diy laser burner tutorial
TRANSCRIPT
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
Food Living Outside Play Technology Workshop
Cheap burning laser tutorialby Electorials on July 31, 2011
Table of Contents
Cheap burning laser tutorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Intro: Cheap burning laser tutorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Step 1: Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Step 2: The schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Step 3: What will the LM317T do? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Step 4: Some calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Step 5: Heatsinks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Step 6: Where to get your diode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Step 7: Diode assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Step 8: Assembling everything . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Step 9: Trying out your diode for the first time - tuning the diode current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Step 10: Creating a focussing system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Step 11: Any questions? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
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Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
Author:ElectorialsI'm really fascinated by science!From when I was young I've been curious about how stuff works and how I can create those things myself.Now I don't want to just learn things myself but I also want to teach everything to you guys!
Enjoy my instructables and have fun on my page ;-)
Intro: Cheap burning laser tutorialThis 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 like a 7805 are also possible to use here. If you have any questions about them, ask it here!
WarningIt 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 with a spirograph:
Image Notes1. Lens adjustment2. On/Off switch3. Current regulation (intensity)4. external input wires from a 9V adapter5. For switching between battery or external power source6. Really nice cases from velleman!
Image Notes1. See step 2
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Image Notes1. Piece from the potentiometer, the material is easy to break off. See step 10for this.
Image Notes1. woah! we even have space left! I could have chosen an even smaller case :)
Image Notes1. Holds the battery in place2. Overvieuw3. Push button4. ok... I'll just make this black :)
Image Notes1. Current limiting resistor - easy to replace - 2x 10ohm in parrallel2. wire is left long enough so that I can take out the circuit board easely3. Diode, protection against inverted polarity4. Battery / external input selection
Image Notes Image Notes
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
1. Current limiting resistor - easy to replace2. Audio connections, Very easy for plugging a wire in!3. For holding the battery in place4. Small heatsink for the LM317T5. Diode, protection against inverted polarity
1. Easy slide-on connection2. The other wire is soldered to the heatsink, which is also the negativeconnection of all diodes.3. For holding the battery in place
Image Notes1. Lens for focussing the beam2. Fixed with hot-glue, Very useful!
Step 1: RequirementsThe 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.
Image Notes1. See step 6 for where to get your diode
Image Notes1. 3x 10ohm - 250mW resistor = 5ohm 750mW Brown - Black - Black OR a
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
3.3ohm resistor - 0.5W
Image Notes1. You can use any regular diode that can hold at least 40V reverse voltage. Iused a 1N4004 because I couldn't find any 1N4001's anymore.
Image Notes1. 100ohm potentiometer
Image Notes1. On - On switch
Image Notes1. A lens. (maybe you'll find a good one inside a DVD/CD burner/reader).
Image Notes1. NEGATIVE connection!!! opposite from the battery. (If this note is in a weirdposition, re-ckick the image below here in the list)2. If you don't have one of these, there is also an instructable on how creatingone yourself from a dead 9V battery, link below here.
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
Image Notes1. This is the current regulator
Step 2: The schematicThis schematic is a little different from the ones you'll mostly find on the internet.
It doesn't use a capacitor for flattening the output voltage of the LM317T because the output signal is already perfect.It's also dangerous to use because when you remove the diode, the capacitor will charge to higher voltages as allowed for the diode, and when you attach it again yourdiode will be destroyed.
We also don't use an inverse parallel diode because that's not required. Your LM317T can't give negative voltages. Even if it did, the laser diode is a diode which meansit can take negative voltages (-2V).And even if your LM317T would somehow create negative voltages, your diode would die anyway because it means the regulator is broken; no current regulation meansdead diode. I don't see why people put diodes over there.
You can use a 9V battery or an external power input for this laser burner (choose between both with S1).
When using the battery, all is ok, but when you use the external input you should keep this in mind:If your diode works at around 4V and your voltage source is 9V then the LM will have to dissipate the remaining 5V by converting it into heat.Dissipating 5V is allright.The LM is made to handle a maximum voltage of 40VDC. If you would do that, and your diode still works around 4V then your LM will have to convert the remaining 36Vinto heat. This is possible - with an epic heatsink - but we want to keep things compact right?If you use a small heatsink and 40V input, then I ensure you your LM will be fried. (maximum junction temperature for the LM317T is 150°C, 302°F)
If you want to have an extra trim potentiometer for inside the casing, I suggest using a 50ohm potentiometer - 250mW.
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
D1 will be protecting our circuit from inverted polarity.D2 is the laser diode.R1 will protect R2 from being toasted (current limiter).R2 is the potentiometer which will control the current trough D2.Iadj is the adjustment current from the LM317T (see datasheet ).
Image Notes1. Laser diode2. Potentiometer - 100ohm - 250mW3. Current limiter to protect R2 - 3.3ohm - 0.5W4. Current regulator5. Polarity protection diode6. Push button7. Battery or external power source selection8. External power input (Read discription for when using more then 12V)9. 9V battery10. Adjustment current, information in datasheet11. Eventual power LED would go right here, in series with a resistor, 1kohm(when you use more then 20V as power source, use 2kohm)12. Eventual 50ohm 250mW current limiting trimmer potmeter for inside your case,would go here in series with the other pot. See description below.
Image Notes1. (picture without notes)
Step 3: What will the LM317T do?The LM317 makes sure that D2 (the laser diode) gets a constant current.- If the resistance of the diode decreases, and the voltage over it would stay the same you'd expect the current to raise, but the LM317T will then lower the output voltageso that the current stays constant.- Same when the resistance incrases- If the input voltage changes (increases or decreases) the LM will make sure the output voltage doesn't change.Example: Switching from battery to external input or having a flat battery
Notes: The output voltage can never be higher then the input voltage, so if your battery goes lower then 4V then the LM won't be able to keep a constant voltage at theoutput.
Other regulators like a 7805 are also possible to use here. If you have any questions about them, ask it here!
Image Notes1. This is the current regulator
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Step 4: Some calculationsGraphic 2 is with a 3.3ohm safety resistor, graphic 3 is with a 5ohm resistor. I changed from 5ohm to a 3.3ohm (3x 10ohm -> 750mW) resistor because it looked like Ididn't get enough current for my diode. I now suggest everyone using this new resistor value. The resistor must be rated at at least 0.5W. Other components didn'tchange.
What input voltage do we need (first picture)?At the amperage we're working with, the regulator needs a voltage differential of at least 3.5V between the Input and output pins. (graphic 1)This means:Supply voltage must at least be: 4V (diode voltage) + 1.25V (reference voltage of the LM317T) + 3.5V (minimum voltage between in and output pins, = Vdc)= 8.75V -> this is why we use a 9V battery, and not some AA batteries.
This is roughly calculated at the maximum ratings.
What happens when we go below that voltage? (when battery dies)As soon as we go below 8.75V the intensity of the diode will decrease, but our LM317 will still work untill the voltage drops below 1.2V (defined in the datasheet , howeverI don't understand why because it needs at least 1.25V between the 2 pins ).
What happens when we go above that voltage?See step 2 (40V)
Power dissipation in, and current trough the two resistors (second picture):As you can see in the graphic, the maximum current will be 378.8mA. That's when our potentiometer is set at 0ohm.The maximum power dissipation in the 3.3ohm resistor will be 473.5mW. This is why we use a resistor rated 0.5W (or 3 0.25W resistors).The maximum power dissipation in the 100ohm potentiometer will be 118.4mW. This happens at the moment when the resistance of the potentiometer is 3.3ohm, whichis the same as our protection resistor.
When the resistance of the potmeter drops below 3.3ohms, the power dissipated there will also drop because the voltage over the potmeter drops. (P = U*I)The power in the 3.3ohm resistor will keep rising until 473.5mW because the voltage over it, and current trough it will also keep rising.
As you can also see in the picture, the current will start rising from the moment we reach 20ohms and lower.From 20ohms and higher, the current doesn't change a lot any more. You will notice this effect when testing your laser: The laser will shine just a little until you reach thepoint of 20ohms or less, and then suddenly you'll think "oh, so my potentiometer Does work".I would like to use another potentiometer (47ohm or 50ohm) but I can't find them anywhere. We'll have to do with the 100ohm pot.
Another solution for this problem is to use a double potentiometer (2 of them, on one axis) and put them in parallel. You'll then have a linear 50ohm potentiometer.(I didn't have enough room for that now on my print-board, so I can't do that).
What to do when you've gathered an EPIC diode:High power diodes will probably work at higher voltages then 4V.You should look up the datasheet of the diode you have, and use this formula again to calculate the minimum power source voltage:
Vsource = DIODE_VOLTAGE + 1.25V + 3.5V
This is a reference datasheet if you can't find any: click!
Output current calculation:The output current can be calculated with this simple formula:
Iout = (Vref / (R1+R2) ) + Iadjor simply:Iout = 1.25V / (R1+R2) <- formula for your potentiometer
(where R1 is the safety-resistor and R2 is the potentiometer)
(because Iadj is several microamps, and Vref is 1.25V)(Iadj is indicated on the schematic, see datasheet for explanation)
Why 1.25V?Because the regulator will keep the voltage between pins OUT and ADJ at exactly 1.25V(1.2V to 1.3V, depending on the junction temperature)It's very logical how the current regulation works, it's just ohm's law. The whole regulation is all about the regulator trying to keep that voltage at exactly 1.25V
Examples:Potentiometer at lowest resistance:Iout = 1.25V / (3.3ohm + 0ohm) = 378.8mA-> current is now at it's maximum.-> Theoreticly we can have a diode of 380mA * -+ 4V = 1500mWIf you would like to have a diode with larger power, you'd have to choose lower safety resistor with higher wattage.You can ask me to make some new calculations and graphic of this in the comments below.
Potentiometer at highest resistance :Iout = 1.25V / (3.3ohm + 100ohm) = 12.1mA-> current is now at it's minimum.
Potentiometer at lowest resistance, without protection resistor R1:Iout = 1.25V / (0ohm + 0ohm) = infinite mA (theoretically)-> your diode is now fried.(the current will depend on the maximum current and voltage your supply can deliver and the resistance of the diode, so it won't be infinite but your diode will be anyway).
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Image Notes1. Imax = 250mA so Vdc is something like 3V (we take at least 3.5V to calculatewith)2. Image copyright -ON Semiconductor-
Image Notes1. Maximum current will be 378.8mA2. Maximum power in 3.3ohm resistor will be 473.5mW3. Maximum power in the 100ohm potentiometer will be 118.4mW
Image Notes1. Maximum power in the 5ohm resistor will be 312.5mW2. Maximum current will be 250mA, as calculated below here3. Maximum power in the 100ohm potentiometer will be 78mW4. This is when you use a 5ohm current-limiting resistor. The maximum current willbe lower now. This is for lower-power diodes.
Step 5: HeatsinksI'm not going to calculate those here because if you read the text on the previous page, you know what to do to keep the junction temperature of the LM317T low.However! That doesn't mean you don't need a heatsink.I'm not going to calculate the size of it because even the smallest heatsink existing on earth is enough for the regulator :)
(using NO heatsink is possible, but you have to Really know what you're doing with the input voltage. Even I added a heatsink for if the input voltage would accidently betoo high. I'll save my circuit from being fried for a few moments so that I have time to interact)
If you Don't have a power source with a fitting voltage, you'll need to have a larger heatsink, but I suggest you just try some different heatsinks untill you found a goodone.
Ok, so far for the LM heatsink.The diode needs a heatsink too!
This little guy will create most of the heat in the whole circuit, so this is the one who actually needs a good heatsink.do not overreact like on the pictures I find on google (like this one or this one )The heatsink I took for my diode is also too large because it never gets warm. I just took it because it was the only one I had (See picture above)
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Step 6: Where to get your diodeFollow the steps in the pictures above :)
Different types of diodes:Low power IR diodes are found in CD readers.High power IR diodes are found in CD burners (CD/RW).Low power red diodes are found in DVD readers.High power red diodes are found in DVD burners.Low power violet (blu-ray) diodes are found in blu-ray readers and HD DVD players.High power violet (blu-ray) diodes are foind in blu-ray burners and HD DVD burners.
For example, I will be extracting a laser diode from a DVD burner. Take a look at all the pictures above here to see how to do it. Instructions are added with the yellowtags.
Note: Red DVD burner diodes are mostly used for laser burners because they are the best diodes that you can find most easely.Don't expect to find a blu-ray burner diode somewhere
Warning:IR (infra-red) diodes are just as dangerous as other diodes, but the difference is that you can't see the danger!It would be really stupid to think that when you see just a little light, that it can't burn your eyes!
Again: Wear protective glasses!
Image Notes1. Step 1: Take your reader/writer (I have this LG CD burner)
Image Notes1. Step 2: Take the bottom side off and remove the print boards
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Image Notes1. Step 3: Cut off some pins
Image Notes1. Step 4: 2 pins is enough but you can take some more for reserve
Image Notes1. Step 5: Pull them out with pliers
Image Notes1. Step 6: Pull them out with pliers
Image Notes1. Step 7: :)
Image Notes1. Step 8: Flatten them
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Image Notes1. Step 9: Bend this cover to easily take it off.
Image Notes1. Step 10: This is the part we need.
Image Notes1. Step 11: Remove as many screws as you can. Our diode is somewhere inthere.
Image Notes1. Oh look, I found it!2. A lens3. Diode holder and heatsink, do not throw this away!4. Step 12: This was indeed all inside that tiny thing. Throw away everythingexcept for those three things. There are also some neodymium magnets inside.
Image Notes Image Notes
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1. Step 14: De-solder this 1. Step 15: Admire your new diode :)
Image Notes1. It looks like I found a nice infra-red diode. (in real life it doesn't shine sobright because we can't see the infra-red light).
Image Notes1. It was doomed to be burned!
Image Notes1. All happy!
Step 7: Diode assemblyMany disc burners have these diode holders inside which are perfect for our laser burner, so if you find this inside, Don't throw it away!Because the diode fits in there tightly, the heat exchange will go really easily, and since these things are round, so we can just drill a hole in our heatsink and push this in.
Picture 2,3 and 4 show which pins have to be connected. Soldering might be hard when the pins are really short. When you solder, make sure the diode doesn't get toohot! Solder quickly.
You can now use the connector from picture 5 to connect the positive pin from the diode to your circuit.If you've connected your negative wire to the heatsink, you don't need to connect a wire to the negative side of the diode.That pin is the same as the case.
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Image Notes1. Diode fits perfectly in here
Image Notes1. Solder on the pin you've collected from the writer/burner.
Step 8: Assembling everythingThe easiest way to make holes in your plastic box, unless you use a drill, it with a scissors!First make a small hole with anything, and then make the hole larger by rotating your scissors in there.This way you can have all sizes for you hole you want to.
You'll have to make a big hole for the potentiometer, a small one for the push-button, and another small one for the switch.Then a hole for your laser diode and maybe some holes for your external power connector.
Assemble everything, and don't forget to leave some room for your battery!
You can use a plastic piece like I did, for fixing the battery in place. (glue in the box with hot-glue or super-glue).
For all other components, you don't really need a print-board. You can just solder them together in the plastic box. (like I just soldered the diode to my push-button).
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Image Notes1. Easy slide-on connection2. The other wire is soldered to the heatsink, which is also the negative connection of all diodes.3. For holding the battery in place
Step 9: Trying out your diode for the first time - tuning the diode currentDo not test your diode with a simple circuit to see how cool it is, but just first make the real circuit and then test it.Believe me, the chance is really high you'll just kill your diode if you have no experience with laser diodes.
- Make sure power is disconnected.- Place the diode inside the heatsink and not outside because it will probably get broken from overheating.- Make the connections from the circuit to the diode.- Wonder why, but accept that you don't need a lens yet.- Turn the potentiometer to the Highest resistance.- Turn on the power.- SLOWLY decrease the resistance of the potentiometer by rotating it.- The diode will slowly start shining brighter.- Suddenly it'll go shining brighter really fast when you just turn a little.- This is the moment when you really don't want to go too far.- If you don't want to risk killing the diode, stop here.- Rotate a little further -really carefully - until the brightness stops increasing. Stop there! don't go any further.- When light intensity starts decreasing a little, go Back immediately, but not too much, just a little until it goes back to the highest brightness. (it means you went a littletoo far, but if you turned very slowly, you probably didn't damage the diode).
Another, more precise method is to look at the line pattern of light (see pictures of the red diode above) that your diode emits.Usually, the pattern shouldn't change when you increase the current trough the diode.When you suddenly see it starts to deform, that's the moment that -if you go a little further - your diode is broken. Like in the other method, go back a little as soon as yousee the pattern is deforming. It'll be perfectly adjusted.This second method doesn't work on all laser diodes because not all of them show line patterns like this.
Image Notes1. Line pattern of a 445nm laser diode
Image Notes1. These three pictures show Exactly what I mean with deformation of the linepattern. (this is actually a broken diode, but perfect for showing this!)
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Step 10: Creating a focussing systemThis step is still under construction, I will be adding more pictures here soon!
I had a little thought about how I could create a simple thing to adjust the focal length of the beam.I came up with this great idea to use a broken potentiometer, Recycling ^^!
So you need a potentiometer, two screw nuts, or at least one (it's probably already screwed on the potentiometer) and a nipper.
- Take the potentiometer apart with the nipper.- Don't damage the screw-thread.- Break off the remaining metal, leave only the piece with the thread.- Take your lens and glue it on the piece with the thread.- When using super-glue, make sure the glue fumes don't corrode the lens. You risk colouring the lens blurry-white! -> solution is to keep blowing on the lens to lead away the fumes.- Make sure you glue the lens perfectly in the middle because else the laser dot will rotate when you adjust the focal length.
- Screw the nut till the middle of the thread.- Hold the lens in front of your, turned on, laser diode.- Measure the distance from the nut till your project box at the moment the beam is focussed as small as possible at a large distance.- Find a short tube that just fits around the thread without tension. -> A plastic pen is good for this.- Cut the tube to the measured length, and make sure it's perpendicular.- Glue the nut on to the tube.- glue the tube on to your box, exactly in the middle of your laser diode- Done!
Now what's the use of that second nut?The second nut is for fixing the lens in place. If you would only have one nut, the thread will start moving when you pick up your laser.
Image Notes1. This part is what we need2. This breaks off easely
Image Notes1. Read instructions below.
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Image Notes1. Tube from a pen
Image Notes1. Screw this nut downwards to fasten the lens
Image Notes1. Piece from the potentiometer, the material is easy to break off. See step 10 forthis.
Step 11: Any questions?This step contains some pictures of the laser in action. All pictures above were made with a DVD reader diode. It's still very bright though.Also: No, this laser doesn't make a super bright line of laser light, but that's because I don't take pictures in a bathroom full of vapour.
If anything is not clear to you, don't hesitate to ask it here!All questions are welcome, I'll try to answer them as fast as possible.If you like this tutorial, please comment!
Oh, and if you think something in this tutorial is still missing, also just tell me here ;)
Have fun and be safe!
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Image Notes1. Glowing finger haha!
Image Notes1. There was a little fog outside, this laser doesn't really shine That hard that youcan see the beam in normal circumstances. It's just a DVD reader diode. When Iget a DVD burner diode the results will be epic :D
Image Notes1. (There's this small crack in the side of my lens but it still works pretty fine)
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Comments
48 comments Add Comment
jdougherty2 says: Aug 4, 2011. 1:06 PM REPLYAbout how long does it take for the laser to start burning? I notice you're shining it on your finger in a couple pics, so i'm guessing that it takes a bit. Also,would this sort of setup be decent to attach to a CNC machine for at-home laser cutting, or is the laser not quite powerful enough?
Electorials says: Aug 4, 2011. 2:34 PM REPLYThe laser I'm using in those pictures is a DVD reader diode. It does't get warm.
This setup (electrical) would be good for a CNC cutter. The mechanical setup (the project box) wouldn't be handy.
If you get a powerful diode, you could use this tool for cutting stuff on a CNC machine but it won't cut thick things.
Real CNC cutters use CO2 lasers (we're talking about certain Watts then, like a 40W CO2 laser), and the lasers in this project are limited to 1500mW.
A 1500mW can also cut things, but not thick stuff. (a CD case would be possible, to give you an idea of the thickness)
gwhizz says: Aug 4, 2011. 8:58 AM REPLYHi Electorials,Can I use a 7805 instead of the LM317T, as I have some lying around?
Electorials says: Aug 4, 2011. 9:16 AM REPLYHello gwhizz,
It is possible yes.That voltage regulator can also be used to regulate current, and with a maximum current of 1A it's no problem.
You'll have to change the safety resistor of 5ohm with one of 20ohm.The potentiometer may stay at 100ohm.
I've added an graphic for you with all things you need to know.
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
gwhizz says: Aug 4, 2011. 9:39 AM REPLYMany thanks
Electorials says: Aug 4, 2011. 12:26 PM REPLYuhm..
I'm really sorry but it looks like I did something wrong with the previous calculations :/
I have 3 suggestions:
- Imax = 340mA - 2W 15ohm resistor - 220ohm potentiometer (picture 1)(great burning laser. Disadvantage is that you need a 2W resistor. If we would use a smaller one, it would burn instantly).
- Imax = 280mA - 1.5W 18ohm resistor - 150ohm potentiometer (picture 2)(medium laser but still a 1.5W resistor :/).
- Imax = 180mA - 1W 27ohm resistor - 100ohm potentiometer (picture 3)(disadvantage: weak laser).
Conclusion: it's possible with a 7805 but we need large resistors. Your battery will also drain faster.
You'll have to choose which of the three you want ;)
Electorials says: Aug 4, 2011. 12:32 PM REPLYhttp://i.solidfiles.net/8555d.pnghttp://i.solidfiles.net/e92ea.pnghttp://i.solidfiles.net/fa641.png
Electorials says: Aug 4, 2011. 9:21 AM (removed by author or community request)
Electorials says: Aug 4, 2011. 9:31 AM REPLYAnd like the calculations in step 4, this is what you should do:
Supply voltage must at least be:
4V (diode voltage) + 5V (reference voltage of the LM317T) + 2V (minimum voltage between in and output pins)= 11V
I suggest using a 12V supply or battery.
lgonzalez mejia says: Aug 4, 2011. 12:20 PM REPLYobjects used to burn
Electorials says: Aug 4, 2011. 12:28 PM REPLYWhat do you mean?
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
Electorials says: Aug 4, 2011. 11:53 AM REPLYCurrent-limiting resistor changed to 3.3ohm. Read step 4 for more information.
digas says: Aug 2, 2011. 2:40 PM REPLYEvery time i disassemble a dvd burner i get the diode , but the diode does not work! Any suggestions?
Electorials says: Aug 2, 2011. 2:51 PM REPLYDid you solder anything to the diodes before you tested them?maybe the heat of your soldering iron kills the diodes :/
digas says: Aug 3, 2011. 2:13 PM REPLYnop, no solder!
Electorials says: Aug 3, 2011. 2:20 PM REPLYand other diodes do work? or did you only try dvd burner diodes yet?
digas says: Aug 4, 2011. 2:42 AM REPLYonly tried dvd burners!
oppie says: Aug 4, 2011. 6:56 AM REPLYThe laser diodes I've worked with are three terminal devices. One pin is the common. One pin is the laser diode and the other pin is aninternal photodiode that monitors the laser output. Idea is to run the laser in closed loop at a stable optical output.
A laser running at very low current is no more than a LED. As you increase the current, light gets brighter and starts to transition tocoherent radiation (LASing). The difference between the lasing threshold and overload where you destroy the diode out is rather small,hence the desire to use a closed loop optical feedback. This also compensates drive current for die temperature variations.Typical diode datasheet http://media.digikey.com/pdf/Data%20Sheets/Sharp%20PDFs/GH06510B2A,B.pdfSome good applicatoin information http://www.repairfaq.org/sam/laserdps.htm
Electorials says: Aug 4, 2011. 7:26 AM REPLYWhat you say is true, but I don't really see how it helps digas?
And that last link is indeed very useful ;)
oppie says: Aug 4, 2011. 9:47 AM REPLYSorry, I got distracted and had meant to add that he might have connected to the monitoring diode instead of the laser diode.Would be plausible reason why there was no light output but current being drawn.
Laser diodes are also rather sensitive to heat, mechanical shock and static discharge.
Electorials says: Aug 4, 2011. 9:52 AM REPLYAhh ok ;)
Electorials says: Aug 4, 2011. 3:50 AM REPLYThen your diodes are probably not broken. I hope you didn't throw them away!
Could you tell me something about what driver, what pins on the diode (and polarity), power supply, resistors (if LM317), ... you are using?
(if you want to, you could also send me some pictures of the setup. it'll be easier for me to understand then).
kangooooooo says: Aug 4, 2011. 8:58 AM REPLYThis is exactly the level of quality for an ible on lasers I was looking for!
Thanks a lot Electorials.
Electorials says: Aug 4, 2011. 9:24 AM REPLYThank you!
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
orksecurity says: Aug 2, 2011. 7:30 AM REPLYSuggestion: Once you find the "ideal" position for the potentiometer, you might want to consider using a drop of fingernail polish to hold it in that position, soit's less likely to shift accidentally. (In lieu of glyptol, an enamel paint that's often used for the same purpose.) It'll break free easily enough when you _do_want to turn the knob.
Also, I'd be tempted to put either the whole potentiometer, or a "trim" potentiometer to calibrate this one so it can't exceed a safe limit, _inside_ the box --again, to protect against accidentally turning the knob that one step too far.
Nice straightforward design.
One quibble: I HIGHLY approve of the calls for safety glasses (a bright laser can do a significant amount of damage to eyes with NO warning) ... but I wishfolks would point to sources for glasses suitable for each frequency range. I'd also recommend that folks using these seriously consider "beam stops" --barriers to ensure that there is Absolutely No Way the laser beam can reach anyone else, in any direction (including by reflection, and including overhead).
Electorials says: Aug 2, 2011. 12:59 PM REPLYHello,
I had an extra safety potentiometer on my previous laser burner. (with exactly the same function as you say).
I don't know why, but I just really forgot to add it to this laser too :/I'll probably change it in the instructable. Thanks for reminding me of it!
Putting the potentiometer inside the box might be a good idea but I more like to be able to adjust the intensity without opening up the box.(The extra potentiometer inside the box you said, makes this unnecessary).
"I wish folks would point to sources for glasses"I don't really know what you mean with that, do you mean the sources for where you can buy them? (because I really have no idea).
Also, how does a 'beam stop' work? I don't have it, and I can't find good information about it on google because I find many different systems that arecaled 'beam stops' :/
orksecurity says: Aug 2, 2011. 1:15 PM REPLYBeam stop: Essentially just a matter of, while you're setting up whatever you're using the laser for, make sure that the beam, and any possiblereflection or refraction, hits a solid object before it hits anything you don't want it to hit. Good safety practice.
Glasses: Yes. Everyone -- myself included -- keeps pointing out that they're a good idea but none of us -- myself included -- provides specificexamples of which glasses are appropriate for which lasers or where you can get them. One of us should doublecheck exactly what the frequencyranges are of each of these common "rescued" LEDs and provide examples of what to order and what to websearch to find them. Llab safetysuppliers generally do sell these in onesie-twosie quantities are fairly reasonable prices; I bought a pair of cheap plastic UV-blocking safety glassesMANY years ago... but you need to know what to order.
kevinhannan says: Aug 4, 2011. 7:48 AM REPLYA really lovely old teacher I used to have tried to instil into his students that accidents don't ask if they can be allowed to happen. He also saidthat you should/must arrange your workspace so that safety is built-in. In his memory, (and I do think of him and thanked him) I have safetyglasses in a pouch hanging from the lock on my tool-box, safety glasses in my PPE (personal protective equipment) box which is the very firstbox I must touch before I can access the other boxes and safety glasses in my other storage space for gardening tools.
Thank you, kind Sir; there are many people who have you to thank for their continuing use of eyes and limbs. I shall continue to spread your wisewords and wise work.
I applaud Orksecurity's words. If there's only *one* item of safety equipment you buy, make sure it's the right glasses/eye-wear protection. It'sgreat fun to do great projects, so let's all keep it that way.
Electorials says: Aug 2, 2011. 2:57 PM REPLYTomorrow I'm going to look up stuff about these safety glasses. Types of glasses, how they work, which ones to use for which lasers, ...I also don't know a lot about them. I'll tell you what I found.
Greetings,Electorials
rkey says: Aug 4, 2011. 1:14 PM REPLYcheck out Thor Labs they are expensive but at least they are certified. http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=762
Also make sure you know what wavelength the laser diode your are using is:
http://en.wikipedia.org/wiki/File:EM_spectrum.svg
DVD uses a 650 nm wavelength laser diode
780 nm for CD
and
405 nm for blue ray
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
Electorials says: Aug 4, 2011. 2:30 PM REPLYThanks ;)
Electorials says: Aug 4, 2011. 4:00 AM REPLYThere's not much to find about how they actually work.I als don't know where to buy them in my country.
Which glasses for which lasers I did find.
killersquirel11 says: Aug 4, 2011. 8:24 AM REPLYMost laser safety glasses work by blocking a certain frequency range of light. You pick the glasses which block the frequency of your laserand you should be protected. If you (as a test) shine the laser through the glasses, they should block the beam, although with that highpower of a laser, you might damage the glasses by testing this.
Electorials says: Aug 4, 2011. 8:34 AM REPLYYes, but how does that 'frequency blocking' work?
ryanmercer says: Aug 4, 2011. 9:35 AM REPLYSame way sunglasses block UV rays. The laser safety glasses are just blocking the spectrum of the laser, instead of the spectrumof UV.
Electorials says: Aug 4, 2011. 9:45 AM REPLYbut do you know how a piece of coloured plastic can block a certain frequency?
Is it special plastic? A special coating? Just coloured plastic with nothing else? ...
ryanmercer says: Aug 4, 2011. 10:07 AM REPLYSame way any other optical filter works... and there are many methods of doing it. Go read the wiki article on optics filtershttp://en.wikipedia.org/wiki/Filter_%28optics%29
fjohn says: Aug 3, 2011. 3:28 AM REPLYhey i have a cd reader and.......u told that have ir diode which is low power so does it burn or atleast burst a balloon within secondss??????
Electorials says: Aug 3, 2011. 3:42 AM REPLYI haven't tried CD reader diodes yet. All I know is that a CD burner diode does it easily.
I don't really think it's going to work but you could give it a try :)
chaddv79 says: Aug 2, 2011. 3:12 PM REPLYwould this work with 532nm green laser diode?
Electorials says: Aug 2, 2011. 11:04 PM REPLYYes ;)
PS118 says: Aug 1, 2011. 1:13 PM REPLYWhat kind/how thick of stuff can you burn with it?
Also, since you asked, I'd like to request pics/videos of this thing in action!
Electorials says: Aug 1, 2011. 1:48 PM REPLYHello,
The intensity of the laser depends on what diode you are using. I currently don't have a good diode, I'm using one from a DVD reader.
It's already very bright but I know a DVD burner diode would be even 10 times better.
so if you're asking what thickness of things it can burn, I don't really know that yet.but again, it really depends on the diode. If you can find an epic diode, you would be able to burn trough cd cases very easely.
the best diode for burning I could test with was the infrared cd burner diode from the pictures in step 6.It can cut electrical tape.
The laser was designed for epic diodes. It can (if you find such a diode) deliver 1000mW of power for a diode, and beleave me, a 1W diode is reallybright!
I'll be posting pictures or a video for you, but I can't right now because I'm not at me pc, and tomorrow I'm not at home.So in 2 days I'll grab my camera for you ;)
http://www.instructables.com/id/DIY-Laser-burner-tutorial/
Electorials says: Aug 2, 2011. 1:24 PM REPLYOk, I've added some pictures for you in step 11.
I know the diode isn't really cool, it's just a DVD reader.It's still very bright though.
When I get my DVD burner diode I'll post new pictures ;)
kgrewe says: Aug 2, 2011. 10:33 AM REPLYFirst off nice job. I haven't looked through the whole project yet but I really appreciate all the pictures so far. It takes more time but it really helps a beginnerlike me understand. Thanks for the work.
Electorials says: Aug 2, 2011. 1:00 PM REPLYNo problem, Thanks ;)
rimar2000 says: Aug 1, 2011. 8:46 PM REPLYThis is very interesting, thanks for sharing.
Electorials says: Aug 2, 2011. 1:00 PM REPLYThank you!