laser company in the
world is working on the blue... it's been made, but they are having a hard
time making it work
consistantly

>
> And there still is the problem with the screen having no persistence.

monitors have no persistance. LCD's laptop screens have some, ever try to
play a video game on a LCD... all you see are ghosts or smearing.
Asteroids and such run at 30-60
frames per second, Asteroids, 60 Frame Per Seconds, there is defiently no
persistance there, or it would look like hell.

>
>
> Now making a vector monitor in the form of a GOGGLE is a whole different
story. Here LEDs would work. Entire goggle could be done for possibly
under $100.

Backlit LCD would work here.. a little 5x5mm color LCD... but you still
need a driver to convert from vector to a pixel based display

>
>
> Robert Mudryk wrote:
>
> > the galvo's in a old Laser player is known as a GAL-2 seen sold on
ebay every once and awhile... best case... you could scan a single letter..
if it was large
> > enough... a GAL-2 is rated at 300 points per second, or about 4-5
vectors per frame... nice for making pretty patterns in laser though :)
> >
> > peter jones wrote:
> >
> > > -----Original Message-----
> > > From: Rodger Boots <rlboots@cedar-rapids.net>
> > > To: vectorlist@synthcom.com
> > > Date: Thu, 16 Nov 2000 14:54:42 -0600
> > > Subject: Re: VECTOR: New XY Monitors
> > >
> > > > I was thinking the "laser bouncing off of galvos" method, but the
problems there
> > > > are getting the costs down.
> > > >
> > > > So then I says to myself "self, how about using very small earphone
elements or
> > > > piezo transducers VERY close to the laser so they don't have to move
much to get a
> > > > LOT of deflection?", but the lasers are still too expensive.
> > > >
> > > > So then, though it's a messy approach, I wondered about using arc
lamps for the
> > > > three colors. Doing high speed modulation should be a nightmare,
but let's just
> > > > see where this thought goes. How much are those arc headlights they
use on some
> > > > cars?
> > > >
> > > > The whole downside to all of this, though, is the lack of
persistence that CRT
> > > > phosphors give you. On the "bright" side, though, explosions could
light up the
> > > > room!!!
> > > >
> > > I was going to try and play asteroids once using a laser-diode from a
pen running past 2 galvo's from an old phillips laser-player but never got
around to building it.
> > >
> > > it was only to project a small 10-30 inch image but it was just an
idea to test the galvo-speed.
> > >
> > > L8r.
> > >
> > >
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> >
> >
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>
> --
> Windows:
>
> 32 bit graphical interface for a
> 16 bit patch for an
> 8 bit operating system written for a
> 4 bit processor by a
> 2 bit company that can't stand
> 1 bit of competition.
>
>
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Received on Mon Nov 20 09:52:20 2000