Kit to build a "toy" laser for a kid - any ideas?


My son is interested in, well, stuff that’s interesting. We talk about physics and astronomy, biology and evolution - all kinds of science stuff. He’s 9 years old and simply wants to learn.

Which brings me to lasers. I was explaining to him that LASER is an acronym (Light Amplification by Stimulated Emission of Radiation according to Wikipedia) which led a discussion of how lasers work.

Well, he would really like to build one. He designed one himself based on the concepts we discussed, but of course it is a 9-year-old’s design: “you feed light into it, and isolate a single frequency and then amplify it - see? A laser!” Ummm…

I would love to support his interest - is anyone aware of a kit where, you know, like 90% - all of the hard engineering - is done and you assemble the pieces and end up with a low-watt, harmful-to-no-one laser? It would be great if it was designed for education purposes where they discuss the history of lasers or describe what engineering had to go into the already-assembled pieces.

Any ideas? Thanks in advance!!

I collect books on how to build your own lasers. Most of these are probably beyond the scope of your son, and some don’t exist anymore, and some are dangerous.

Your best bet is a semiconductor diode laser. The laser itself already exists on a chip – you’re basically building the power supply for it. I’m sure someone must have packaged kits for these.

Building things like ruby lasers involve getting fairly expensive ruby rods. Scientific American’s Amateur Scientist had articles on building Nitrogen Lasers, Mercury Lasers, CO2 lasers and the like, but they all involve high voltage. Metrologic used to sell a do-it-yourself HeNe laser (complete withnpre-made tube), but I think that’s long gone now.

I’m wrong! Metrologic is still selling them!

And you might want to read this:

“Son, do you expect me to clean up this mess?”

“No, daddy, I expect you to die!”


Might he be interested in building, say, a laser level or laser pointer? Granted, you can buy the latter anywhere these days, but building your own is a good start.

To second CalMeacham, building your own laser from scratch is impractical and possibly dangerous, at least for a 9-year-old. I built my first CO2 laser at 16 with the help of a dangerously insane 47 year old man; it may have contributed (though I’m not certain) to my current eyesight problems. I would recommend staying away from build-your-own lasers, honestly.

But build your own laser TOOLS are a different story! My son is 7 and his favorite toy is a laser pointer he and I built. Radio Shack sells a laser unit; it still needs the rest of the circuit (power supply, voltage reduction, etc) to function, however. They also sell kit boxes, battery connectors, switches, etc. It’s a semiconductor laser and is, to all intents and purposes, safe. I don’t recommend shining it in yer eye, though. :slight_smile:

(Side note: my son’s first reaction after we got it working was, “Why isn’t it cutting through the wall, daddy?” Doh.)

At any rate, there’s lots of fun stuff to do with lasers even if you don’t build the laser itself. My son and I are currently working on a laser tripwire alarm system for his room (he saw a cat-burglar movie the other day and is obsessed with the idea now); I plan to make extensive use of the Radio Shack laser diodes.

Best of luck! Whatever you decide to do, encourage him! :slight_smile:

Dopers rule. Thanks you guys.

**CalMeacham **- you da’ best! Most of the stuff at the Metrologic website is way too expensive and tech for WordKid, regardless of how ambitious he is - but the laser pointer might be great! More importantly, that FAQ which starts with why NOT to build a laser from scratch is spot ON - perfect! I can hardly wait to review it with him!

**Sofaspud ** - are the RS lasers in kit form - i.e., all contained - or do they simply sell the semi-conductor laser and the other parts and you design the use and part together what you need based on that? If the latter, I am not capable of doing that as the lead parent™ so would like go with the kit **Cal **linked me to. If RS does have kits, I will check them out.

Thanks!! If anyone has any other ideas, keep 'em coming!

A little of both, actually. The RS lasers are small metallic cylinders that contain a lens, the driver circuit, the laser, and a resistor for safety (so you can’t blow it TOO easily by supplying too much juice). This is all wrapped up and unable to be monkeyed with in a sealed unit about the same diameter as a AAA battery, but about half the length. It’s got two leads coming out (red and black) for power. You supply the power (3v, or 2 AA’s worth, roughly) and it lases. How you supply the power and what the laser is for (beyond making a beam) is up to you. Laser pointer kit? All you need is a button, a box, and some batteries, for example (that’s what we used for my son’s kit).

RS has a laser level kit (or did, last time I went there) that uses this module plus other parts. I’m pretty sure they’ve got other stuff as well.

I don’t know how complex RS’s kits get, though. My son and I usually design our own things – well, he gets an idea he wants to build, I come up with a design for it (usually by searching the net), and then we get the parts and build it. He did some of the soldering for his pointer (not that it required much) and he’s only 7; I don’t think a 9 year old would find it hard at all, and it’s good experience.

If he likes electronics in general, might I suggest an experiment kit? RS sells these, I know (I hate sounding like I’m plugging Radio Shack, but it’s got good entry-level stuff); they consist of a board with various components on it, a bunch of wires, no-solder connections, and an instruction book that details how to wire up a bunch of different things. Oh, hell, here’s a link: kit

That one’s both more and less advanced that what I had as a kid, but it’s the same idea. I had loads of fun with mine. :slight_smile:

Edmund Scientific

At one of mt past lives, someone left on a very low-power laser (HeNe, I’m pretty sure). Its beam terminated in a wall. He’d gone to lunch or something, and it wasn’t worth turning off the laser.

So somebody else (NOT, I emphasize, me) came along and drilled a hole through the wall precisely where the laser hit it. He then stuck a match head in the wall and lit it. It left a beautiful soot-streak around the spot.

The guy who left the laser on came back, saw the hole apparently butrned through the wall, and freaked.

Of course, I’ve worked with laser that actually COULD blow holes in the wall. Sometimes ya gotta be careful. And there’s the time I melted a perfectly round hole in the stomache of my black polyester shirt. While I was wearing it…

Yeah… my experience with the CO2 laser was similar. As I’m sure you know, these beasties don’t lase in the visible spectrum. I did not know this (how I missed it is anyone’s guess, really, since EVERYTHING said “IR”, but I digress). I walked in front of it once while it was lasing… I thought it was off. That was an ouch time, and the shirt wasn’t even charred, dammit.

This is the same reason (“I thought it was off”) that makes me wonder if those days were responsible for my poor eyesight, which got rapidly worse in my late teenage years, but seems to have stabilized lately. Oh, and for a nice backscatter? Lase against a white wall. Doh.

The old coot helping me build it had a dismissive attitude about safety. As I said, he was crazy. He was a machinist who had been a high-voltage electrician (the guy they use to build power substations and such); he had lots of ‘leftover’ equipment and god knows what else he could lay his hands on. And he had nothing better to do all day long than fiddle with stuff, since he’d retired early and only worked occasionally as a consultant. He actually did most of the work… I was mostly the gopher and can-do assistant. :slight_smile:

Fun times. Not many folks I know can claim to have cooked their lunch on a laser! :smiley: