Laser Gun Project

As part of my research at work, I was looking at laser diodes. They certainly have improved on these quite a bit lately. I was looking at 405nm BluRay burner diodes as a possible light source to locate brain tumors. Patients are given this stuff called ALA (5-Aminolevulinic acid) dye that selectively attaches to cancer cells, then 400nm light is used to excite the dye, which then glows red, making it visible to the surgeon. This way the surgeon can be sure to get it all out during surgery.

Anyway, in the process I ran across a bunch of more powerful diodes on eBay and decided to get one to play with.

I found a '70s era Weller soldering gun which I hollowed out and mounted the laser components into. Has sort of a '50s ray gun look.

Safety disclaimer: High powered lasers are very dangerous. Always wear proper protective glasses.



The diode module came with a lens and housing. The driver circuit is one of those cheap CC-CV simple switcher boards with adjustable current limiting. Laser diodes are like LEDs and need to run in constant current mode. The Weller gun came with a 2-stage trigger, so I modified the board for dual set points. The first stage on the trigger puts it into a low power aiming mode. This allows focusing and targeting at a relatively safe power (estimate around 50mW). Squeezing the trigger a little more, the second stage kicks in full power, which I have set at about 90% of the diode rating.

The lens has adjustable focusing. For close-up burn shots, you can focus closer and get much higher power density.

There is a key switch that locks out the power. I don't want my kids playing with this thing. I also don't want it going off in my pocket or backpack.

It runs off two 18650 Li-ion cells harvested from a used cardiac assist pump pack. The diode is running at about 1.5A, so I should be getting over an hour of burn time with these batteries. Below is a picture of the guts:


I measured the power output using a super-expensive power meter at work. I got around 1.6W. I might be able to push it to 2W, but I'd be risking blowing the diode. This is really impressive for a single diode of this size.

Here's a night shot going across my back yard:



The beam is really impressive in the dark. At closer range with the focus tight, it will burn wood instantly.

Here's a couple of YouTube videos: The first one starts out on low power, then switches to high power.

[youtube]wVFejhxKkcc[/youtube]
[youtube]qIv790sVubU[/youtube]


I've tried it out against various household insects. Ants are doomed. It's marginally effective against spiders. They can get out of the way fast enough to avoid cooking, but if I chase them long enough with the beam, I can eventually kill them. After a few of their legs get burned off, they slow down and are easier to hit. I have had zero success with anything that flies. I guess I need more power

Future possibilities would be to add some kind of beam stabilizer. Something like optical image stabilization used in cameras. The spot moves around quite a bit due to hand shake and spreads out the energy. If the spot could be stabilized, I could get a better burn. Some kind of optical sighting system would be useful as well. It's hard to aim before actually turning on the beam.

WOW that's amazing

Once you decide that you want a longer running time, put these babies inside:

https://www.akkuteile.de/lithium-ionen-akkus/18650/panasonic/sanyo-panasonic-ncr18650bf-3-6-3-7v-3350mah/a-100682/

Right out of Lost in Space. 8)

Too cool LOL!







(so this is what the kids with magnifying glasses grow up to be)

Nice build Fechter!! Lasers are so fun!

I always wondered what a real DIY kill-o-zap raygun would look like.

Not counting some cheapy laser pointer pen (and whatever is in the cdrom/cdrw drives), all I have here are the old HeNe tubes:

I have an old Nintendo optical gun I looked at for the conversion but it didn't have enough space inside for the batteries.
I also looked at some Star Trek phaser toys that would probably work. Best thing would be to CNC from scratch or possibly 3D print.

They have some 5W rated blue diodes out there, but too expensive for me. The 2W version was $60 with the lens and host. I can get an infrared 5W diode for under $100. I'd really like a CO2, but too expensive.
There are all kinds of these things on the laserpointer forum: http://laserpointerforums.com/

These things are small and light enough to place on a drone

Hand-held Class 4 lasers have been banned for sale in the United States starting January 1, 2015. Individual parts will still be available.

Next article in News of the weird: "Man accidentally kills cat with high-powered laser."

Glad to help.

Thanks gogo. I copied what you had and fixed my original post.

I want one!

I have the head off a Nd:YAG laser I was looking at before, but it would be pretty large and heavy as a hand-held. It might be workable in an air-cooled single pulse mode where you just discharge a big capacitor through the flash tube and let it take a while to charge up. This way the power supply could be much smaller. Each pulse would be about 1ms and dump several joules if things are efficient. Like a big camera flash.

Originally this YAG was operated continuously with water cooling. Output somewhere around 50W.

I also have a '60s era ruby rod that would probably fit in the same cavity. The ruby is less efficient but has a visible output. This ruby rod is from probably one of the very first lasers ever made. Back in the early '70s, I made a science fair project out of it. Fired it in a room full of people with no safety eyewear of any kind (though I was careful to aim it only at a dedicated target). It would give off a puff of smoke when hit by the beam. It would be in violation of dozens of safety regulations these days.



Inside it has a beautiful gold plated elliptical cavity reflector.

That would make an excellent Ghostbusters-Backpack-style unit; you could actually run it with it's water cooling in continous mode, until whatever batteries you use give out (unless you use a nice long extension cord. ) .

Or base it around any number of other scifi BMFG's. :lol:



Mmmm....or mount it on your bike, get those other pesky vehicles out from in front of you. (or ensure they don't run you over from behind!)

Hello,

I would like to make my first laser,

Are you able to post links to all the parts needed? :lol:

I don't care what color, But I would like something that burns stuff pretty well.
Ill print all the housing's, I do have a variety of safety glasses as well.

You might want to check out http://laserpointerforums.com/
Its a whole forum dedicated to these things.


I used parts from eBay.
The module is like this one:
http://www.ebay.com/itm/1-5-2W-445-...age_Lighting_Single_Units&hash=item27bc04fdc3

You need to mount this in a sizeable chunk of aluminum to provide a heat sink.

I used one of these as a driver:
http://www.ebay.com/itm/1PC-LM2596-...832?pt=LH_DefaultDomain_0&hash=item3f283b9038

I used 2 series 18650 laptop batteries for power. The rest of it is mostly just mechanical, putting the parts together.

okay thank you for that, I will buy those two items, Id like to make a laser butter cutter, if that doesn't work, Ill have a cool toy that iv always wanted.

Do I need to get a lens as well?

I will need to spend some time on that forum when i get a chance.

That laser module fechter linked has a lens (fine for low duty cycle), but you can get much better ones if going for high power, continuous use.
The same seller DTR has a website, he is a well respected seller on LPF. https://sites.google.com/site/dtrlpf/

Get the appropriate safety goggles and wear them EVERY time you cut the butter ... unless you make it into some sort of enclosed 2-axis CNC "Butter Cutter". Which would be cool.

The one I actually bought was this one:
http://www.ebay.com/itm/170644449122?_trksid=p2060778.m2749.l2649&ssPageName=STRK:MEBIDX:IT

1.5-2W 445nm Blue Diode in Module W/Leads & Aixiz Glass

They said this lens would deliver higher power but the beam is not as tight. I notice the spot is somewhat rectangular at a distance.

lol.. I love ebike and laser too..

that great to see Luke you and i in the same thread liking lasers!

I have sent a 980nm 150W laser diode head to luke for projects.. it buen metal

In my garage i actually have a GSI lumonic laser marker of 50W with a 808nm diode array. and a 30W CO2 laser

I have recovered those from my work that was sending that in trash... well that's what happen when you work in Optic technology 8)

I'll play with them once i finish my carbon fiber frame ebike project.

I remember back in 1993 when i built my first laser show projector with a copier He-Ne of 7mW and 3 tape dc motor with mirrors to do some lissajou frame.. I still have it today.

My last build is a 1.8W RGB full color laser projector. I also bought the great Quickshow software to draw some amazing light show animation graphic and athmospheric(beam)

Last year i have converted it to fully portable with some A123 cells. it can work for 3h. and i also installed a 160W rms class D amplifier inside for some music laser show presentation... anywhere!
http://www.photonlexicon.com/forums...n-160W-amplifier-and-120V-inverter-for-laptop

This week i'm working for fun on the great T E S L A logo laser animation. I will film that and send that to Elon... maybe if he like that he will give me a rebate on a P85D lol... what? everyone can have hopes !?

These days powerfull visible laser diode at low price are posible and hapenning witch is very nice!

we can get some 1W pure green 520nm, great royal Blue 462nm diode of 1.5W too ...

DTR laser is a great website to buy them.

Doc

okay guys,

I have ordered a 445nm laser, the one you suggested..

I wanted to know, what kind of duty cycle you can put it through?
are we talking like 10 seconds, 1 min? I plan on drilling a hole in a heat sink, Smearing heat paste and ramming it into the hole and hold it in with JB weld, Wont look pretty but I don't care.


All the sudden i find my self so interested in lasers now, I ripped apart a DVD rom writer drive i had laying around, I am feeding it 165mW, No lens.
I am trying to figure out a way to focus the beam, any idea's? I put the diode right upto a piece of black plastic and it made such a tiny burn mark, I can see if I was to focus the beam it would probably make some smoke perhaps.

It probably already does have a lens over it, spaced and designed for focusing inside the DVD surface.

You could try any glass lens (maybe plastic too?) and see what happens at different distances of lens vs laser and lens vs object, if you jsut want ot experiment.

If you want to actually know what you're doing (which I don't), there's a lens article on Wikipedia that has info and links on what curvatures do and how.

Yeah you're right, there is a lens already on it. " iv left the diode in the heatsink as well.. I might try remove it.
ill probably break it. but Ill try it because it will be easier to make a lens attachment from washers or something.


And i have already touched it so it's probably got oil all on it..
Today I grabbed a whole bunch of things to try and focus the beam..but it will be tricky to get a nice beam I think.. Ill just have to wait for this blue laser.



do you guys think a 9watt diode would be enough to cut pizza and butter? Even tho 2 watt is pretty insane for anything ill ever need.
I was interested in making a quick stupid youtube video.

I dunno how much power is needed for that...but maybe you could use the laser to engrave or modify things you've printed out in 3D plastic?

yeah ill test the laser on printed PLA and ABS, see what it does...Might be good to even clean up some parts with the hard to reach places.. not sure yet...
I sure would like to add a laser attachment to the printer and be able to cut out thin copper plates or even engrave stuff.


I am a little bit paranoid about using a laser in the sky, But I think it will be excellent to point out satellites and stars to my friends..

With enough heat sink and a small fan, the duty cycle can be continuous. On mine, the heat sink is a rather small aluminum piece, about 1" x 1" diameter and no fan. It gets warm after a couple of minutes.

I'll have to try butter and Styrofoam. I don't think pizza is going to cut nice even with 30W. It will just burn the surface and smell bad. One thing to keep in mind is some materials absorb the wavelength of the beam much better than others. Clear plastic will just pass the beam through and not do anything. Wood seems to absorb 445nm very well and fluoresces slightly. Something black, like electrical tape, absorbs almost all the energy so burns easily but smells very bad. You can pop a balloon from a good distance.

Reminds me of the old Saturday Night Live Jeopardy skit with a commercial for the Laser-Matic "And, what home would be complete without the amazing Laser-Matic; slices, dices and chops, everything from tomatoes to diamonds."