new member :)

hey all!

ive been researching on these forums for the last few weeks and managed to build myself a red laser with a 16x samsung dvd writer diode and a home made driver, and i got a metal diode housing from dealextreme. i just thought id make an account and thank you guys for all the information this forum provides, and all the knowlege you guys posses on lasers!
a few minutes searching and i pretty much found everything i needed.

theres a couple of things im wondering about though, the laser i made is really bright, and shoots out for miles, you can see the beam at night, and faintly during the day. but it doesnt burn anything at all. if i shine it on black tape for a while with the beam focused into the smallest dot from about 3 inches away it starts to smoke, but no burning. im guessing i need to turn up the power of my diode via the trimpot on the driver. but the thing is, i turned it up to max, and its pretty much the same power. i didnt use exactly the same spec components as what you guys recommended (becuase i couldnt actually find them lol) but it should be powerful enough considering the brightness of the laser and distance it travels.

oh yeah, one thing i wasnt quite clear on was exactly how to test the power of your laser. theres some mixed results in the searches i did and im kind of confused. im guessing i dont need a test load circuit since ive got a diode already attached. do i just mesure the current across the resistors? >.<

i used 2 10mf resistors, if i remove one would that make it more powerful? im not exactly too sure. my voltage regulator isnt the lm317 you guys reccomend, but it does the same thing, it just has a wider range. so yeah its weird. ive attached some pics of my laser to show you.

any help would be much appreciated! and thanks again

-vinnie.

Welcome to the forum...:wave:

Nice first Laser build...

From what you say about the power of your laser...
do you have Laser Safety goggles...:undecided:

You can't focus a powerful laser to the smallest dot
(tightest focus) without Laser Safety Goggles....

We can burn black tape with as little as 30mW... if it
is focused properly...

BTW... if you see smoke.... something IS burning...

Jerry

ive got some laser goggles on way! i havnt been looking at the laser dot or anything, ive just been shooting it far into space and across long distances and stuff, only looking at the beam. and i see the reflection of the dot on the walls and stuff. when i shoot it onto black tape the dot becomes much less bright, and i only look at it through a camera thats hooked up to my pc.

ive been reading about the safety on these forums too and noone seems to be warning that much about the things that ive been doing. is it serious to be looking at the dot on walls and stuff?

As long as the walls or surfaces are not shinny/reflective you should be OK..
but it depends on the actual power of your laser's beam...

Safety first.... that's cheaper/easier than replacing your sight....


Jerry

Does the focusing module of your laser get warm at when you have the laser on for several minutes? You won't be measuring your current across any of the resistors you have, since the resistor usually referred to, is the 1 ohm resistor used in a laser driver dummy load. since you already have the diode connected, the safest way to measure its power output would be with a laser power meter. (LPM)

I haven't seen anything on the forum about the efficiency of samsung diodes, or who makes them, how they perform, etc. If you feel daring, you MIGHT be able to set your multimeter in series with your laser diode to measure current that way... but it might not be very safe..

If you want visibility, and burning power, I'd recommend an LPC-815 Long open can diode for your build, since they are cheap and powerful. For simplicities' sake, you might swap out your current driver for the more standardized LM317 circuit. There are all kinds of threads regarding this simple driver circuit.

you can use this graph to get a good idea about what kind of current you have on the LM317 circuit once you have set the resistance. PM me if you have more specific questions.