Topic: LaserBoy Projects Step-By-Step

[James]

Let's just skip about a bizzilion detales and get right into it!

Rotating Gears!

First we'll start with some of the stuff that is kinda' already waiting for you to demo!

If you open up LaserBoy as-is, it will automatically load a file called in.ild.

That file contains a number of demo frames.

You can flip through the frames with the left and right arrow keys.

You should see that the frames are numbered and they start with the number zero!

On the right side of the window, next to the vector display area there is a panel of information.

You should see the palette that the current frame is using, a target palette next to that and some text below the palettes.

The text is the name of the current frame palette (the target palette name is sideways up above).

You see 2D (or 3D) frame in yellow followed by the frame number.

In cyan, you see the number of vertices in the current frame.

Below that you see the number of segments in magenta.

A "segment" is a continuous string of lit vertices; the lit parts between the blanking.

If you right arrow and look at frames 1, 2 & 3, you should see some gears.

Here's the fun part...

Just because those frames are there LaserBoy knows how to find them. Each one of those frames can be scaled, moved and rotated to make a series of frames that become an animation!

When I say "The main menu", I am talking about the menu you see when you first start up the program. "Welcome to LaserBoy MM-DD-CCYY !!!!" is at the top.

From here, tap the 'o' key for output.

Choose option '5' ILDA generate and save frame set effect.

You should see a list of pre-loaded effects on the right side, where the palettes were.

Type "gears" without the quotes and hit enter.

Since LaserBoy is cross-platform-compatible, I would say that is case sensitive. File names are not, but that is only true for Microsoft. In Linux and Mac, EVERYTHING is case sensetive.

See it ? !!!

OK, when it is done, you have just made a brand new ILDA file called gears.ild. It is in the ild directory inside the LaserBoy folder.

In order to see it in LaserBoy, you need to open it.

From the main menu, tap 'i' for input.

Choose option '1' ILDA.

Type "gears" with no quotes at the prompt. Hit enter.

Choose option '1' to dump whatever is loaded in LaserBoy memory and replace it with the contents of gears.ild.

There it is!

To see it moving, tap the '`' key (one key to the left of the top row digit 1)

To make a wave of it that you can play from your modified sound card with a LaserBoy Correction Amp...

Tap any key to stop the animation.

Tap the 'o' key to output a file.

Choose option '9' to make a wave that is an animation of all of the frames that are currently loaded in LaserBoy memory.

At the prompt, call it "gears" with no quotes.

It will ask to please wait......

When it returns, there will be a new file in the wav directory inside the LaserBoy folder called gears.wav!

This wave file probably will not be quite ready to show on your projector.

You will probably need to apply sample offsets between the scanner signals and the color signals.

There are also quite a few settings that effect how this file was generated. We just assumed the default were used.

I will describe the various settings and what effect they have in coming posts.

Please ask questions or add detales as is needed!

James. 

[James]

Once you have a wave made in LaserBoy, there may be a couple of things you need to do to it before it will display properly through the sound card DAC to your projector.

The first major issue is the absolute polarity of the wave. As far as audio goes, most people agree that it doesn't really matter if your speakers are moving in-and-out or out-and-in. You hear the change of motion. As long as all of your channels are in the same phase relationship, you're fine.

But, with laser signals it matters! The most notable reason is that color modulation signals are supposed to be all positive voltage. So, if the signal is inverted, you end up with all negative voltage and the color modulation device that gets this signal can't do anything with it. It's pretty obvious something is wrong. Your lasers are not coming on at all! If you could turn on a laser and see what the scanners are doing with X and Y signals, you would see that the image they are scanning is both upside down and backwards.

A DAC is a Digital to Analog Converter. It takes (in this case) a 16-bit signed integer and converts that number into a representative voltage ~ from a stream of signed 16-bit integers, 48000 times per second.

Some DACs invert. Some do not. A positive number may result in a positive voltage from one DAC chip but a negative voltage from different kind of DAC chip.

It just so happens that the LaserBoy Correction Amp is an inverter! Even though it is TOTALLY an analog thing, it takes a signal on its input and the corresponding output signal is flipped upside down.

OK. Enough of that...

You need to invert the wave for it to show properly with the combination of the C-Media chipped USB DAC and the LaserBoy Correction Amp.

From the main menu, choose option 'b' wave utilities. Tap option '7'. Enter the name of the wave you want to invert. It should come back with a print out of the header information on the wave, indicating that it is either positive or negative signals.

Inverting a wave that has been inverted puts it right back where it started.

Another option is to tell LaserBoy to make all of its wave renderings inverted.

From the main menu, choose option 'u' user interface visuals and toggle settings.

Tap the 'e' key to either set or unset "inverted wave output".

[Esc] back to main. Choose option 'o' to output file information. Choose option 'i' to save the LaserBoy system settings file. The next time you open LaserBoy you won't have to set "inverted wave output".

James. 

[meandean]

  Gee Jimmy!

  It's about time you provided some documentation, but you do know that it is all in vain, as nobody wants to read the manual!!!

[James]

The other thing that you need to know about what to do with a wave to make it look right on your projector has to do with timing between the signals.

Scanning galvanometers are electro magnetic devices. They have mass! It takes some time to get them moving and to get them to stop. There is a measurable lag in time between the signal that gets sent to them and the corresponding motion that results.

Color modulation, on the other hand, is much quicker to respond. In some cases, it is instant; like with a PCAOM. In other cases, where the laser itself is modulated it can take time to respond. In either event, you can be sure that your scanners and your color modulation are not perfectly synchronized!

The effect of this is that the lasers come on before the scanners arrive at the spot where they are supposed to be. This has the appearance of tails or little line segments that hang off of the individual parts of the lit image. These tails are actually drawn before the rest of the line gets drawn. This often results in the line having a gap missing at the other end.

In LaserBoy, from the main menu, option 'b' takes you to wave utilities. First choose option '4' to set up your desired sample shifts.

If you have a PCAOM, you can take a guess that at 48000 samples per second, your scanners are about 7 samples behind your color modulation, so you can push your scanner signals ahead in time by 7 samples! For sample offsets on X & Y input the digit 7. You do not need to enter zeros for the rest of the list of offsets. You can just [Esc] out of this settings menu. Hit '4' again any time you want to see what your offset settings are and [Esc] to return to the wave utilities menu. If you have a direct modulated diode laser, you might want to try a sample shift of 5.

If you have a set of lasers that have different modulation reaction times, you can also compensate for differences between the colors!

Start out with an offset for X & Y of zero. Then, input negative numbers to indicate how many samples you want to delay each one of the color channels.

Once you set your desired sample shift list to a good guess, you have to apply it to the wave you made earlier. You do this with option '5' apply wave offsets. If you want to return a wave to a state of no offsets between the channels, then set your desired offsets list to all zeros. Since the offsets are stored in the header of the wave, LaserBoy know how to read it in whatever state it is in and rewrite it to any other state you want.

Once you figure out your offset settings and apply them to the wave, it should be ready to play!

James.