How to: make a dvd laser pointer
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Its a commonly known fact that DVD drivers use lasers to read and write data onto disks. Using this guide you will be able to harness the power of a dvd laser into a powerful, portable burning laser.
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Diode extraction
A laser diode is a small electrical component that emits a beam of unfocused light. In the united states, the legal limit of laser pointers is 5 mW. DVD burners contain laser diodes capable of producing over 150 mW of light.
Start by finding a 16X dvd burner. Lower speeds have less powerful diodes, and higher speeds have open can diodes. If you do use a open can diode, be careful to make sure to not expose it to static (walking across a carpet etc) and to wear a ESD wristband during handling of the bare diode.
Remove the outer case by any means necessary. You will see the laser assembly in the middle. It rides along 2 rails found on either side of the case. Remove the rails and pull out the assembly, begin removing random screws untill you find both laser diodes. One will emit a red light (650 nm) for DVD's and the other InfaRed light for CD's (808 nm).
Do what ever it takes to get the diode+heatsink out of the assembly. Every drive is made differently. Some times you will have to resort to using bolt cutters to carefully (kind of ironic...) remove pieces.
Once you get both diodes removed, begin by placing them face down on a work table. Use a small clamp to lightly hold down one side of the heatsink. Then, using a pair of slip joint pliers, apply pressure to the other side of the diode. With any luck, you should be able to pop the diode out of the heatsink without damaging it.
Repeat as necesary on the other diode.
Place the InfaRed diode aside (it will have a letter stamped on the back of it, the red one won't... in most cases)
Buying Diodes
The cheapest high quality diodes are available from http://sales.stonetek.org . Shipping is prompt and service is great.
Driver
The driver is the device between the diode and the batteries. It regulates the voltage and current supplied to it to prolong its life.
The most common driver uses a LM317 regulator chip (voltage regulator) and resistors (regulate current) to power the diode. It requires 6 volts to power (4x AA or 2x CR123) and works great.
This is a basic diagram of the circuit (credit to daedel at www.laserpointerforums.com)
Here is a basic rundown of the components
Laser Diode: produces the light 1N4001 Diode: Acts as a 1 way valve of sorts, makes it so if you supply current to the wrong end it will short the circuit, but won't interfere if its in the right way. Make sure its installed with reverse polarity or it will short the circuit every time. 47uf Capacitor: Can be any voltage (higher is better), absorbs any electrical spikes. LM317: Regulates voltage 100 Ohm Pot: Variable resistor Resistor: Resists
The 1N4001 diode is not required, but recommended just incase you do something stupid.
All the parts can be ordered from here for a grand total of $15.
With the driver, you should try and deliver anywhere from 120-350 mA of current. The more current, the more light and the more heat it will produce and the shorter the diodes life span. A heatsink can be used to counteract the heat produced and lengthen duty cycles. You should never go over 200 without the use of a heatsink and should never go over 300 without ThermoElectric Cooling+Heatsinking.
Mounting
Mounting a diode is simply installing it into the module (case) so its light can pass through its lense to become a laser beam.
Start by ordering an aixiz laser module from here, you can order it directly from aixiz but it costs more and will have slower shipping.
Unscrew the module and remove the lense/spring. Examine the head, you will see a circular opening into which the diode will be placed. Apply a very small amount of thermal paste to the hole and center the diode on top of it. You are now ready to press it in.
Pressing the diode requires alot of force that can't be applied to the pins. To do this, take the back end of the module (with the hole for the wires) and put the pins through the hole. You will now have a large metal cylinder pushing directly on the diodes base.
Put this whole thing (back end, diode, head) into a vice and squeeze untill the diode sits flush inside the module head. Remove it from the vice.
Soldering
The Laser Diode will have 3 gold colored pins coming from the back of it. When viewed so they are in a line, with the middle one higher than the 2 on either side, the one furthest left is POSITIVE and the middle is NEGATIVE. The right most pin is not used in this application.
Begin by gathering your soldering materials. You will need soldering flux, solder (no silver, silver raises the melting temp to require more heat), a low heat iron (under 25 watts) and something to hold the diode (a vice etc).
Begin by tinning your first wire. Apply a small amount of flux to the wire, heat it and apply solder to it untill it is well coated (not too much, not too little.) Repeat with the other wire.
Place the mounted diode/module head into the vice to hold it snugly. Make the pin you plan to solder first easily accessible. Apply a small amount of flux to the diode pin and tap it with the iron to make sure it spreads and the excess burns off.
Now were ready for the first connection. Touch the iron to just the lead you are connecting first. Wait for the solder to be come liquid and quickly stick the wire to the lead you want it attached to. Remove the iron once the wire makes contact with the lead, begin blowing on it immediately and hold the
Repeat with the second wire/lead combination and you're done
Tips
Try and solder the wire to only the top 3 cm of the lead, the closer it is to the diode the quick the more heat it will be exposed to. They are very heat sensitive, so any precation possible should be taken
Don't attempt this if your diode is not mounted in a module, as it will greatly increase your chances of burning it out. If you must try it, use thin wire (it will take less heat to heat up) and provide as much heatsinking as you can to the joint.
Don't rush it. Wait a minute between each application of heat to the diode.
Use flux. It helps the solder run and coat the pin better. A better and more efficient connection is made if used properly.
Apply thermal paste to the threads when screwing the module shut. The case will act as a heatsink.
Focusing
The lense in an aixiz module can be screwed in and out, making the beam convergent, straight or divergent.
Begin by making the beam straight. Screw the lense untill its about 3 mm from being all the way in, then power up the laser and continue making small adjustments untill you get a perfect beam.
For burning, unscrew the diode from this point. It will cause a focal point to form in the beam. The further you unscrew it, the closer to the laser the focal point will be. You can adjust the distance by pointing it at a dark object (reflects less) and examining the dot size from different lengths. After the light hits the focal point, it will begin to diverge and the dot will become huge over its path.
If you screw in after the beam point, the dot will diverge from the laser growing bigger with distance.
Uses
There are lots of fun things to do with a high powered laser pointer, including but not limited to:
- Popping balloons
- lighting matches
- cutting electrical tape
- burning wood
- stinging black peoples skin (it doesn't work well on white people)
- engraving plastic
- Turning off street lights
Burning tips
Try and get whatever your burning as close as possible to the focal point in the beam. The focal point has a huge amount of light in a super small area, making it possible to burn much better than the straight beam can.
If you find something that won't burn, use a sharpie (black maker) on it, then try again. Black absorbs heat and light much better than any other color.
WARNINGS!!
This laser will be MORE than powerful enough to blind someone permanently. Just looking at the dot from within a few feet can give someone a headache.
DO NOT under ANY circumstance attempt to shine it at a plane. Doing such is a major offence and can land you in jail, as well as endanger the lives of the passengers.
External Video Tutorial
Please DO NOT follow this guide. Its merely here to show you the power of these devices and the simplicity of their design. Connecting a diode to 2 AA's directly will kill it VERY VERY quickly. At the very least use a resistor or a potentiometer to limit the current if following this guide.
