Laser DIY rip off?

[rockrobotics]

A while ago I wanted to build my own laser,
so I went to www.laserdiy.com, and I was suprised to see
that the Laser diode driver cost $19.99!  I copyied the photo
over to paint and fixed up the picture a little, and it looked like
all it was was a couple of resistors and some other suff!  I know this is a robotics foroum really, but if anyone here knows about lasers you could tell me how to make a laser diode driver!  Thanks!

[waltr]

Yes, I do.
They are basically diodes that have a threshold voltage and are current controlled. But tend to have a very smaller current range and can be easy to 'burn out' or damage (been there). The expensive part of these 'cheap' lasers is the diode and the optics.

Try googling "LASER Diodes" and "LASER communication" to find webs sites on drive circuit details.


Here are a few from my bookmarks:
http://www.qsl.net/wb9ajz/laser/laser.htm
http://www.k3pgp.org/
http://www.roithner-laser.com/Drivers.htm
http://repairfaq.cis.upenn.edu/sam/lasersam.htm

These also have additional links for more info.

Also be sure to read and understand how to safely use these LASERs and what the Federal regulations are.

[rockrobotics]

Great!

Are you like a genius on everything electrical?

[cyberfish]

Out of curiosity, since I know nothing about lasers, what are the advantages of building your own when sparkfun has low powered lasers (including all the circuitry) for <$10? higher power?

[waltr]

Great!

Are you like a genius on everything electrical?

Absolutely not, just been playing with this stuff for close to 50 years.

[Soeren]

Hi,

Out of curiosity, since I know nothing about lasers, what are the advantages of building your own when sparkfun has low powered lasers (including all the circuitry) for <$10? higher power?

Quality.

Cheap LASER pointers usually has a crystal held sandwiched in a white metal holder and has no feedback system whatsoever.
A quality LASER diode has got a photo diode in the same housing, to measure emission, as there is a short span from the current magnitude where the LASER actually "lases" instead of just being an expensive LED and the current magnitude where it changes permanently into a weak but expensive LED by being burnt off (still giving off a faint red (non-"lasing") glow.

With the photo diode in a control loop, current can be precisely controlled within this narrow range.
It is not for the amateur to build a LASER supply however, as it needs to be absolutely transient free - a µsecond transient is enough to kill it off, so soft start is a must.

[Soeren]

Hi,

Absolutely not, just been playing with this stuff for close to 50 years.

Way to go waltr!

Especially in light of the fact that the first LASERs were constructed in the sixties and the early patents is from around mid.sixties to late seventies. And the semiconductor LASER discussed here is from the mid-eighties (i.e. around 25 years ago when talking protos)!

You must be one of the original inventors of the Ruby LASER I guess!

Now I'm really curious - how old are you really?! 

[waltr]

Oh, I do remember the magazines featuring Ruby LASERs. Later my brother and I got a hold of a surplus HeNe LASER tube, built a power supply and a voice modulator, all with vacuum tubes and other parts salvaged from old radios. Real fun stuff and sometimes do miss that high voltage that lets you know real fast when you mess up.

However my reply was to:

Are you like a genius on everything electrical?

Which wasn't a specific reference to LASERs. Just all this electrical stuff.

When LASER diodes become available at a reasonable price I did a bit of research and experimentation. Power supplies and modulators for LASER diodes are not too hard to build. The links I posted above has lots of good information on how to. Just expect to kill a few if the circuits are not good enough.

I'll let you guess on my age but I did start taking things apart at a very early age.
Another clue is I did see Sputnik orbiting.

Cheers

[Soeren]

Hi,

Another clue is I did see Sputnik orbiting.

Wow, you must be more far sighted than I then 

I actually think most folks here have at least had the possibility for an attempt, as the last Sputnik (smaller than the regular ones) was launched a little over a decade ago.

[rockrobotics]

Wow Waltr,

You must have started about at my age (12)!