Instructables
IMG382.jpg
IMG384.jpg
IMG386.jpg
This tutorial will explain every little thing you need to know about how to build a burning laser, it's an interesting project, which is still quite easy to make.
The picture above shows how mine looks but you can make the design of yours look totally different if you want to.

It's going to become a burning laser with controllable current. (current-regulated with an LM317T).
You can choose between a 9V battery and an external power input (see first picture on the left side).

Other regulators then an LM317T are also possible to use here. If you have any questions about them, ask it here!

Warning
It might be fun to have a burning laser, but not when it burns that one thing you don't want it to burn.
Use safety glasses! This is really not a simple toy.

High power lasers might also not be allowed in your country, keep that in mind.

I am not responsible for any accidents with this device, however all dangers are well noted in this instructable.

A video of the laser in action:


A video of the laser in action with a spirograph:
 
Remove these adsRemove these ads by Signing Up

Step 1: Requirements

The set-up is really simple, there are just few components:
(* means Required)

- Hot glue or other glue.
* A soldering iron /w soldering wire.
* A laser diode.
* A 100ohm potentiometer. (250mW)
* A 3.3ohm resistor (or 3x 10ohm resistor in parallel). (3x 250mW or 1x 0.5W).
- A regular diode 1N4001-1N4007 (everything between is also good).
  (or any other diode that can hold a reverse voltage of at least 40V)
- An On-Off switch/push-button/... as a main switch for the circuit.
- An On-On switch for switching between battery or external input.
* A 9V battery clip. (click here if you don't have one)
- A 9V battery. (not required if you use the external power input)
* An LM317T regulator (really cheap).
- An enclosure/box to put the whole project in -> I used an 8*5*3cm = 3.15*1.97*1.18inches black project box.
* A lens for adjusting the focal point of the laser beam.
- A connector for the external power input (if you want to use that).
* PDF reader for the datasheets.
* Your healthy brain and attention for safety measurements.

1-40 of 197Next »
iamdarkyoshi2 months ago

i should be able to connect the diode straight to my lab supply, right? i can tune the supply to the hundredth of a volt and the thousandth of an amp.

Pbyrd1 year ago
Would a 7805 regulator work here?
djmelvinv Pbyrd4 months ago
a lm7805 is a voltage regulator not a current regulator.
Electorials (author)  Pbyrd1 year ago
Not really. The voltage over the potentiometer and resistor (5v in this case) would be too high. When you increase the output current, the power dissipation in the potentiometer will just fry it.

In the instructions it said you could use one.

Fireturkey885 months ago

Where can I find an lm317

glitvjaks5 months ago

Great instructable! Easy to follow but not dumbed down. I used your circuit today to make a laser spirograph (although I am using a laser module meant to be powered by batteries instead of a bare laser diode) and it worked just fine!

djmelvinv5 months ago
hi. is a dvd diode exact the wavelenght of 650nm or is there an range? I just want to find the glasses maching de dvd burn diode wavelength and want to be very sure there is no IR.
metalshiflet6 months ago

I looked in Radioshack and could not find a 3.3ohm resistor. What other names are there for it?

metalshiflet6 months ago

How can I convert this to work on a battery bank with 4 AA batteries? I'm making a laser gun and there is already a space in the casing for this bank. I would rather use that than a 9V. Or, better yet, convert it so that it can alternate use between the 9V and the battery bank.

ir_One7 months ago

Hi , i have cd burner,..are its can be used for laser burn...?

kgaurkhede8 months ago

heyy
plz help me to make a circuit for powerful laser which can burn plastic sheets of almost the thickness of 3-4 paper sheets
n of what power the laser diode should be???

thnx in advance

kgaurkhede8 months ago

heyy
plz help me to make a circuit for powerful laser which can burn plastic sheets of almost the thickness of 3-4 paper sheets
n of what power the laser diode should be???

thnx in advance

mkhurram9 months ago
Hey electorials! Loved the instructable.....can this thing cut acrylic ,plastic boxes etc. as well??
im using a diode from a dvd burn... but it not burn!!! why? can you help me? im usin a circuit with LM317
cool gonna make one
dudefrom981 year ago
I got 6.88 volts as the output to go to the laser. Is this fine or should I put a regulator on it?
Can i use a 1n4148 diode instead of the 1n4007?
Hey,
You can use it, but because the maximum current is only 200mA, if you will be using strong laser diodes, I suggest you put two 1n4148's in parallel, so that they can handle 400mA.
SpecieS~2 years ago
Hi, I'm wondering about the limiting potentiometer. Do you connect it exactly like the one for regulating the intensity? And do you still use 100ohm for regulating or do you change the value?

greetings, SpecieS
Electorials (author)  SpecieS~2 years ago
hi,
I still use the same value, 100ohm (but I think 50ohm would be a little better, not sure).
It is indeed connected exactly the same, and placed in series.
Thanks for your fast answer. I found some 50ohm 1/2watt precision trimmer, which would be perfect for the limiting job :D
A 300ohm resistor in parallel to the regulating potentiometer would reduce its maximum resistance to 75ohm. Seems to be a good compromise :)

greetings, SpecieS
Electorials (author)  SpecieS~2 years ago
huh?
You say 'reduce' it's maximum resistance, but you say it goes from 50 to 75 then?

Indeed, a 50ohm trimmer would be nice.
When adding a resistor in parallel over it, you'll Decrease it's resistance, not increase to 75.
And also, when you added a resistor in parallel, the track resistance won't e linear anymore.

You don't need to add a parallel resistor, the 50ohm trimmer is perfect.
Oh, you misunderstood what I said. I don't want to decrease the trimmers resistance but the regulating potentiometers resistance from 100 to 75ohm.
Electorials (author)  SpecieS~2 years ago
Ahh yes, I see now.
but I don't think you'll get "more precision" out of it by doing that because it will make the slider non linear.

At the lowest resistance values, it will change faster now.
Indeed, it makes it non linear, but I've inspected the function in kmplot and the graph is almost linear: http://img836.imageshack.us/img836/6051/resistancegraph.png

btw, I've made some new schematics including the second potentiometer using Eagle: http://img845.imageshack.us/img845/3899/schematicslaser.jpg
You may attach it to the instructable if you want.
Electorials (author)  SpecieS~2 years ago
It al looks really good.
The schematic is also good but I think I'll just keep the one that I already have.
My parts arrived today and I tried it out on a breadboard. The trimmer became hot so I removed it, but then turned the other poti a bit too far. :S
Fortunately I have another dvd-burner laying around...

ps: Happy new year :)
Electorials (author)  SpecieS~2 years ago
The trimmer's power rating must have been to low.
I hope you got some nice results before the diode got fried? :)

Oh, and it's normal that you fried your first diode. You'll do that 10 more times haha! :)

Happy newyear!
Well, according to the datasheet the trimmer's power rating is 0.5 watts at 70°C decreasing linearly to zero at 125°C. But obviously my diode exceeded this limit ( I suppose it was about 0.7 watts or more). I think next time I'll use the big poti to adjust to the right resistance, measure it and use some resistors in parallel to set the minimal resistance.

And I hope I don't need ten tries to build a working laser :D
Electorials (author)  SpecieS~2 years ago
Tell me,
How is your laser now?
did it work out? :D

Greetings,
Electorials
Hi there,
it works, but I don't have a collimator yet. I've already tried focusing the beam with a single lens, but it didn't burn anything. Maybe the diode is too weak. It's a bit smaller than usual, because it's from a laptop dvd-burner.
IMAG0142.jpg
Electorials (author)  SpecieS~2 years ago
Wow! it's looking really good :D
It's nice to see that other people are also making this ;)
Good to see a picture of it!

And yes, the diode is probably just too weak.
However, DVD burner diodes should do the trick
Maybe it can handle more current than you are giving it now?
Hey, I finally made some pretty simple optics from a ball pen and one of those lenses I kept while taking apart the drives. I also made a "quick 'n dirty" double-slit out of paper. The second picture shows it's interference pattern :D
IMAG0413.jpginterferenz.JPG
Electorials (author)  SpecieS~1 year ago
That looks awesome :D
Today I tried out some other materials for double-slits. Aluminum foil worked quite well, so I finally decided to make an 'ible of it :)
How To Make a Simple Double Slit
digas3 years ago
Every time i disassemble a dvd burner i get the diode , but the diode does not work! Any suggestions?
nbeched digas1 year ago
Just to add:
It's either the heat from the soldering iron or static discharge that very quickly destroys the diode. It doesn't have to be a massive/powerful discharge that you feel...

The safest thing to do is when you desolder the diode, solder or wrap a piece of wire to both pins so that they are always at the same potential and remove this wire right when you are ready to solder something else to it.

Also, don't forget that it is a diode, so it is polarised, meaning, if it does not work, try reversing the +/- to it.
Also, if you don't use the LM317 method described here, have some series resistor as supplying too much voltage will kill it just as quickly as a static discharge...

Have a good one.
Electorials (author)  digas3 years ago
Did you solder anything to the diodes before you tested them?
maybe the heat of your soldering iron kills the diodes :/
nop, no solder!
1-40 of 197Next »