DVD burner in minimag laser..

[stephenmadpotato]

Hello all,
I saw that guide to making a dvd red laser in a maglite and I said "Damn I got to get me one of dem." So, I went to ebay for the parts.
First things first, the housing
http://cgi.ebay.com/650nm-5mW-laser...ryZ53141QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

(sorry for the really long link )

and that kickass laser diode:
http://cgi.ebay.com/Lot-5-140mW-650...ryZ53141QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
(Yes 5 because I will probably destroy about 4 before getting it right. )

and 2 minimags.
http://www.radioshack.com/product/i...&origkw=maglite&support=support&tab=techSpecs

one for me, even though I already have one and one for the project.

If anyone has any better link or anything that may help let me know. I am open to suggestions.

 

[Gazoo]

You will never get it right unless you add some additional circuitry. This has been discussed a zillion times....do not connect a laser diode directly to the batteries.

 

[cdesigns]

I have done it with a LG dvd burner diode, using a CR123A brand new battery. It worked fine 2-3 days of testing until I connect it my 3v powersupply and forgot to lower the current :mecry: and it fried my diode at 500mah

Here is the LG diode burning stuff with the CR123A
http://media.putfile.com/DVD-Laser-mod

 

[stephenmadpotato]

Ok, so heres the plan for the circuit

Anything wrong?

 

[cdesigns]

You need to adjust the CURRENT not the VOLTAGE. the voltage is always going to vary GOOD batts or WEAK Batts

 

[chimo]

Anything wrong?

Yes. The LM317 can be used in a current regulation mode, however, it is a linear regulator and needs a couple of volts of overhead to function properly. That means if your laser diode (LD) voltage will be around 3V at the current you wish to operate it at, you will need another couple of volts more than that from your battery (say ~5V). It will not function as you desire with 2x AA batteries (Alkaline, NiMH, NiCad).

You can search for a voltage regulator with a lower drop-out. I have managed to get about 210mA to a Sony LD from a single li-ion using an MC33269.

Paul

 

[stephenmadpotato]

Yes. The LM317 can be used in a current regulation mode, however, it is a linear regulator and needs a couple of volts of overhead to function properly. That means if your laser diode (LD) voltage will be around 3V at the current you wish to operate it at, you will need another couple of volts more than that from your battery (say ~5V). It will not function as you desire with 2x AA batteries (Alkaline, NiMH, NiCad).

You can search for a voltage regulator with a lower drop-out. I have managed to get about 210mA to a Sony LD from a single li-ion using an MC33269.

Paul

Hey paul,

Thanks for the help. I am thinking of backing it down to a basic resistor then. I never learned ohms law and now this is coming back to bite me right in the ***. I did a little research on wikipedia about ohms law.What specifications do I need on a resistor for this to work? Thanks,
Stephen

 

[Gazoo]

Ohms law is easy if you know how to add subtract multiply and divide. I use the following link:

http://www.the12volt.com/ohm/ohmslaw.asp

Don't forget to put a capacitor across the diode...47uf 16volt is recommended.

 

[stephenmadpotato]

Ohms law is easy if you know how to add subtract multiply and divide. I use the following link:

http://www.the12volt.com/ohm/ohmslaw.asp

Don't forget to put a capacitor across the diode...47uf 16volt is recommended.

That is an AWESOME link thank you very much. I have always wanted to teach myself this but wikipedia's explanation wasn't as precise. Thanks.

 

[Gazoo]

You are welcome. I also send you a PM..

 

[steluta]

SPAMMER removed.
bernhard