DIY LaserBoy Projector

I saved some scanners from the trash bin at work last friday so I decided to make a laser projector... I had been thinking about building one, and had been snooping around PL for a couple weeks. BTW, thank you all for the amount of information floating around this place!

I was very impatient over the weekend and found LaserBoy to be quite interesting. I emailed and talked to James, who was extremely helpful. Amazingly, I ended up finding everything I needed for this project at RadioShack and Circuit City. I ended up buying a Creative SoundBlaster Audigy, which was really easy to modify. It had large contacts where I needed to solder. You can see in the pictures below.

Without the breadboard and the wiring which I already had, the whole controller only set me back about $50. :)

http://i34.photobucket.com/albums/d1...8/P1010049.jpg
SUCCESS!!!!!! But, still waiting on a green laser with TTL coming in the mail.

http://i34.photobucket.com/albums/d1...8/P1010020.jpg

External electronics for setting commmand offset and gain, soon will be soldered to a board

http://i34.photobucket.com/albums/d1...8/P1010037.jpg
Sound card modication. I had to wire all 8 channels in order to figure out which one was which. I'm only running one laser for now, so all I needed was three channels. I also ened up powering the external electronics off the PCI +/-12V by soldering to a few pins on the sound card.

Barold

Very nice man! Much more that I could accomplish with an iron. ;)

That looks soooooooooo cooooooooooool !!! :D

Make sure you keep up with the latest (06_11_2008 v2) version of LaserBoy! I just fixed a bunch of stuff.

Please let me know if you find anything you think I should fix!

James. :)

That didn't take long! :) welcome and keep up the good work. Looks like you need a modulator driver now!

Quote:

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Originally Posted by drlava

That didn't take long! :) welcome and keep up the good work. Looks like you need a modulator driver now!

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Yeah, I am waiting on a green laser that is in the mail that supports TTL. The sound card and LaserBoy will provide the TTL signal for that when it gets here. :)

Barold

I've been playing with the settings in LaserBoy as well as the tuning on my scanners. Starting to look pretty crisp I must say!

http://i34.photobucket.com/albums/d1...8/P1010052.jpg

:)

Barold

My girlfriend, aka, the boss, refers to that sort of stuff as "smoking crack"...

That thing is drawing very well. http://www.photonlexicon.com/forums/...ons/icon14.gif Especially for the price tag. ;)

Now that's just down right pretty! :D

I can't explain how cool it is to (finally) see this stuff.

barold, I gotta' tell ya' from our text and voice exchanges, it seems like you went from noob to expert in about no-time-at-all. Nice work!

Thanks!

James. :)

I know you don't have colors or blanking yet, but can you see any difference between 96KHz and 48KHz sample rate (other than twice the wave file size)?

James. :)

Quote:

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Originally Posted by James Lehman

I know you don't have colors or blanking yet, but can you see any difference between 96KHz and 48KHz sample rate (other than twice the wave file size)?

James. :)

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The most noticeable thing is that the speed increases along with the sample rate.

I am under the impression I benefited from a higher sample rate and smaller vectors (lowered "longest optimized vector in points" down to 150 and maximum dwell down to 250 microseconds). My latest picture is at 96kHz.

But now that I go back to 48kHz and play with the settings (vectors 350, dwell 250), I really do not notice a bit of difference..... hmmm, i might go back to 48kHz, and benefit from the smaller wav files

You might find that even lower rates work well with certain images.

Keep this in mind:

It's really complicated.

Ha!

Things that are per sample will change with a different sample rate. Duh!

Other things that have to do with optimization will work the same at any rate.

I'm not quite sure I found all of the parameters needed to tweak data to a wave, but I got some stuff.

If you have RGB with analog modulation, then you can do 2D 24bit bitmap scans like this:

http://www.akrobiz.com/laserboy/graphics/laser_m_97.jpg

Then you will see every bit of the difference between 48 and 96KHz!

James. :)

PS My blue is so icky! I have mostly 488 (cyan) very little 476 or whatever... :( ... does everyone feel sorry for me?... anyway...
I am so looking forward to seeing nice bright SS RGB laser systems at SELEM! :D

have you tried laseroids with it yet? :)
use my driver (rename it to easylase.dll)

Quote:

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Originally Posted by drlava

have you tried laseroids with it yet? :)
use my driver (rename it to easylase.dll)

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I was going to ask you about that in your thread.... thank you! I'll post some pics when I get a chance to try it.

Barold

All the wave goodies are working as they should! You can now do proper sample shifting in the waves and still import them and show them on the display!

http://hacylon.case.edu/laser/LaserB...06_14_2008.zip

YEAH!

Let me know what you think.

One issue I know of is that you can set different offsets for X and Y and that really makes no sense and it doesn't apply. I guess I should just take one number for both X and Y together.

James. :)

Now I'd like to see some LaserBoy pictures in color with proper blanking and time alignment between the colors and the galvos.... please! :D

James. :)

Quote:

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Originally Posted by James Lehman

Now I'd like to see some LaserBoy pictures in color with proper blanking and time alignment between the colors and the galvos.... please! :D

James. :)

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I'm still waiting on my laser from axiz for TTL. And I dont think color will be coming for a while.

Barold

Update time! I got my laser from aixiz yesterday. A 50mw 532nm with TTL. I'm pretty happy with it... it works :)

Also, thanks to drlava's driver, I've gotten Laseroids, LaserTennis, and ZoofScope working. Soooo much fun. Thank you Zoof and drlava!

http://i34.photobucket.com/albums/d1...8/P1010056.jpg
Looks like it's time to get the new LaserBoy and try out that sample shifting...

Zoof's stuff:
http://i34.photobucket.com/albums/d1...8/P1010060.jpg
http://i34.photobucket.com/albums/d1...8/P1010063.jpg

:):):):):):):):):):):):):):):):):):):)

Barold

Nice! glad to see someone else using it. What speed did you have laseroids set on for the pic?

That pic was at 15000

I could probably use a little more tuning. There's a little bit of under-damped overshoot in there. I also have a little bit of noise in the system...

This pic is at 22000: (characters falls apart at 24000)
http://i34.photobucket.com/albums/d1...8/P1010067.jpg

barold, Have you compiled the latest version of LaserBoy for Mac OSX? Did I fix the hang-on-exit bug?

James. :)

Quote:

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Originally Posted by James Lehman

barold, Have you compiled the latest version of LaserBoy for Mac OSX? Did I fix the hang-on-exit bug?

James. :)

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It compiled, but still requires a force quit :/

I used 6_19_2008_v2

Oh! You just bummed me out. :(

Oh well. Do you get any specific reason why, that I might do a search on?

Thanks for doing the compile! :)

BTW How is the sample shifting working for you?

James. :)

I ended up bringing my laser projector to show my brother last weekend. I discovered it was an absolute pain to bring anywhere in its current state. First off, the power supply I am using is a +/-15 V 4.5A cinder block (accurate metaphor for both size and weight). Secondly, I had to take my desktop because of the PCI sound card. I also had to take my monitor because he just has a laptop.

So, I did a couple things to make the whole system a bunch smaller...

1. Laptop power supplies: I used two 15V 4A laptop power supplies to get my +/- 15V for both the scanners and external electronics. They can be found on ebay for about $15 shipped. I didn't notice much of a reduction in quality from the scanners.

2. USB Sound Card: It's all I wanted after I saw drlava's projector. I picked up the same one he had on ebay for $25 shipped. Now I can use my laptop!

Here's a pic of the sound card all hooked up:
http://i34.photobucket.com/albums/d1...P1010072-1.jpg
RGB moduation signals are strapped off to the side, just in case I need them later :D

Barold

Quote:

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Originally Posted by barold

I used two 15V 4A laptop power supplies to get my +/- 15V for both the scanners and external electronics.

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So do you have a real, like "third prong" ground anywhere?

James. :)

the laptop power supplies have third prongs, but I wonder if what you are asking has to do with this...

If I try to charge my laptop, my scanners shut off. I can see one of the 2 laptop power supplies I use for +/-15V shut off. I am probably doing something fundamentally stupid, but it goes something like this, and I'm not really sure how I would change it...

The +/- 15V supply "ground" connects to my scanners and my external electronics. The external electronics ground connects to the sound card ground so that I actually get readings from the DAC outputs. The sound card ground comes from the usb ground, which I assume connects to the ground to my laptop. When my laptop gets grounded through the charger, a problem flys all the way back to the +/-15V supply and shuts it off. :/

Barold

If you are using 2 plug-in line-lumps together as a differential PS, then you must be connecting the positive of one to the negative of the other; thus making a "new" ground and using the remaining wires as +/- voltage. Right?

Is there continuity from the ground shield of the DC output to the ground on the plug?

I don't think so.

So what is that third prong for anyway? ;)

Hint: Ground Fault Protect, 3 prong outlets are code just about everywhere in the US. So even if you only use the two spades and leave the third prong hangin', the plug still only goes in one way. This shouldn't really matter too much for low current step down transformers encapsulated in plastic lumps, but there are issues to be aware of; like where is the real DC path to Earth? !!! :confused:

Ah! And even worse, If I turn-on this brand-new expensive thing, will it become "The-New-Path" to ... POP, FIZZLE, SMOKE ??? :eek:

I have personally seen some really awful things that happened when someone thought "Hey! Ground is ground! Right?"
(I'm not gonna' say who. :rolleyes:)

Meter, Meter, Meter, Meter... ;) ... and then Meter and Meter again! :D

James. :)

Quote:

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Originally Posted by James Lehman

Is there continuity from the ground shield of the DC output to the ground on the plug?

I don't think so.

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Right, there is not continuity there on the +/-15V supply. There is only the two 0V and 15V wires

My laptop charger does feed an actual earth ground (from DC plug to thrid prong) as well as 0V and 16V. The earth ground is definitely tied to the chasis of the computer, which is attached to the usb chasis, which is the sound card ground, which eventually hits the 0VDC on the +/-15 V (thus tying one of the +15 to earth, which is probably why it shuts off). Does that sound like the problem?


Barold

Quote:

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Originally Posted by barold

Does that sound like the problem?

Barold

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I think you've got something there!

James. :)

Apparently it was just windoze automatically installing the wrong driver. I've got everything hooked up (and charging) now and it seems to be fine. Weird...

Barold;

Your power supply wiring is fine. If you need a +/- power supply for your scanners, there's nothing wrong with connecting a pair of DC power supplies in series and then calling the center terminal (where the + lead from one PSU meets the negative lead of the other) ground. So long as the outputs of each power supply are completely isolated from earth ground, you can create a new ground point in the DC circuit.

Furthermore, there's no problem bonding that point back to earth ground either. This is *exactly* how I have my scanners powered in my projector. I have a pair of 24 volt power supplies that are connected in series with ground defined in the middle. So long as the circuit is isolated, ground is whatever you decide to call it. (If I had tied the positive end to ground, I would have a negative 48 volt power supply, and if I tied the negative end to ground, I would have a positive 48 volt power supply.)

James;

That third plug on the wall wart is not a "ground fault" plug. The ground plug is simply there to allow a low-resistance return path for current so if the hot wire in an AC appliance touches the case, the current will (hopefully) flow back via the ground prong. (The ground wire is tied into the neutral wire in the breaker panel.) This should draw enough current to trip the circuit breaker before someone gets a shock from touching the case. And if it doesn't trip the breaker, at least it's a low-resistance path that will compete favorably with the (relatively) higher resistance of the human body in the case when someone *is* touching the case and the power is still on - hopefully (but not assuredly) preventing an electrocution.

Ground fault protection, on the other hand, requires extra hardware (normally installed on the circuit breaker or the outlet, but on some high-current-draw devices it can be included in the plug) that senses the current flowing through the both the hot and neutral wires in an AC circuit, and if it detects even a minute difference between the two currents it opens a circuit breaker. It consists of a sensing transformer, a comparator, and a circuit breaker. These devices can sense a difference of a few milliamps between the hot and neutral wires, and they are *very* fast acting. In theory they'll stop the flow of current before any dangerous shock occurs, though you will probably still feel pain for a brief instant.

Adam

I know what a GFP outlet is! My point was that if you do any new house wiring today, that IS up-to-code, you have to use them, at least in places like the bathroom!

My other point was that there are a lot of AC cords on things that have the third prong and don't use it. This is a strong indication that it should only be plugged into an outlet with all three holes present and that it will only go in one way. Of course there is also the fact that sometimes one of the two spades is wider than the other. This has the same effect.

Most home stereo equipment is only two prongs.

My Fender Twin Reverb, all-tube guitar amp has three prongs and a switch to choose which way to ground the chassis. So do other guitar amps. Yes, I have gotten zapped from touching the bass player!

James. :)

Quote:

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Originally Posted by James Lehman

I know what a GFP outlet is! My point was that if you do any new house wiring today, that IS up-to-code, you have to use them, at least in places like the bathroom!

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GFI protection for outlets within 6 ft of a water source have been required by the US residential wiring code for the last 20 years. They're not new by any means. (And yes, I have done both residential and commercial wiring.) More to the point, GFI protection is irrelevant to Barold's PSU setup.

Quote:

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My other point was that there are a lot of AC cords on things that have the third prong and don't use it. This is a strong indication that it should only be plugged into an outlet with all three holes present and that it will only go in one way. Of course there is also the fact that sometimes one of the two spades is wider than the other. This has the same effect.

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No, it doesn't have the same effect. One spade is wider than the other because it prevents you from swapping the hot and neutral. This is a different standard that is completely separate from the GFI requirements. If you swap the hot and neutral, you can *still* get shocked by a faulty appliance if you don't have the GFI outlet. On the other hand, even if the hot and neutral are reversed, the GFI will still protect you because it senses the *difference* between the two currents.

As for the ground prong; just because it's included on a lot of devices doesn't mean that it it's a "strong indication" that it should only be plugged into a grounded outlet. There are a number of devices that gain little if any benefit from the ground prong. A wall-wart transformer with an isolated secondary and an all-plastic case is an excellent example. What is that ground plug protecting you from? Where is it connected inside the device? There are no metal parts on the case that you can physically touch, so you *can't* get shocked. Furthermore, there is no connection from ground to the DC output. The ground prong is useless in that application.

So why do they have the prong? Standardization, mostly. And the fact that a third prong helps to hold the thing steady in the outlet. Also, to be in compliance with the electrical safety standards for appliances, you either have to include a ground plug *or* you have to double-insulate the internals. In most cases adding the ground prong is easier and cheaper. (Even if it's not actually protecting you from anything.) Bottom line: There are a large number of completely enclosed, all plastic devices that include the ground prong on the power cord even though it's not really needed.

Quote:

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Most home stereo equipment is only two prongs.

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Yes, for a completely separate reason: elimination of ground loops. You'll notice that most home stereo equipment has a metal chassis. Thus there is a significant risk that you could be shocked when touching the case if a hot wire happened to work loose and came in contact with the case. Yet there's no ground plug...

It's a textbook example of a situation where a ground plug would be ideal. But the risk of creating a ground loop (and the annoying 60 cycle hum that comes with it) is too great, so most stereo manufacturers decide to double-insulate instead. Slightly more work, yes, but it ensures that you won't have any hum...

Quote:

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My Fender Twin Reverb, all-tube guitar amp has three prongs and a switch to choose which way to ground the chassis. So do other guitar amps. Yes, I have gotten zapped from touching the bass player!

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If you got shocked touching the base player, and it wasn't a static shock, then something is *seriously* wrong with either the wiring in your amp or in his. Even if both cases (or even just one) were ungrounded, there shouldn't have been any way for current to flow between them unless you had a wiring fault that made one of the cases hot.

Was it a low-voltage tingle, or a "holy shit!" 110 V shock? If it was low voltage it's not nearly so bad and could have been caused be a number of things (maybe induced voltage in your case from the filament transformer), but if it was a big shock then you've got 110 volts on the case of your amp (or his), and that's *very* bad.

Adam

Quote:

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Originally Posted by buffo

If you got shocked touching the base player...
Was it a low-voltage tingle, or a "holy shit!" 110 V shock?
Adam

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It was of the "holy shit!" variety. It was in the basement of a house I used to own that was built in 1904. There was a very interesting mix of styles of electrical house wiring; some tube and knob, 2 wire and some three wire Romax. I think _that_ is exactly why that switch for chassis ground is there!

I think we agree on everything here. I'm just going from personal observation and you're going from training and experience. I don't think anything I wrote is so wrong that it's dangerous. Read it again. I pose more questions, really.

James. :)

Quote:

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Originally Posted by James Lehman

It was of the "holy shit!" variety. It was in the basement of a house I used to own that was built in 1904. There was a very interesting mix of styles of electrical house wiring; some tube and knob, 2 wire and some three wire Romax. I think _that_ is exactly why that switch for chassis ground is there!

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Ahhh... Starting to make more sense now. My guess is that one of the outlets in that house was wired backwards (hot and neutral reversed). It's conceivable that the neutral wire was connected to the chassis ground, and if one outlet was wired backwards, that would make the chassis hot. Pity you can't go back there with an outlet tester and check the wiring. Would be a good thing for the current residents to know about.

Quote:

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I think we agree on everything here. I'm just going from personal observation and you're going from training and experience. I don't think anything I wrote is so wrong that it's dangerous.

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I'm not trying to bust your balls. Just fleshing out the post with more info. If I sound like I'm being an ass, I apologize. :o It's been a busy week (20 hrs OT, and lots of nightshift too) and my "stop being a pedantic dickhead when you post" filter probably isn't working as well as it should. :rolleyes: I get that way sometimes... Sorry!

Adam

Quote:

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Originally Posted by buffo

"stop being a pedantic dickhead when you post" filter probably isn't working as well as it should. :rolleyes: I get that way sometimes... Sorry!

Adam

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Oh Man! You and me both! I thought I was the only "know-it-all" here on the PL. :rolleyes: I rely on the fact that others will correct me if I am totally off and in the danger zone. That's the beautiful thing about a public forum like this.

No offense taken. I appriciate the information fill-in.

Take care. James. :)

Thanks for all the grounding information from both of you. I'm glad to know that I am not doing anything stupid :)

Turns out my external electronics were mostly the problem, they were getting a little unhappy from being thrown around. There were a couple loose connections and my zener diode died. I fixed it up and put it into a project box for safe keeping. That also made the whole thing look a lot nicer, and more portable. My projector and everything I need to control it now fit in my backpack! :)

Barold

Hey Barold;

Any chance of you making the trip to SELEM this summer? I know it would be a long trip (14 hours or so), but you'd be able to show us your home-built projector and also meet the guy (James) that wrote the software you're using! Plus it's going to be a *great* weekend. Plenty of lasers, lots of geeks, and one hell of a dinner party Friday evening to kick it all off.

Give it some thought anyway... Sure would be cool to see you there.

Adam

Yea, you have already made your projector portable. :D All the hard work is over... except the drive. :rolleyes:

I would really like to head to SELEM. I might be able to make it. I've got friends in DC that I could visit to split the drive in half. We'll see, at this point I really cant commit to it :/

Barold

Just as soon as I get my current "job" project is out of the way, I want to really dig into LaserBoy and not come out till it's all working!

It's going to take some time. I need to get my old pure Linux system going again to be able to generate correctly shifted waves.

I will also be doing some REAL LASER testing this time. :rolleyes:

And I want to get drlava's stuff going and see Laseroids! :D

James. :)

Oh mannnn, I would have to drive through VA. Radar detectors are illegal and you get a reckless driving ticket for going 20 over. So much for cutting down on travel time...

You crazy kids think it's OK to drive more than 20 over!

I plan on driving about 15 under in the passing lane with my left turn signal on the whole way.

James. :)

Quote:

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Originally Posted by James Lehman

You crazy kids think it's OK to drive more than 20 over!

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Part of me questions the legality of speed limits... ;)

Quote:

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Originally Posted by allthatwhichis

Part of me questions the legality of speed limits... ;)

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Do the cops question that part of you much? :)

Just set the cruise control at 79, turn up the I-pod, and make sure you've got plenty of snacks and drinks in the car. Stop only for gas and to take a piss. The trip is over before you know it!

(How do you think I keep my sanity making all those solo-trips to Florida? Same way as above.)

Adam

not only 20 over, but anything over 80. a criminal offense! I just find that a little ridiculous.

I dont want to give the impression that I'm going to try and barrel down at 110mph, but I do like to keep it around 80. I wouldn't go a hair past 74 driving through VA.