Help Identifying Diode

[Last One Left]

Hey everyone, i got my hands on a few dvd burners and planning on building a red laser, i already have two aixiz 5mw laser and i ordered to driver of ebay..i have a liteon dvd burner..im not sure of the speed of the burner or any thing much..it has DVD+Rewritable R/RW to the back it says manufacted in 2003 and its model LDW-811s, i also says Class B..
Can anyone help me as to what type of laser diode this contains and if its worth using for a burning laser..also how much mA i would have to push it with..

The other burner is liteon DL...
and another a super writemaster speed plus..any advice would be great..

 

[kiyoukan]

Well the rating on the box if i remember means nothing.
Its hard to tell without seeing the exact laser if you pull it out and give a picture we might be able to give you something more.

 

[Last One Left]

Ok kool..i would do that by tmr..
But wont alot of diodes look the same and still be of different mW output? therefore some would use higher mA than others?
Ive spoil about three diodes already lol i want these to work..

 

[kiyoukan]

Well there are a few different shape lasers. that can give us an idea but it its the normal generic style there is no easy way to tell just start low and when it gets to what you want it stop. or if you keep going in power and see no difference then draw it back till it just slightly starts to be less bright.
You would be better off buying a red lasers from one of the stores they have been tested and have know running currents.

 

[Last One Left]

I know buying ready build lasers would be best, but thats no fun lol..Besides im working as an IT Tech right now and i have alot of used dvd burners to play around with that the company disgarded..so i want to try them..by knowing the brand and model of a burner, wouldnt that help distinguish what type of laser diode it would contain?

 

[Morgan]

Hey,

There are likely more than one diode in the drives and identifying which is which is a bit hit and miss. The optics will give you a clue but nothing's gauranteed. The only real way is to do as kiyoukan suggests. Start with low current and work your way up slowly. Unless you know you have Bluray in there then you're going to be starting somewhere around 2.5V @ 20mA and cranking up. The important things to be aware of are heatsinking, (even a low power LD will die without being installed in some sort of module, i.e. an Aixiz), Is your LD IR or red? (If you're not sure if the diode is IR or not then don't view it directly. Use a mobile phone to view it. The CCD sensor will pick up IR light you cannot see. If it's red, it'll be obvious!). Pin configuration, (this will usually be similar if the diodes are red or IR but different if Bluray. Check out the, "Diode Compilation", thread for these.

If you find the IR diode then you can probably get to maybe 200mA but won't be able to see it, (except for a dim, dark red). If you get the red, (depending on the drive), it'll likely be low powered but a nice first successful, visible photon release! Be careful, sometimes diodes contain both IR and red chips but these have 4 pins on the back as opposed to the more usually 3.

Most will give you the advice to swiftly move on from random drives but the experience of harvesting, installation, soldering and powering are invaluable. You will soon be seeking out LOCs, LCCs, PHRs, GGWs and the rest... The testing has been done and the parameters known. They are not all that pricey either to start with.

When you do extract the diode you wish to rescue right now, if it is round and 5.6mm in diameter then you will likely be able to install it in a module and use it. If it's not round and 5.6mm in diameter then you can't, (easily at least).

Incidentally, when kiyoukan said you'd be better off buying a red laser, I'm pretty sure he meant buying the LDs that we all commonly use to build with, not just buying a completed laser. There are plenty of places to get them here on LPF.

Have fun, but safe fun!

M

 

[Last One Left]

Thanks alot for the info Morgan, you really helped me alot..much appreciated!!!
As for the pictures i took them last night with my cell phone so they kinda crappy..i would still post up a couple since kiyoukan asked me too

 

[Morgan]

Yep, that first one definitely looks like our favoured package. 5.6mm at the base, steel coloured, "can", with a window for the emitter... How many connections on the back? If it's three then it only has one die, or chip, in it. If it has four it might be IR and Red in one package.

Is the other photo the same diode before removing it from the heatsink or did you find a couple of LDs in there? As you progress, the heatsinks change but the basic layout of the diodes is similar. Some have no cans, some cans are longer, window size varies... But all the ones we like to use are the same 5.6mm across at the base.

IR and Red diodes most commonly are case negative. I.E. that's where your black wire goes assuming you're obeying convention. This pin can be identified by the lack of a black insulating ring around it's base. One of the other two is obviously the positive contact. This can vary but is likely to follow the common connections in the compilation thread I mentioned. Likely, but not gauranteed!

However you wire it though, if it was free, or dirt cheap, don't stress when you send it on the great diode graveyard in the sky. You'll pop more expensive ones down the line. Cry about those ones, not these.

Obviously, please check out the safety section to be sure you are aware of the dangers and know how to minimise them.

Good luck and post back what you find.

M

 

[Last One Left]

Thanks man, and yes the second picture is before i took it out..i should have place that one on top lol..
The diode is silver at the top and gold at the bottom with three pins, so its just red no IR..
can you point me toward a good driver to test with or should i build one?

 

[Morgan]

It's just red OR IR but not both. It may not seem like this is helpful but at least you know there is only one way to hook up one diode. It still doesn't help with what wavelength you expect as an output but...

A driver you say? The best for starting out, (IMO), is the DDL driver based on the LM317T voltage regulator, (voltage regulator being used as a current regulator!). It just feels right to build it yourself at this stage and is very cheap to buy parts for. Here's a link but there are many, MANY others for this one, (search, "DDL Driver") - http://laserpointerforums.com/f42/diy-homemade-laser-diode-driver-26339.html

As for bought ones... I would stay with a linear driver, (DDLs are linear too, i.e. you have to put in a higher voltage than is actually required by the LD to power the circuit etc), as they are less prone to damage from inexperience and cheaper in the first place. RCKSTR are well known and loved and, unlike the DDL, easily fit into an Aixiz module.

The buck/boost option or just boost option? Has to be a Flexdrive or the new Boostdrives. A boost drive can drive higher voltages than the input so you can run a 5V diode from a 3V battery. Both the mentioned drivers can do this but the boost/buck can also use, for instance, a 5V source to power a 3V diode. This is not possible with the boost only driver. (Does that make sense?)

Both these drivers can be found in the Pro Shop, or B/S/T sections.

Bear in mind that at some point you will need what's called a Dummy Test Load, (You'll come across mention of these in the DDL threads). They simulate the voltage requirements of a diode and allow the output current to set using a DMM set to mV. Setting current by how bright your diode is may work at this early stage with low power, free or at least cheap diodes but you are 100% going to need to accurately set current outputs VERY soon. This piece of equipment should be very near the top of your list. Right under DMM if you don't already have one.

I hope that helps but ask away if you need more.

M

 

[Last One Left]

I think i would build the driver, i already have the parts as i purchased them a while ago..
Can you explain how do i go about using the test load to set my driver mA output? thanks for all your help, really appreciating it..

 

[BShanahan14rulz]

I built the DDL driver as well, to provide power for my red diode. The recommended test load includes diodes in series, along with a single 1-ohm resistor. This resistor is just a way to measure the current easily. Since V=I*R, and R=1, V=I for this resistor. This means, you can measure the voltage across this resistor and then pretend that instead of Volts, you are reading Amps (1000mA=1A)

 

[Last One Left]

Thanks really kool man..thanks alot..can you tell me which diodes need to use and how many? thanks..

 

[BShanahan14rulz]

If I remember correctly, I used 4 1n4004 diodes. the resistor is a little more tricky, it would be good to find a 1/2W 1Ohm, or a 1W 1Ohm resistor, though 1/4W will work in a pinch if it's all you have.

Basically, for whatever laser diode you are using, you want to drop the same amount of voltage using cheap diodes like these 1n4000 series. I think you'd use 3 or 4. I used 4, since the pack I got were 0.7Vf, and I was trying to match 2.6V.

 

[Morgan]

Flamingpyro has some lovely test loads so you might want to drop him a PM.

Good info Bshanahan14rulz! The only thing I'll add is that when you're up to higher power LDs the diodes in a test load get mighty hot so choosing a higher power dissipating resistor at an early stage will reduce the need to upgrade later. The smaller tolerance you can get will also improve measurement resolution. These are more pricey but accuracy is improved.

M