I am going to go through the entire process from start to finish in creating your own DVD burner laser pointer. This will allow you to build your own laser pointer from a dvd burner capable of burning and cutting. I welcome feedback to this review and if I have left anything out please email me at email@example.com
What you will need.
1 DVD+/-RW. I do not know of any other brands of dvd burners that are going to net you a good solid laser diode other than the oneís listed here: http://www.candlepowerforums.com/vb/showthread.php?t=166188
A flashlight. Mini Dorcy purchased from Target, Dorcy Metal gear purchased at walmart, MiniMaglite or various other flashlights. I will only be showing the three flashlights for time saving purposes.
An Aixiz Laser module found here: http://mfgcn.com/_wsn/page2.html You will want the 650nm 5mw 12mm X 30mm full brass case $4.50 USD.
Soldering iron. I use a Weller 25W soldering iron. Solder.
Small set of nut drivers available at radio shack.
Multi-meter with diode checking ability.
Assorted things including batteries, black and red sharpie pen, some side cutting wire dikes.
Once you have assembled all the things you will need sit down with a screwdriver and a bit of time to pull apart the DVD burner to harvest the laser diodes. Remove the screws from the casing to get to the guts. Inside you will see a circuit board usually just resting inside. Remove the board and toss. You will then reveal the sled and all of the components we are looking for. Remove the screws holding the rails in place and slide the laser assembly off the rails. Slowly taking your time not to damage anything valuable remove all the screws and pieces off of the assembly until you are down to the bare metal housing the diodes. I never remove the cabling off of the diodes until I have them out of the metal housings. This is where I take out my Side cutting wire dikes and nip away the metal around the housing. I use several sizes to make sure Iím cutting away the metal and nothing else (like the diode.) BE GENTLE. DONíT RUSH. Take your time doing this. Nothing is gained by going quickly. When you have removed all of the metal around your diode take heatsink pliers from radio shack (these are made from solid aluminum) and place them on the diode pins you are going to de-solder one at a time. With your soldering iron and a wick remove the solder from the pins and toss the connector. I always use a fair amount of rosin in the wick to make sure I get all residual solder from the pins quickly. Heat is an enemy to the diode hence the reason we are using the heatsinking pliers. Use a very quick touch to the pin then quickly remove the solder off with the wick. TOO MUCH HEAT WILL KILL YOUR DIODE.
Once we have the solder and connection loose from the diode itís time to determine which of the two diodes is the red one. I use the diode tester feature on virtually every multimeter I have ever seen. It is an arrow with a line at the end. This tells us three things. 1. what wavelength the diode is 2. if the diode is still functioning and 3. which of the pins is negative and which is positive. I use a red sharpie to mark the positive and a black to mark the negative. You will find which of the diodes is the IR diode and which is the red one. I toss the IR diode, however you can keep it and do whatever you want with it. The power generally on the IR diode is usually very small but still enough to burn your eyes if collimated.
Once we have found which is red, we take our Aixiz module and pull it completely apart. Removing the lens and spring found inside and unscrewing the two halves. In the smaller of the two pieces you will find a small hole on the opposite side of the lens threads. This is where our newly harvested diode is going to go. Place a small amount of thermal grease inside this hole and place the diode in the hole. Grab a nut driver that is going to have a large enough hole to fit the pins on the back of the diode inside the driver yet still rest on the diameter of the diode. Drive it in with a smack from something hard like a hammer but not very hard. We are trying to drive this in not destroy it. Make sure you keep the diode centered and drive it in completely parallel with the module. You should not, once you have it in place, have one side sticking out more than another. You want this completely centered in the hole. If it is sideways in the hole the light from the diode is not going to center on the lens. Using a Q-tip remove any thermal grease that has gotten on the diodeís window, you may need to use alcohol and if you do, make sure you use alcohol that is 90% or above. Remove ALL the thermal grease. Leaving behind grease is going to impact the effectiveness of our laser. Before replacing the lens I usually take a exacto knife to the opposite end of the optics. You will notice it is a very small diameter hole and we are going to cut very carefully to make the hole bigger. This allows more light to get to the lens and not be reflected back into the chamber. You can now replace the spring and lens into the module and test to make sure you still have a functioning diode after the pounding and placing. If you have ruined the diode pound it out from the inside and start over. At this point you should be able to play around a bit by driving it directly from 2 AAA batteries. We donít wanna play too much cause we are not quite finished and you will find that the module warms up pretty quickly.
In this portion of the walkthrough I will refer to 1, 2, or 3. These are the particular flashlights that we are going to use. I will start with 1 and go to the next and so forth.
1. Dorcy mini. You can get this badboy at Target for under $20. The first thing we are going to do is unscrew the head. With the head off, you can see a small spring sticking out of the bottom of the head. Grab ahold and gently pull this out. The entire thing will come right out.
The reflector and led are held in place by two black rings. Remove both of those rings paying attention to how it is mounted in place. You do not need the reflector, so place it in your save file for later. Unsolder the diode off the mounting plate and using a pair of pliers pry the diode off the plate. If you do this right you can salvage the led. It is not going to be used for anything we are doing so set it off in your save pile. Using a file remove all traces of solder from the plate with the exception of the two contacts that are soldered. One a white wire coming from below, the other is grounded to another metal piece. Those are your positive and negative connections. We are going to clean those up and make sure they are low profile but not totally de-solder them. Once you have removed the solder from the other connections we are now going to isolate those contacts from the positive and negative. Using a sharp implement, preferably a knife, cut into the board on the small lines under the black covering leading from the negative and positive. Sever the connection completely. Make sure you are not getting juice to the other 4 points by using a multi-meter. If youíre not getting voltage to those points any more then we are good. Grab the Aixiz module. Unscrew the lower half of the module and grab a pipe cutter. Using the pipe cutter we are going to cut off all but what we need to bring the focus ring to the end of our flashlight head. In my case it was 9mm of the barrel remaining, the rest was cut off. So my entire module top and bottom is 16mm. Using a dremel tool I notch the bottom of the now tubed bottom so that I have a place for my two leads to come out of. I then take a cut the leads off of a normal led about ĺ inch long for soldering onto the pins of our Laser diode. I solder the leads of the led onto the pins from the laser diode and replace the hollow cap back onto the bottom of the module. I with a pair of pliers bend the diodeís new pins so that they are exiting sideways out of the grooves that we cut into the bottom of the barrel on the module. Making sure that they do not come into contact with the side of the module we then solder the diodeís new pins onto the negative and positive places we cleaned up. Make sure also that the positive connection on the board itself does not come into contact with the module either and epoxy it in place with some thermal epoxy. Power the diode up again one more time to make sure we have electrical connection.
Replace the black rings onto the board to hold everything together once the epoxy has dried and use the built in circuitry below on the battery holder of the flashlight to power it. Slide everything back together once itís been assembled and everything should power up. If you have not got power to the diode then somewhere you have a short. Most likely in one of two places 1. the barrel of the Aixiz module is grounding to the positive or 2. You have the pins from the diode grounding to the Aixiz module.
Take a us nickel and cut a small section of thin plastic of your choice the same size or a bit smaller. This is going to be placed in the top portion of the head of the flashlight for aesthetic purposes. Find the exact center and cut a hole for the focus ring to exit through and you have a finished product.
Now no walkthrough would be complete without video's. links to teh video's are here
By kenkassdy at 2007-06-13