LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))

ethan at ethan at
Wed Jul 20 10:00:22 CDT 2016

> I wouldn't be doing that.  I cited the cg6 by way of contrast.  How the
> points get into the display hardware is still open, but a framebuffer
> seems unlikely to be involved.  (I suppose a framebuffer with something
> like DVI-D could be used as a way to continuously replay sequences very
> fast, but it has its limitations.  I'd rather build a hardware ring
> buffer, but I tend towards hardware hackery.)

Ah gotcha. In the laser show world there are gadgets properly called DACs, 
that usually connect to a host computer via USB, ethernet, or in the old 
days parallel port or PCI/ISA bus. They usually have 8 to 24 bits per 
channel, and will have channels for X, Y, then colors (Red, blue, green 
for diode based systems -- or some have a lot more channels as it's 
possible to have different sets of the same color on different 
wavelengths. 445nm blue looks a lot different than the 473nm blue, etc.)

The Etherdream is the open hobbyist ethernet/USB connected device and runs 
around $200. The Pangolin FB3 is Pangolin's USB and the FB4 is ethernet. 
The pangolin units mostly only work with Pangolin stuff when it comes to 
modern DACs but the Etherdream has more hobbyist type stuff using it. 
There is an "industry" pinout for the DB25 called ILDA that specifies the 
color and XY pins, safety interlocks and what not. Some DACs are 
differential signalling for running over longer cables.

The old school Pangolin hardware is called QuadMod boards, so if you find 
a QuadMod card in an Amiga or a QuadMod32 in an ISA PC that's what those 
are. The QuadMod2000 runs on PCI computers, but still approaching classic 
since it was a Windows 2000 product.

Ethan O'Toole

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