The Challenge: Home-Made Laser Show for Under $700

[ambassador]

Using a typical laser pointer as the light source, a cheap notebook PC, some off-the-shelf components, and some free software; it is possible to assemble the equipment capable of displaying via a laser beam any text-based message on a wall at a distance of 14 feet - all for less than $700.

That is the theory. That is also the design challange to the members of the Candle Power Forums.

Just to get things going, here are a couple of possible parts to initiate the parts list.

1. Red Laser Pointer - $24
http://www.atlasnova.com/RedLaserPointer635nm.htm

2. Cheap Notebook PC from Pawn Shop - $100

3. ...


Of course, I am interested in making this thing too! Further, the theory indicates that this equipment will be capable of projecting some simple vector-based graphics in addition to any text message.

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[allthatwhichis]

The key will be your scanners and DAC. You can get a DAC on eBay for fairly cheap, <$100, that will work for popelscan which is free. It's ghetto, but free. I'm using it at the moment. You then need a set of scanners. I think there is a 20k set for <$300... These prices are off the top of my head, I may be off a little. I'll post some links a little later when I can look for them. That red laser pointer isn't going to blank so you will have lines connecting each letter in your text. You could always build a driver for it though...

 

[ambassador]

If 'blanking' is what eliminates the lines that would otherwise connect the text, then we must have blanking for this challenge. So, if the referenced laser pointer cannot 'blank' then we must use a laser that can blank. Thank you allthatwhichis for setting this challenge on the right course with regard to the light source.

Also, your forthcoming links to parts will be most appreciated!

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[abeland1]

I doubt that you will find any laser pointer with a built in ability to blank. Both my 650's and 635's are undoubtedly using a current mirror circuit to regulate the current to the laser diodes to compensate for varying battery voltages. See the following. http://www.allaboutcircuits.com/vol_3/chpt_4/12.html
The modules on the red pointers should come out with much less trouble than the greenies. I am sure there is a plethora of electronic technical ability on the forum to find a way into this circuit to cut off the supply of current to the diode with a standard TTL input. Remember that the case of the module is positive. Let's have a little fun with this. Here's the deal. The first three members of the forum to volunteer for the project will receive two 650nm pointers, one to blow up, and another to end up with a working unit. Publish your results on the forum and allow the members to vote for the best solution. The winner will receive two 635nm pointers and 1 5mW atlasnova green with a nice big MCA. Let the game begin.

 

[stevetexas]

Abe - that is a generous and tempting offer. I'd love to take you up on it but am afraid I don't have the technical skill to make it worthwhile.

I think we should leave this up to the members who know a little more and have more technical skill

 

[Aseras]

I doubt that you will find any laser pointer with a built in ability to blank. Both my 650's and 635's are undoubtedly using a current mirror circuit to regulate the current to the laser diodes to compensate for varying battery voltages. See the following. http://www.allaboutcircuits.com/vol_3/chpt_4/12.html
The modules on the red pointers should come out with much less trouble than the greenies. I am sure there is a plethora of electronic technical ability on the forum to find a way into this circuit to cut off the supply of current to the diode with a standard TTL input. Remember that the case of the module is positive. Let's have a little fun with this. Here's the deal. The first three members of the forum to volunteer for the project will receive two 650nm pointers, one to blow up, and another to end up with a working unit. Publish your results on the forum and allow the members to vote for the best solution. The winner will receive two 635nm pointers and 1 5mW atlasnova green with a nice big MCA. Let the game begin.

afaik you just need to add the ttl to a pointer. you simply interrupt the circuit with a transistor when voltage is applied.

http://www.siliconfareast.com/ttl.htm

edit:

you might even be able to incorporate this to be added to a pointer using a circuit say inside of a disc you place in before the batteries. you might be able to do with with the ttl input voltage and a magnetic switch to basically open the circut before the batteries without modifing the pointer wiring at all.

 

[dr_lava]

Hey, this is a great thread! I do hope we are successful even at a lower price, especially if it's only 1 color, but this is a good start.

It's possible that an aixiz laser module http://mfgcn.com/_wsn/page2.html (although still without blanking) could be modified more easily than a pointer laser. In fact, I have an opened 635nm module sitting in front of me now that they sent me a bit ago as a sample.

Still, it's hard to turn down a free laser offer, I'm up for the abeland atlasnova challenge!

 

[abeland1]

Hey, this is a great thread! I do hope we are successful even at a lower price, especially if it's only 1 color, but this is a good start.

It's possible that an aixiz laser module http://mfgcn.com/_wsn/page2.html (although still without blanking) could be modified more easily than a pointer laser. In fact, I have an opened 635nm module sitting in front of me now that they sent me a bit ago as a sample.

Still, it's hard to turn down a free laser offer, I'm up for the abeland atlasnova challenge!

PM me your address and they will be on the way.

 

[sysadmn]

Dang, wish I had the time...
I suspect the 14 feet would be the hard part. It can be hard to paint the surface often enough to get a good solid line. Here's one that used an AVR microcontroller and 16 mirrors, but seems to have a throw of about 2 feet:
http://heim.ifi.uio.no/haakoh/avr/

Some links from when I researched this last year, courtesy De.licio.us:

If you think it's hard today, image what it was like in 2002:
http://web.media.mit.edu/~stefanm/TinyProjector/index.html

DIY Laser Show, including homemade scanners
http://elm-chan.org/works/vlp/report_e.html

 

[stevetexas]

Abe -- you rock -- this is what is great about the forums.

Please PM me about a laser. I haven't bought from you before but WILL buy now since you're such a great supporter. Looking for a reasonably hi-power green or red.

 

[ambassador]

Here are a couple of links which are very relevant to this challenge.

http://spt06.chez-alice.fr/00/scan1.htm

http://www.skyfirelasers.com/boomdog/byoshow2.php

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[allthatwhichis]

Well, I'm at work and can't access eBay, but I will toss out the other place I type a lot at that has TONS of information about this... You may even call it a cheat. Photonlexicon.com has only a few members but we ususaly only talk about laser shows, mainly ILDA compatable projectors but DMX and generic ones also. There's also a link to the 20K scanners I was speaking, but those are DMX controlled and may need a thing or two to work with a ILDA DAC. I don't "THINK" so but am not totally sure.

I'd have to ask the seller who is a member at PL. I'll do a thourough search when I get home around 5am EST tomorrow. :candle:

 

[ambassador]

As another CPF member suggested earlier in this topic, the $700 limit may be significantly greater than needed for this challenge. Look what $650 gets you - already made and delivered to your door.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110101895837&ru=http://search.ebay.com:80/110101895837_W0QQfromZR40QQfviZ1

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[allthatwhichis]

Well... that's a piece IMO... AND it's gonna cost $120 to ship it here. That's splittin hairs I know but it IS a challenge right? Gimme a few and I might be able to make it off eBay...

O and you need software, and probably a DAC, that ILDA port is probably only the connector for AFTER the DAC.

 

[allthatwhichis]

8 bit DAC kit $33
10mW TTL Greeny=$80
20k scanners/galvos w/dmx board=360.00
New link for popelscan download=Freeware

We'll need that 15v power supply for the DAC, but who knows how much that'll cost. I've ran around town for a damn 12volt and had to spend $15 at a radio shack 30 miles away... so we'll be generous and way $20 All that above is shipped... $493.00 If you can find a cheap 30 to 60mW red you can take this optic=$22.50 and get RGY text...

possibly for less than $700. I bet you could get a 40 to 50mW out of a CD burner... :lolsign:

 

[abeland1]

8 bit DAC kit $33
10mW TTL Greeny=$80
20k scanners/galvos w/dmx board=360.00
New link for popelscan download=Freeware

We'll need that 15v power supply for the DAC, but who knows how much that'll cost. I've ran around town for a damn 12volt and had to spend $15 at a radio shack 30 miles away... so we'll be generous and way $20 All that above is shipped... $493.00 If you can find a cheap 30 to 60mW red you can take this optic=$22.50 and get RGY text...

possibly for less than $700. I bet you could get a 40 to 50mW out of a CD burner... :lolsign:

For a power source for experimenters this could be interesting:
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

 

[ambassador]

allthatwhichis - The $650 roughly included shipping (the eBay device cost $550).

The point is that this challenge can most likely produce the goal for significantly less that $700. This assertion is especially likely given that generous folks like abeland1 are offering incentives to encourage those with the technical expertise to pursue the challenge.

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[allthatwhichis]

Sorry, I'm just a good eBayer...

Well, beyond missing the price there, I just thought your figure was without shipping.

Although I've got at least $2000 in my projector. I would call mine a "budget" model too or as I like to refer to it as ghettofabulous.

I don't have any electrical skills. I can build ya a computer, program a video game, but could get you one good solder out of a dozen tries.

I actually thought you had $700 and needed to get a projector for a party or something.

I guess the above that I made up could be a rough ceiling for everyone to try and beat. The one thing I didn't include was any type of table or box. At first I used a piece of wood, actually a shelf I took off my desk. I just recently got a piece of aluminum to mount it all on, but the wood worked.

 

[allthatwhichis]

For a power source for experimenters this could be interesting:
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

:bow: You're the man... I can't beleive I've never searched this. I have several of them lying around with no purpose for existing. Now they can be re... purposed..? abeland1, I have been wondering, why don't you sell plug in lasers? Meaning not handheld. We need a good, honest distributor in the US. I'm just curious.

 

[Aseras]

abeland1 i was checking out your site and noticed this http://www.atlasnova.com/RemoteSwitch.htm

something like this seems to be the easiest and least damaging way of adding a ttl circuit to a pointer... easy to undo to just replace the endcap.

Do your reds have a real driver in them or are they just simple current limiting, or nothing at all?

I'm up for the challenge too.