USB Audio DAC mod + LaserBoy Correction Amp

Here are some nice pictures of a hand made LaserBoy Correction Amp and one of those famouse USB sound cards.

GRIBYX = green, red, intensity, blue, Y, X !

Cable shield is grounded.

The twin lead is USB +5VDC and GND (white stripe).

In order to get the right levels out of this audio DAC, you need to display the provided software effects / mixer application and set it to 6 channels. Then you need to set the level of each channel. This goofy thing has a built in digital gain with automatic digital limiting (YUK! :eek:). It has NO EFFECT if you set the levels to just high enough but not too high!

http://hacylon.case.edu/laser/LaserB..._audio_dac.jpg

http://hacylon.case.edu/laser/LaserB...ection_amp.jpg

See the long, plain black box? That is a DC/DC converter that takes +5VDC and provides +/-9VDC for the op-amps. How cool is that?

BTW, the printed boards are done and a bunch of parts are on their way! We will have 25 kits available very soon. More after that! Those DC/DC buggers are made when ordered!

James. :)

Excellent! I've got the same sound card sitting on a shelf, just waiting to be modded. Looking forward to being able to run Laserboy on a real DAC. (Also looking forward to trying out Dr. Lava's sound card driver that emulates the Easylase USB DAC. Hoping to be able to play some of Zoof's creations on it!)

Let me know when the printed balance boards will be available!

Adam

Hey, will Dr. Lava's driver et someone use LDS on a sound card DAC?

That's my understanding, Aaron. I'm hoping to be able to use it with Mamba Black myself. (Yeah, I know that Mamba Black has a driver for the QM-2000. I've actually run it that way, but I prefer to run Showtime with the QM-2000...)

Adam

Quote:

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Originally Posted by buffo

(Yeah, I know that Mamba Black has a driver for the QM-2000. I've actually run it that way, but I prefer to run Showtime with the QM-2000...)

Adam

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Amen to that. I'd like to find a "cheap" way to be able to run both, ST and LDS, on separate scanners of course... ;)

This amp should work with just about any USB or PCI, Dolby 5.1 or 7.1 surround sound card. I have not tried one yet that didn't work! :D

You might have to look a bit farther than the obvious output decoupling caps on some boards.

In the good old days, I just looked in the Linux kernel to see what DAC chips were supported by Linux drivers and got cards with those chips.

The card you see on my website is one I got of a shipment of three that cost a total of $21 sent to my door. It's a C-Media 8738 chip.

Something to note about The LaserBoy Correction Amp: It is an inverter! So if your DAC is NOT an inverter you will end up with an inverted signal! That means that you need to send inverted wave to the DAC so that it can pass it to the LaserBoy amp to be inverted again. Does that make any sense at all? Some audio DACs are inverters, so you send positive (non-inverted) information to the DAC.

James. :)

Quote:

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Originally Posted by James Lehman

Something to note about The LaserBoy Correction Amp: It is an inverter! So if your DAC is NOT an inverter you will end up with an inverted signal! That means that you need to send inverted wave to the DAC so that it can pass it to the LaserBoy amp to be inverted again. Does that make any sense at all? Some audio DACs are inverters, so you send positive (non-inverted) information to the DAC.

James. :)

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That's OK since both the driver and your wav writer routines have options for inverting the data.

Excellent! Pretty soon, everyone will be thinking in waves! :D

James. :)

im back!

anyways, i have a lot of catching up to do, but i saw this and I am very excited!

I've been meaning to clean up my external electronics, and a printed board would be quite spiffy. I also told some one I would build them one, but this would be a lot easier!

Cool James! Will you be selling the kits with parts and the printed board? Any ideas at what the cost is going to be?

Barold

DrLava and I put it together. He's got the boards and I just ordered a bunch of parts. We don't have printed instructions yet, but you already know everything you need to know!

James. :)

Quote:

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Originally Posted by James Lehman

DrLava and I put it together. He's got the boards and I just ordered a bunch of parts. We don't have printed instructions yet, but you already know everything you need to know!

James. :)

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I'll take two!

I think, as long as the other guy still wants me to put one together for him. Those dc/dc converters look pretty cool! that way i dont have lead the power back from my scanners to power the op-amps. sweet!

Uh oh, im starting to spend money again :/

Barry

Here is a photo of the front side of the board. You can see, it will be a breeze to assemble, no SMT parts. For just the board, it's $17, the whole kit including header connectors is $40. The pots and dc/dc converter make up a bulk of the component cost!

http://hacylon.case.edu/laser/LaserB...ection_amp.jpg

very cool you guys!

When are you expecting the rest of the parts to come in for the kit?

Ooooooooooooo! I want one. I WANT ONE !!! :D

James. :)

Quote:

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Originally Posted by barold

When are you expecting the rest of the parts?

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I dunno' I hope by early next week. Pretty cool that drlava and I live < 50 miles apart!

BTW If you don't want to, you don't need to populate this whole board. You could easily make a four channel, or even an XY driver with no blanking at all.

Quote:

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Originally Posted by James Lehman

Ooooooooooooo! I want one. I WANT ONE !!! :D

James. :)



I dunno' I hope by early next week. Pretty cool that drlava and I live < 50 miles apart!

BTW If you don't want to you don't need to populate this whole board. You could easily make a four channel, or even an XY driver with no blanking at all.

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But wouldn't it be a hassle to only sell the parts for a certain number of channels as opposed to a full kit?

Quote:

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Originally Posted by barold

But wouldn't it be a hassle to only sell the parts for a certain number of channels as opposed to a full kit?

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Huh? No. I mean if you buy the board only! :D

The only weird part is the DC/DC and it turns out it's not so weird. But unless you buy a bunch of them, they are somewhat expensive.

TLO72, TLO82, LF353 will all drop into the IC sockets. I'm sure there are even more op-amps with the same pin-out.

James. :)

Quote:

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Originally Posted by drlava

For just the board, it's $17, the whole kit including header connectors is $40.

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Are you taking orders yet? How about a PayPal address.?. I want one! (Will take the full kit.)

Adam

OOOOOO when can we order???:D

Quote:

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Originally Posted by barold

I'll take two!

I think, as long as the other guy still wants me to put one together for him. Those dc/dc converters look pretty cool! that way i dont have lead the power back from my scanners to power the op-amps. sweet!

Uh oh, im starting to spend money again :/

Barry

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Yes Barry, Im still after one :D I've emailed you anyways

This is looking well good guys...

One question barry, Do you need to buy this kit + the soundcard ? and what will that push the price too ? email me and let me know

Cheers

This kit is only the LaserBoy Correction Amp. Sound card sold separately! :D

James. :)

Payment page is almost ready.. awaiting confirmation and possible changes from James! :)

I see a SELEM project in the making... :D

Quote:

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Originally Posted by drlava

Payment page is almost ready.. awaiting confirmation and possible changes from James! :)

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Yeah! And you're waiting on all the parts too! :D

Looks like we will have 15 kits to sell (out of the first batch of 25). I'm going to hang on to some to take to SELEM with me and I think drlava wants to play with our new toy as well. :D

Don't panic! I have already ordered more of the DC/DC things. Those have the lead time. All the rest of the parts come in about 2 days! :D

James. :)

The Purchase thread:
http://www.photonlexicon.com/forums/...5288#post55288
:)

hi, is there any way to avoid using that dc/dc converter? i cant find d106e anywhere... where can i buy one?

If you go with the original design, you would be using +/-12VDC from the computer power supply. But that requires that you have a desktop computer and you can get to the power supply! Alternately, you could use the +/-15VDC that powers your scanners. In either case, put some filter caps on the board near the power pins of the op-amps, accross each input voltage to ground.

http://www.akrobiz.com/laserboy/graphics/laser_m_95.jpg


James. :)

Weeeeeeeeeeeeeeeeeeeee!!!!

:D:D:D:D:D:D:D:D:D:D:D:D

http://hacylon.case.edu/laser/LaserB...pleted_kit.jpg

:D:D:D:D:D:D:D:D:D:D:D:D

http://hacylon.case.edu/laser/LaserB...ted_kit_01.jpg

:D:D:D:D:D:D:D:D:D:D:D:D

http://hacylon.case.edu/laser/LaserB...dio_dac_01.jpg

:D:D:D:D:D:D:D:D:D:D:D:D

http://hacylon.case.edu/laser/LaserB...dio_dac_02.jpg

:D:D:D:D:D:D:D:D:D:D:D:D

http://hacylon.case.edu/laser/LaserB...ection_amp.jpg

:D:D:D:D:D:D:D:D:D:D:D:D

http://hacylon.case.edu/laser/LaserBoy/tweak.jpg

:D:D:D:D:D:D:D:D:D:D:D:D

James. :)

Suuuuhhhhwweeeeeeeeet!

Does the kit come with a DB25 connector for ILDA ?

Quote:

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Originally Posted by seanharrison

Does the kit come with a DB25 connector for ILDA ?

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No. I just use an old PC style parallel header to port ribbon and hack off the header end.

James. :)

Wooo Hooo!

Lookie here!

I can hook it up any way I want to now! :D

I soldered in the pins on the output of this board, but I should have soldered in the sockets. Oh well. I just tacked the sockets on the bottom of the board, and went from there. This is what I ended up with. At least this way, I have a set of voltage test pins and output sockets! :D

http://hacylon.case.edu/laser/LaserB...ion_amp_01.jpg

http://hacylon.case.edu/laser/LaserB...ion_amp_02.jpg
Future expandable! Why do those gold pins look like fiber optics? Weird!


James. :)

When metal cables get cut nice and straight their ends are real shiney, the flash reflected off the ends and made that effect. :cool:

So what did that "kit" there cost to make, or would it cost? And if you happened to have a kit, what would it cost assembled?

Yeah, I'll make one for you!

The USB sound card is $25 from eBay. I just ordered another one, for no particular reason. (Probably the same fource that motivates "Dad" from those videos!)

The LaserBoy Correction Amp kit is $40. I have 5 unassembled kits right now. There are more for sale from drlava.

I also have a few more D25F connectors with attached ribbons.

How about a solid $70 for parts plus whatever you want to tip me for making it? :D

I don't really mind at all. I need some more practice and I like to make stuff.

That offer is for you only, because you asked me! I am not into the idea of making hundreds of these things for peanuts! :rolleyes:

Those metal ends are individual gold pins pulled from the plastic pin strips. Yes, they are quite shiny and they have flat surfaces.

James. :)

LaserBoy takes it both ways on the ins and the outs!

:eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek:
http://hacylon.case.edu/laser/LaserB...ted_kit_03.jpg

http://hacylon.case.edu/laser/LaserB...ted_kit_02.jpg
:eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek:

James. :)

Its all looking very impressive, I can wait to get mine :D

Quote:

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Originally Posted by James Lehman

LaserBoy takes it both ways on the ins and the outs!

:eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek:

:eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek::eek::eek::eek::eek::eek::eek::eek::eek: :eek::eek:

James. :)

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Eeewwww, so BAD!!! :p

Quote:

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Originally Posted by allthatwhichis

Eeewwww, so BAD!!! :p

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Yeah, I know. But I'm not the one who came up with "male or female" to describe electrical connections. I just went with it. :rolleyes:

James. :)

USB DAC settings in Windows for Media Player playback of LaserBoy generated waves!

http://hacylon.case.edu/laser/LaserB...C_settings.jpg

This is AFTER you have already set the standard Windows sound system mixer to max for both "Speaker" and "Wave". You can mute everything else.

Note, the +0, +2, +3 level settings. This is what it takes to make Media Player play the color channels loud enough for the correction amp to get them up to +5VDC. The X, and Y level settings are up to you and your likes. But, don't get crazy. This DAC has digital gain and digital limiting. If you set it right, it looks perfect!

NOTE: These settings seem to work for me with my O-scope and multi-meter. Your mileage may vary. :D

I arrived at my color channel settings like this: I maxed out the 50K gain pots and set the level in the USB sound card control to show just over 5 VDC on my meter, while I was playing circle.wav. Then, I backed off the 50K gain pot to set it to exactly +5.00 VDC. If you click right on the little + and - signs you can change the levels by 1 dB per click.

Let's see if I can piece together some emails to make sense of all of this.....

In the original drawing by Dean C. Hammonds, there are three separate pieces. In the new USB enabled design, two of these are irrelevant, but I will explain them anyway. The one that has the zener diode and the 1K resister is a -5.1 voltage reference. This is the -5.1 volts that gets mixed via the 10K trim pot into each channel to do the offset voltage correction. The more of the -5.1 volts you mix with the all positive signal, the closer it gets to being centered over zero volts. There is only need of one negative reference voltage. It is the same for all channels. In the new design we went with a negative 5 volt regulator (pretty much the same difference). The other thing in Dean's drawing is a set of caps that get put on the board, close to the chips power inputs. This is to filter off any noise that may be on the power supply. These are not necessary in the new USB design, because they have been replaced with a DC/DC converter and an appropriate compliment of 10uF tantalum capacitors. That leaves the op-amp circuit itself. This has not changed in any way. You need one of these for every channel. the input to this circuit is the other end of the wire you tacked onto the USB sound card; one per channel. The output of this circuit drives your scanners and your color mods. That's the {X, Y, R, G, B, I} stuff. Each signal is in its own channel.

http://www.akrobiz.com/laserboy/grap...laser_h_95.jpg

The LaserBoy Correction Amp is single ended. That means there is one-and-only-one ground and one signal lead for each channel. Your scanners are most likely balanced input. Which means that there is a ground, a positive signal input and a negative signal input. This is so you can run very long lines to the scanners and not pick up noise. It is a lot like an XLR professional audio connection. You don't need to worry about that. If you connect the ground from the LaserBoy amp to the ground of your scanner inputs, then also ground the negative inputs on your scanners, you send the LaserBoy X and Y signals to the positive X and Y inputs of the scanners. If you flip it and ground the positive inputs on the scanners and hook the LaserBoy outputs up to the negative scanner inputs, it will flip and mirror the image.

EDIT: This USB sound card is not an inverter, so in combination with The LaserBoy Correction Amp, the signals ARE inverted! See below as to how to compensate.

NOTE: It's fine if you only want to use one green laser. Just go along with the whole 6 channel thing. You only really need three of them. But this system, as it is described will work fine for you now and let you expand your options in the future.

When you play a 6 channel wave file into a sound card that can do 6 channels or more, you actually are using 6 DACs; one per channel. A DAC is a digital to analog converter. The ones that are on a sound card are made for sound! But that's OK. We just need to get around some of the limitations of that. A DAC takes a stream of numbers in the form of signed 16 bit integers and converts those numbers into proportional voltages. It is clocked. That is to say, it converts a number to a voltage at a rate of so-many samples per second. Since a 16 bit signed integer can be either negative or positive, so can the resulting voltage. BUT! There is one issue right here that I need to point out. There is no law that says that a positive number must always result in a positive voltage. With sound, absolute polarity doesn't really matter (or so they say). So let me tell you right now that some DACs invert and some do not! Not to worry. There is a cure for this! As a matter of fact, the LaserBoy Correction Amp is an analog inverter! That means if you feed a positive voltage into the input it will come out as a negative voltage. It sounds a lot more confusing the it really is. Just think of it like this: any number times negative one is just as far away from zero. It's just on the other side. All you need to do to get it back is multiply it by negative one again. Anyway... Back to the six channels. The analog side of a sound card is DC decoupled, so you have to eliminate the output decoupling caps and then you end up with an analog signal that is all positive voltage. So, you take each one of the six separate, all positive and somewhat puny signals from the USB card and put them right into each one of the numbered inputs on the LaserBoy Correction Amp. The LaserBoy Correction Amp does two things to the signal. It allows you to mix a negative voltage with the all positive signal to bring it down to center over the zero volt line and it gives the signal enough gain (multiplies the voltage) to properly drive your laser equipment.

So now we have the week all positive voltages coming from each channel of the USB sound card, going into each of the inputs of the LaserBoy Correction Amp.

Good!

Notice: We have not hooked up ANY laser stuff yet!!!

Now we need to set the trim pots. The first thing you want to do is set your gain to mid scale. You do this by turning the gain pots (50K) counter clockwise, until you hear or feel a little click. That means that you have run off the low end of the pot. (It's OK. They are made for this.) Now, did you get 25 turn pots? If you bought an official LaserBoy Correction Amp Kit you did! OK. Turn each gain pot from all the way out to mid scale by counting up to half the total turns. If you have 25 turn pots go to 12 full clockwise rotations. Once you have all of your gain pots set, you can set the offset pots.

Here is where you need a meter! With the USB sound card plugged into a computer that is on and has the drivers installed... you will be able to measure the idle state of the sound card. In other words, don't play any sounds. Just let it sit there, like it is supposed to be silent; but fully powered up and ready to go. Set your meter to DC volts (milivolts, if possible) and hook the black lead up to the LaserBoy Correction Amp ground. Now check the output of each channel of the LaserBoy Correction Amp. You are trying to get each output corrected to zero volts. You can check the corespongin input to the amp with the volt meter and see that it is about +2.25 or so volts DC. Now when you put the red meter lead on the output of each channel of the correction amp, you can set the offset pot (10K) to compensate. The more negative voltage you mix (clockwise) into the positive offset, the closer it will get to zero volts. You can go past zero into the negative, so adjust with care. Do each channel this way. Set them all to measure as close to zero volts as you can get (hold your breath!).

Now you are ready to set the gain pots. You know for sure what you need on your color channels (+5 VDC max). So lets do these first.

You need to make a wave in LaserBoy of the white circle.

EDIT: To make waves that will display correctly on an inverting system, hit 'u' from the main menu and toggle option 'd' to on (inverted wave output). Now when you save wave information it will be inverted. There is a tag in the header of the wave that indicates this inversion, so you and LaserBoy will know that it is inverted. If you need to make this wave non-inverted, hit 'b' (LaserBoy wave utilities) from the main menu. Then choose option '7' (invert polarity of LaserBoy wave) and type the name of the wave file [Enter]. Note: The effect of playing an inverted wave is the picture will be upside down and backwards and the color mod information will be useless! Color mod information is supposed to be all positive voltage and therefore would be all negitive.

First hit [Tab] to get to system settings and set the still frame duration in seconds (option 'a') to 300. That's 5 minutes of a still, white circle! Now [Esc] back to the main menu, arrow to frame 9, the circle, and hit 'o' (letter o) to output a file. Choose option '0' (zero) to make a 300 second wave of the current frame. Call it circle.

Now navigate to the LaserBoy\waves folder, find circle.wav and play it in Media Player.

You can get a good idea of how to set X and Y by measuring AC volts. You will have a sine wave in Y and a cosine wave in X. Those settings are relative to what size you want your scans to be. All the other channels should be set to +5.00 VDC. They are supposed to be driving analog color channels to full-on (white). When you stop playing circle.wav, these voltages should drop back to zero.

If anyone has any corrections or additions to this information, please feel free to join in!


James. :)

You are a hero! I can't wait to try this out, I hope my kit and soundcard gets here soon!

Thanks! :D


Please ask a lot of questions. I've worked with this stuff for way too long. I might assume I've already pointed some things out. :rolleyes:

James. :)

Got my kit in the mail yesterday. Hopefully I will have time to assemble it this weekend!

Adam

Awesome! Keep us posted. :D

James. :)

Using an oscilloscope, here are the best non-distorting settings I found to compensate for Windows Media Player 9 (on XP) per-channel gain changes. When playing wavs from Windows Media player only, other players may have no gain offsets. These gain changes are only necessary if you are playing LaserBoy Wavs. if you are using the EzAudDac driver, do not tweak the per channel gains, leave them all at 0. But remember to turn the wav gain all the way up in the mixer for both cases.

http://hacylon.case.edu/laser/LaserB...g_settings.jpg

Well, I didn't get a chance to work on the sound card *or* the correction amp. :( Spent the entire weekend working on my RGB projector.;)

Finally got the remote kill switch working. I completely re-vamped the interlock circuit and had to make more than a few wiring changes to get everything working the way I wanted it to. I can now use the kill switches on the remote box *or* on the face of the projector, and I can also re-start the projector from either the remote box or from the run switch on the projector.

I also made a "remote-box eliminator" dongle so I can run the projector in local mode without hooking up the box. Everything has been tested and it works as it should.

In addition to all that, I installed my replacement green laser (which entailed a complete re-alignment of the optics) and I also installed new scanners (which entailed a shitload of changes to the mounting system for the scanners *and* the shutter).

Whew! Nearly 18 hours worth of work! But it should be all set for SELEM. :) (Still need to install the table back in the projector and secure everything - should be able to do that tonight.)

Guess I'll have to wait on the sound card DAC though. :( I still need to get a few things done on the HGM5 argon (the one with the 903 tube in it)... Not sure if I'll get the exterior case finished, but at least I'll have it lasing in time for SELEM. (So it might not be pretty, but it *will* be putting out at least a watt of multiline loveliness!)

Adam

Bring the bits to SELEM. If you want, I bet I could find time to build it for you right there. Well... maybe not in the dark!

Building the kit and tapping into the USB sound card take less time than setting it up and tweaking the trim pots!

James. :)

James, I might take you up on that offer! ;) I'll bring the parts for sure.

MechEng3:

I've been working on the projector some more. Found the source of my noise problem last night. The combined PSU for the DPSS lasers has to go. (Tried to use that large 5V PSU I bought from you last year to run them both, but it's noisy as hell.) So it's back to the separate PSU's that I've had in there all along. Sigh. More re-wiring.

Good news is that the alignment is done and the table is hard-mounted again. Also, the new scanners are in and they work great! With the new green laser my power output has shifted a bit. Now I'm limited on red. (Funny - you'd think it would be blue...)

One more day and I'll be done with the RGB projector. Then I can start working on the argon! (I *will* have the HGM5 working for SELEM. It may not have covers on it, and might look ghetto as hell, but the damn thing will be lasing at over a watt, I promise!)

Oh yeah, and I've got a new beam show to share. ;) (Told ya I've been busy!) :D

Adam

buffo, I'll try to make a new kit that I have here (not mine that got a little smoked :rolleyes:) and I'll just trade you. Then I can do the USB mod part as a demo. OK?

James. :)

James:

DEAL! :D I've got the same sound card as you do anyway (the small, blue, 6-channel USB unit from E-bay).

In other news, I thought the PSU was the source of noise in my projector. It's not. :mad: Still working on it. (Got parts laying all over the island in the kitchen... Wife is not pleased!)

Adam

It's done. I just have to test it and tweak it. :D

I'll probably make another one just for kicks.

James. :)

Quote:

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Originally Posted by buffo

In other news, I thought the PSU was the source of noise in my projector. It's not. :mad: Still working on it. (Got parts laying all over the island in the kitchen... Wife is not pleased!)

Adam

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Adam... it is THURSDAY! Projectors should be all but PACKED! :rolleyes: