Topic: Exactly why this forum exists

[BlinkenLights]

its TTL only..
and just wait for the 8 channel boxes to be done...

[Fanny Pack]

Doesn't matter that it is TTL.  It's on Ebay and is being marketed.  The sound card solution is a word of mouth solution.  Who's selling it?  Where's the website for it?  Who's in charge?  etc etc etc?  Sound cards COULD be a driving force but until they are made a more complete kit, or prefabricated, with detailed easy to follow instructions it isn't going to be taken too seriously.  I used to be all for the sound card solution.  That's how I got started in this.  That's one of the driving forces for Spaghetti.  Finally DrLava made a driver and I was like "COOL!".  Then I went to build one and all I had was some pictures and some info scattered about PL. I finally got it soldered up and I had some bad connections and I finally fixed those.  Then I spent a day with an oscope and windows settings trying to get it to put out a stable image.  Then i switched USB ports and my voltages were all off.  Not to mention that the outputs are unbalanced and not the full +-10v that most scanners expect.  So, there are a LOT of obstacles to be dealt with when using the sound card.  All of these issues can be overcome but I don't see anyone taking the lead on it.  I tried to persuade James or someone to write up some documentation on here on how to configure it in Windows and it didn't happen. 

Anyway, I think you know what I am saying.  The solution works but it isn't an easy solution and most people have enough problems to work through so saving $50 or so might not be worth it.

I encourage James or DrLava or whoever to take it to the next level, though.  Come up with a complete kit with some easy to follow instructions.  Put it on  Ebay... whatever. 

[BlinkenLights]

i agree. i have been saying that it needs to be an easy product for a while..

James wants people to learn what the hell they are doing, i say make it easy for them..

We will never agree on this because james is hard headed.. smart, but hard headed

[Absolom]

I would agree with Hyena.  I built a correction amp from scratch on some perf board.  I was lucky enough to have it work the instant it was fired up.  What took time was tweaking the pots to 0 my idle output.  Even with 20 turn pots, it took a little finesse.  And then if you switch computers, ports, things like that, just like Gary says, you have to readjust.  Most of us here are pretty tech saavy and can make it work, but most people who are not that tech saavy just want to plug it in and have it work.  I have even noticed offset changes from when my laptop is plugged in and when it is running on the battery.  

We need a website with everything on it.  Schematics for those who want to build one of their own.  Full tech specs for the prebuilt ones.  A complete setup manual, both online and PDF, and a troubleshooting page with tips and tricks.  This website can have an order form and sell them from there.  Like Gary says, give everyone a "one-stop-shop" with everything.  These would roll out like hotcakes.  

Gary, I am not much of a programmer, but could XML be made to work with a SC-DAC?

[Fanny Pack]

XML is nothing more than an organized way of specifying data in text format.  For example, here is some XML to represent a laser frame:

<Frame index="0">
  <Coordinate index="0" X="0" Y="0" R="0" G="0" B="0"/>
  <Coordinate index="1" X="1" Y="1" R="255" G="255" B="255"/>
</Frame>

I just made that up but it is pretty easy to see that it is a frame with a single diagonal white segment.  There are many other ways to represent the same data and it is as easy to add more to it.  For example:

<Frame>
  <Description>SampleFrame</Description>
  <ColorShift R="0" G="1" B="-1"/>
  <Coords>
    <Coord>0,0,0</Coord>
    <Coord>0,0,16581375</Coord>
  </Coords>
<Frame>

Same as above but I changed the data format a little and added color shift info to it.



Or at a higher level.

<Frame>
   <Description>Lollipop</Description>
   <Circle cx="0" Cy="100" R="25" Color="red"/>
   <Line start="0" end="75" color="white"/>
</Frame>
 
I just defined a picture of a red lollipop with a white stick there.

A soundcard or any other DAC can't use any of this information as it is but software can easily read this directly into objects and those objects can have functions that return the information in useful form.  For example, in the last example, the Circle object's render function could convert the circle into a sequence of points that are in a circle.  The Line object could return another sequence of points that are in a straight line.  The Frame object would take those and use something like DrLavas optimization routines to put them together in an optimized way.  The result is a sequence of coordinates that could be fed directly into a USB DACs API or into a WAV file or an ILDA file.

Anyway, that's the idea.  I wouldn't necessarily implement it that way but that is an example of how the whole thing could be advanced to something that is more than just a bunch of points, colors, and offsets.

[BlinkenLights]

XML is a storage format, not a playing format.. in the end all data gets turned into some sort of wave data just before its converted to analog by the on board Digital Analog Converter

[Fanny Pack]

i agree. i have been saying that it needs to be an easy product for a while..

James wants people to learn what the hell they are doing, i say make it easy for them..

We will never agree on this because james is hard headed.. smart, but hard headed

That isn't my philosophy.  Computers were invented to make complex things easy.  It's up to the computer programmers to take the problems and create programs so that the end user can be stupid like on Star Trek and say "Computer, fix me some Earl Grey, hot!"  Why should Picard have to worry about how the tea is actually made?  He's got enough weird ass aliens to worry about.

[BlinkenLights]

Hyena:
He actually says..  "Tea, Earl Grey, Hot" otherwise i agree..

I think its time for someone to start the thread concerning the new file format so we can start doing something.. we are all in agreement about the XML structure.. so lets start there.

[meandean]

  As for audio DAC offset amp info, James has posted much on his site. Drlava and James teamed up to make a fine six channel amp kit last fall, based on a circuit I cooked up a few years back, and now he's making up an 8ch rev. 300Evil offers his own version that I saw at SELEM 08. Typical laser DACs seem to be limited to a 30k sample rate (at least the ones I've seen), if you want to add CD quality music to ch 7&8 (as LB & LW offer), you need 44.1k. Hi-end audio cards offer at least 96k; scanners can only move so fast, but color modulators are solid state and could benefit from the extra bandwidth, just as a TV set (with its fixed scan rate) benefits from DVD vs a worn VHS tape. LW has plenty of complex color generation options, as well as the ability to import a photographic image as a color plane- high sample rates can make a difference with the right material.

[James]

The hard part is developing an engine that can take those objects and manipulate them in intelligent ways and then finally render and optimized 2D vector sequence that can be handled by the scanner.


The thing that I don't like about your WAV file solution is that it seems like you are playing tetris with data by turning it this way and that way to make it all fit within the combines of a file type that was never designed to hold that data.

I hate to say this dude, but you describe a complex scenario in the first paragraph and then don't see that WAVE is the solution.

Have you ever made a LaserBoy animation into a wave and played it through a sound card DAC into an RGB rig?

Wave is NOT the ONLY solution! It is PART of the solution. We need to develop a compressed file (folder) that can contain a variety of different file types; wave, XML, MP3, ILD, whatever...

The comp / de-comp should be entirely up to the applications that read and write the "file format". After all, it will be ONE file. It may have any extension we want.

It should be based on common, open source technology like tar gzip or similar, such that a person could change the extension on the file and open it with common tools.

James. 

[James]

It is absolutely ridiculous to reinvent the concept of multi-channel, high resolution digital to analog signal generation!

In other words, get on board with the sound card DAC people!

The hardware will work itself out.

James. 

[James]

As a point of general information...

Wave is a predefined file format that was put out there by Microsoft. It is very well designed.

There are variations of the wave file format that are a bit more complicated to read, but the basic idea is a file with a header that contains all kinds of information about the data that follows it. In this header there are numbers to point right to where the data starts, so the header can be extended in size and descriptive capabilities.

The data that follows is NOTHING BUT the samples that get clocked out the DAC; arranged in ordered blocks of channels in the correct order in time.

LaserBoy makes use of the fact that it is possible to add any kind of information to the wave file header. There is a developing list of things that it stores (once per wave) about the data.

Since we know that we have 8-bit unsigned values for red, green and blue, we know that translating those numbers into 16-bit signed integers will leave the 7 lowest bits all zeros. So we know that we can use the LSB (least significant bit) as a Boolean flag anywhere in the data in any of the color channels. This is how end-of-frame and unique-frame marks are stored.

I just recently added code to LaserBoy to be able to directly manipulate the bit resolution of ALL of the signal channels.

This might not seem like a big deal, but it is! It means that now even X, Y or Z might contain LSB sub-code information!

Back to the point...  :

The VERY COOLEST THING about wave is that... if all is well in your universe... when you double click on it an app opens up and plays it!

And THAT has NOTHING to do with lasers!

James. 

[Fanny Pack]

Interestingly enough, I really don't agree with much of anything you said.  So, let's just agree to disagree and continue down our seperate paths.

In regards to your last point, there's nothing special about clicking on an icon and making an application do something.  Try clicking on a Spaghetti file sometime.  Spaghetti will start up and load the file for you.  Welcome to the world of Windows.

[James]

My exact point is that in any modern OS you "should" already have an application associated with the .wav extension and it "should" be able to play a 6 or 8 channel wave... with NO laser software for miles around!

Wecome to the world of generic computing.

James. 

[Fanny Pack]

Yea, that's great until they accidently play their Pearl Jam CD and it beats the heck out of their nice scanners.  Nice feature.