DIY Laser Pointer

Long days back, I'm here but in a different forum. I've postponed my uC projects for a few months. Now I'm in LASER experiments.

About 9 months ago I got a red laser diode from DVD-ROM. It worked nice but never looked like a 'real pointer like,' the beam is hard to find, the only thing you can see the collimated point o the wall. Even in darkness, the point was not bright enough.

I dont have any datasheet for this thing.
**broken link removed**

Now I decided to make a real pointer.
Firstly, I've consider the diode. I've only farnell.in to buy it. My local shop says a big no no for it.

A red one or a green one? I know green is better but will a red laser diode based pointer will be good enough? I'm a amateur astronomer, Can you tell, will a red pointer will be sufficient enough to point a star or constellation with its beam?

Now come to power of the diode. Farnell has two nice and low cost LD.
1:One has a power of 5mW and a maximum power of 7mW, they recommend it for laser pointer.
2:Another one has a power of 7mW and a max power of 10mW they recommend it for automobole DVD player.
So, which one to choose?

Will it serve my amateur astronomy purpose well?

Now this is specially for indian electrotechs(specially MVS Sarma), can somebody tell me a good indian store/shop/distributor who sell laser diodes? Silicon Components? They never replied my mail. Any store in india for that?

Hello theo92

Red pointers tend to have poor power and quality, that's why they are so cheap. Don't waste your money.

If you use CD-ROM lasers or buy a stand-alone red laser, you'll need a well designed power supply to get maximum efficiency without damaging the laser.

Don't play with CD-RW or printer lasers, they are infrared and are far more dangerous, because you can't even see the ray (maybe is reflected into your mom's dinnerware, and then straight into your eye)

For pointing the sky, use a green laser. This is what you need

Green Laser Pointer from Wicked Lasers.

I suggest you to wear appropiate eye protection, even the reflection of the laser will damage your eyes.

Green LaserShades
Red LaserShades

Don't use sunglasses, for god's sake!

_____________________

Now, if you are a real laser enthusiast, start from the beginning and the basics. (EDIT: don't get confused by the link caption, this site contains EVERYTHING, including how-to build various models. But yeah, read the safety instructions first, to avoid health and moral damage)

Sam's Laser FAQ - Preface, Introduction, What is a Laser?, Safety

If you study and experiment A LOT, and your mind is strong enough to overcome repeated failure and keep working, Who knows... someday you'll post your CO2 steel cutting laser on youtube

Thanks a lot.

I read the Sam's Laser FAQ before.
I know the theoretical portion of laser.

The laser that you see in the pic is a red one from DVD-ROM drive. It's not exactly powerful enough as I want.

I know the dangers of IR laser. I have one but I never powered it.
I cant buy from wicked laser(I love their green lasers n everything) as I dont have credit card stuffs. They're expensive somehow. That's not problem to me, I'll do it in a DIY way.

Do you agree that pointing the sky with a red laser of 5-10mW is impossible? Is it possible with a green ~532nm 5-10mW laser

The diodes which are available to me is :**broken link removed**
Will I buy this one :**broken link removed**

I get inspiration and have a dream to build a DIY laser like this one. This is from my(probably yours too) knowledge source wikipedia, the guy say "Description=A 5 mW 532 nm laser (class IIIb) directed at a palm tree approximately 30 m away. The laser was offset by about 10 cm to the camera's right. Both the camera and laser were mechanically steadied"

How beautiful is it, the green beam stucked the leave of the palm tree cutting through the darkness and fog. I'll build it someday, baby......
**broken link removed**

I'm a Laser enthusiast too! I would like to have my own copper bromide laser on a parking lot party, or make figures with motor-driven mirrors and a NdYAG
(No audience scanning!)

YouTube - Making a 3d homemade Laser projector

YouTube - BCM Planet Dance Laser Show

First, technical issues

I don't remember very well theo92, I've heard something about a "supra-radiant" property of some lasers; Along with atmospheric conditions (smoke, fog), it allows to see the beam crossing the air (or not).

(I know "supraradiant" is badly spelled, I hope somebody correct me)

I've never seen a red laser through the air, only reflected on a surface or drifracted through some materials... but seems to be easier with a powerful enough yellow or green one.

________

Now, economical-moral issues

Unfortunetly, it's a prohibitive science for the DIY, if you don't have commercial objectives on the project

I don't wanna dissapoint you, I suggest you to try an atmospheric TEA laser, is pulsed and mostly UV (and a little blue). When you got it working, you can jump to pure nitrogen laser, much more powerful UV (and a more blue) .
Get them working is enough fun and complexity for the average joe.

Now, if you are trying to build a green or yellow one, you'll need to get the chemicals that act as dyes, and somehow make or import the lenses. You have to deal with very high voltages and currents, toxic substances, and last but most important, import eye protection. You must have enough budget to replace defective parts, and rebuild the thing over and over again until it works.

I'm not saying this cannot be accomplished, In my case, I could get some of these parts here in Bogotá, the others from the U.S. BUT! What about the time and money? A home-made parking lot party doesn't even pay the AC cord of the unit

I don't know in your case, but I hope you get my point. Importing the green laser keychain is better, maybe the price is too high, but summing the costs of DIY developing, the dangers, and possible psicological damages of watching the thing failing over and over... makes sense. You can still show your DIY skills with the TEA

Hey Menticol, are those your videos by chance and or would you where to get those enclosed mirrors that it shows at the beginning. I have just made a little laser show of my own just consisting of one laser and tow mirrors on motors. But i would like to find better more stable mirror/motors?

Slickit said:

Hey Menticol, are those your videos by chance and or would you where to get those enclosed mirrors that it shows at the beginning. I have just made a little laser show of my own just consisting of one laser and tow mirrors on motors. But i would like to find better more stable mirror/motors?

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Haha no Slickit, just youtube videos I've favorited. What's your problem, alignement? A poorly aligned mirror will start to vibrate and then became airborne

With this method you can make perfectly round mirrors, and mark the exact central point (a very useful thing for you I guess)

My mirrors are round but since they are angled they start to vibrate pretty bad at high rpm's and in that video it looked like he had a very nice mirror in a metal case and it just looked very stable and reliable, not that mine arent but id like to stopo the vibrations.

Slickit said:

My mirrors are round but since they are angled they start to vibrate pretty bad at high rpm's and in that video it looked like he had a very nice mirror in a metal case and it just looked very stable and reliable, not that mine arent but id like to stopo the vibrations.

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Yes they may me round, but if not perfectly centred vibration will ocurr
Use the method I've shown

My laser diode at work.

I can see the focused point even at moderate light but cant see the beam even at 100% darkness. I didnt tried it at smoke.

theo92 said:

My laser diode at work.

I can see the focused point even at moderate light but cant see the beam even at 100% darkness. I didnt tried it at smoke.

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You can't see the beam unless it hits something, doesn't matter how dark it is. To make the beam visible you need dust, mist or smoke for it to travel through.

Nigel Goodwin said:

You can't see the beam unless it hits something, doesn't matter how dark it is. To make the beam visible you need dust, mist or smoke for it to travel through.

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oops!!it's a general properties of light. We cant see anything if light passes freely without a medium. Thats why mine not work. I'll try it with my father's cigarate smoke.

I AM rather confused with green laser modules. Does they simply use a green laser diode or a Nd:YAG IR laser diode, and then use a non-linear optical medium like Lithium triborate (LiB3O5) LBO crystal to convert base Nd:YAG lasing frequency 1064nm to green 532nm according to (my all time favourite) wikipedia.

Does the same applies to blue/violet one? I don't think so, as I some blue diodes at Laser Components company website. But I didnt saw any 532nm green one? Is the 532nm green laser diode not available?

I'll ask my chemistry teacher about Lithium triborate crystals, and will search in chemist shops for it, but I guess I can never find it here, it's so uncommon.

A 10mW red laser pointer will serve general needs. Will you agree?

theo92 said:

A 10mW red laser pointer will serve general needs. Will you agree?

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Negative. Red is not good for your application. Only green or yellow ae visible in that way.

A homemade Ndyag? Man, is like making an AMD processor in your basement
NdYAG is not like NaCl, I don't think you can just get them on the school lab. Don't forget the mounting and heatsink!

________________
PS: You are talking about a pumped laser, because IR light excites the dye, and it starts lasing.
________________

I've heard liquid dyes are great and powerful, but is very hard to get them lasing (high temperatures and other gasses required)

Sorry if I say things this way, but If you can't get a "simple" TEA Laser working, I can't imagine you working with the lenses and low tolerances required for advanced models. You may be get killed by the toxic substances or very high voltages of currents of a more complex laser.

Make a friend in the U.S., and get the green laser module or the keychain.

I was wondering.

What is the “blooming” effect of lasers and how long does it last?

I read what it sais on Wikipedia, but it is a little too genralised.

Could some one pleas clarify?

theo92 said:

Long days back, I'm here but in a different forum. I've postponed my uC projects for a few months. Now I'm in LASER experiments...................
Will it serve my amateur astronomy purpose well?
Now this is specially for indian electrotechs(specially MVS Sarma), can somebody tell me a good indian store/shop/distributor who sell laser diodes? Silicon Components? They never replied my mail. Any store in India for that?

Click to expand...

I saw your post rather late. I feel happy, the way you are into a new filed of your liking, Theo. I am not into the astronomy hobby. I have a general feeling that any energy would suffer attenuation. thus it might be impossible to be able to use mW laser devices to work for astronomy, if I get it right.

Incidentally, I have received my latest order from silicon components-10Nos of MCP6271. In fact they did not have stock, they got them for me. How ever, if they did not answer your mail, you may talk to them. BTW, I have no business relation with silicon components- No. I am also another like you.

Menticol said:

...and your mind is strong enough to overcome repeated failure and keep working...

Click to expand...

This is a very good point. I wrecked a laser module just uncrewing the lens while it was running. Lost another when I had it running off a wall-mount power supply during a thunderstorm. Finicky little things.

I have a green laser pointer for astronomy purposes. It was an item mfgd. by a company specifically for that purpose. It's impressive to see and even on a clear, starry night, it makes the job of indicating a specific point in the sky an easy job.

mvs sarma said:

I saw your post rather late. I feel happy, the way you are into a new filed of your liking, Theo. I am not into the astronomy hobby. I have a general feeling that any energy would suffer attenuation. thus it might be impossible to be able to use mW laser devices to work for astronomy, if I get it right.

Incidentally, I have received my latest order from silicon components-10Nos of MCP6271. In fact they did not have stock, they got them for me. How ever, if they did not answer your mail, you may talk to them. BTW, I have no business relation with silicon components- No. I am also another like you.

Click to expand...

MVS, I'm happy to see you back. I was interested in lasers when I first saw it in a book about 3-4 years, when a was a too-kid. Long days to go from then, when I first came to know about laser and it's facts and fancy and safety. Then I started experimenting with a DVD-ROM laser, it was cool, And I could throw it's dot upto 200 meters(if my guess is right), anyone can see it's dot pointed on a long palm tree from ground. The only thing, you can never see the beam, you can see it slightly if there's fog pr smoke.Now I've a DVD-RW diode extracted from my old LITE-ON 20x DVD writer. It's just terrible. As I dont have any safety goggles(I dont know where to get them, impossible to fnd in west bengal), I'm afraid of it, 250mW is more sufficient to kill the eyes. huh!! poor laser goggles I've packed it for later...
Astronomy is my favorite thing, and my passion.
As far as I know, even a 5-10mW green laser diode has the sufficient strength to point a specific star planet nebula or anything(which are visible of course). A red cant do it. There's a relation between 'visibility of colors to human eyes' with light wavelength that human eye is more responsive to shorter wavelength than higher ones. That's why a 532nm green laser can serves astronomical needs, while a same or even higher wattage 635-670nm red lasers cant do.
Now I'm quite moved from electronics for my exam. anyway now i'm working a little for a USB to MIDI converter with 18F2550, I'll built it from MIDI-nator, a great article in Nuts n Volts mag.Then a musical keyboard from JDP homepage
And for astronomy, I've a great dream for a bigggg ameature newtonian or dobsonian telescope. But here's no one to sell the mirrors. And finally a hacked webcam for astrophotography......i hope i can do while you're all on my side.
Thanks