This is about building a Class II <1mW Helium-Neon (HeNe) laser. It's also about a dream that's been a long time coming. A little back story would help.
As a kid, back in the 80s and 90s, I used to get Elenco electronic kits from my Dad and Mom as presents. I had them all, the Digital Roulette (K-25), the Space War Gun (K-10), the Pocket Game Dice (K-28) and many more. Even a few robot kits. Then I discovered lasers and all I could talk about for months was getting the brand new Class II Laser Kit (LK-1).
Of course lasers are dangerous and so both my parents said no, responsibly. I continued to pester them and a deal was struck: I write a report on lasers, about their history and safety, and they would buy it for me. So I went to the library, studied up on lasers, wrote the report, and in 1992 I got it. I was so happy I couldn't believe it.
Well, as chance would have it, I lost the instructions and we put off building the kit for a while. Then the whole thing got forgotten and packed away, lost to me for about 15 years. I found it about 5 years ago while I was moving and surprisingly everything was in mint condition. The instructions were still lost and so I checked the internet every year seeing if the schematics would pop up but they never did.
You see the board has no markings and I didn't have a full parts list, only the parts in the box. So the best I could do would be to reverse engineer the circuit, something I'm not great at. A picture would have helped tremendously but I couldn't even find one of those. Finally I tried looking at the Way Back Machine for even the smallest clue but only found this:
http://web.archive.org/web/19970125020504/http://www.elenco.com/dlxkits.htm#lk1
With all hope lost I finally decided to write Elenco for help, hoping that they had the 20 year old plans in their archive. I probably should have tried that first but it never occurred to me. Well wouldn't you know they sent me a PDF of the schematics and instructions the very next day! Suddenly I became a 12 year old again, giddy with excitement. So here I am ready to make a 20 year old dream come true and build that laser kit I begged for as a kid.
So if you're ready then come watch me build this old kit and bring my laser to life!
As a kid, back in the 80s and 90s, I used to get Elenco electronic kits from my Dad and Mom as presents. I had them all, the Digital Roulette (K-25), the Space War Gun (K-10), the Pocket Game Dice (K-28) and many more. Even a few robot kits. Then I discovered lasers and all I could talk about for months was getting the brand new Class II Laser Kit (LK-1).
Of course lasers are dangerous and so both my parents said no, responsibly. I continued to pester them and a deal was struck: I write a report on lasers, about their history and safety, and they would buy it for me. So I went to the library, studied up on lasers, wrote the report, and in 1992 I got it. I was so happy I couldn't believe it.
Well, as chance would have it, I lost the instructions and we put off building the kit for a while. Then the whole thing got forgotten and packed away, lost to me for about 15 years. I found it about 5 years ago while I was moving and surprisingly everything was in mint condition. The instructions were still lost and so I checked the internet every year seeing if the schematics would pop up but they never did.
You see the board has no markings and I didn't have a full parts list, only the parts in the box. So the best I could do would be to reverse engineer the circuit, something I'm not great at. A picture would have helped tremendously but I couldn't even find one of those. Finally I tried looking at the Way Back Machine for even the smallest clue but only found this:
http://web.archive.org/web/19970125020504/http://www.elenco.com/dlxkits.htm#lk1
With all hope lost I finally decided to write Elenco for help, hoping that they had the 20 year old plans in their archive. I probably should have tried that first but it never occurred to me. Well wouldn't you know they sent me a PDF of the schematics and instructions the very next day! Suddenly I became a 12 year old again, giddy with excitement. So here I am ready to make a 20 year old dream come true and build that laser kit I begged for as a kid.
So if you're ready then come watch me build this old kit and bring my laser to life!
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Signing UpStep 1: Safety, Tools and More!
This is the step where I tell you to be safe. Lasers are dangerous and if you aren't aware they can cause damage to your vision if used improperly. So please don't look at the laser. You've been warned.
Second, the power supply can be dangerous if you use it without the laser connected. Make sure you are careful with the power, you may get hurt. Or shocked. Anyway, pay attention.
If you're going to make one of these you'll need these tools to begin:
Attached are the original instructions and a scan of the educational pamphlet I filled out as a kid. Even though Elenco discontinued this kit in the late 90s I still want to point out that this is their kit and their material. I've included it here in good faith and as documentation for others that may find their own kit hiding after 20 years and want to build it:) Don't be a jerk and try to pass it off as your own stuff. That's my disclaimer.
Second, the power supply can be dangerous if you use it without the laser connected. Make sure you are careful with the power, you may get hurt. Or shocked. Anyway, pay attention.
If you're going to make one of these you'll need these tools to begin:
- Soldering Iron
- Solder
- Damp Sponge
- Safety glasses
- Needle nose pliers
- Wire Cutters
Attached are the original instructions and a scan of the educational pamphlet I filled out as a kid. Even though Elenco discontinued this kit in the late 90s I still want to point out that this is their kit and their material. I've included it here in good faith and as documentation for others that may find their own kit hiding after 20 years and want to build it:) Don't be a jerk and try to pass it off as your own stuff. That's my disclaimer.
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i cant seem to find the right ones and none of the shematics show any markings.
Thanks so much for posting this!
I tinkered with my first HeNe laser tube as a teen in the late 1970's. I still have that tube (it's one like yours but housed in a nice aluminum tube) and another larger one that is 2 feet long.
Thanks for sharing!
Every month I looked forward to receiving Popular Electronics, Radio Electronics, the Edmund Scientific, and other electronics catalogs every month!
I have been thinking about a revised compact power supply design using a TV fly-back transformer. Thanks to flat-screen technology, there is a glut of surplus CRT fly-back transformers out there for cheap.
My old power supply was simply a small transformer (120 VAC primary/900VAC secondary) coupled to a half-wave voltage multiplier (like the network of diodes and 0.01µF capacitors on yours) to get the open-circuit output voltage up to the several kV needed to start the tube, and a current limit resistor.
Hang on to way you have and enjoy.
Outstanding project and one I remember from my own youth. Great piece of work and thanks for the memories!!!
Thanks for the reply!
I used little standards to mount the mirrors in casting sand from metal shop.
When the thing was turned on I was blown away when it worked and so were the teachers. Their Laser came from Edmond Scientific.
We spent the next week playing with the focus and measuring beam divergence at different distances.
I know how cool it is to put something, like what you did, together.
Great I'ble keep going with it and put together a holographic table. You should have a lot of fun with your device.
Bye
Instead a volumetric book by testler was lodged at my library in scientific language.From the American library of Congress!
I can see how excited you were to put this together in your instructable.
How powerful is the finished laser?
(And I'm the only one who thought "Oh, light sabre!" when they saw the close-up of the lasing chamber?)