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CD-Rom Laser module

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Ken M.

Sat Jun 14 2008, 10:13PM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

I had an old Sanyo 52x cd-rom laying around which didn't operate correctly, and so I thought I'd dissassemle it and try and see if the laser module was anygood and use it as a laser pointer of sorts, only problem is it has a 17 pin ribbon cable and I have yet to find a data sheet online, and so I was wondering if anyone would have any ideas on how to find the Diodes power pins and wehat I should use to try and power it?

Hon1nbo

Sat Jun 14 2008, 10:45PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

try to remove the actual laser, as the rest of the pins are optics and the motor... it should be mounted on the side...

...

Sun Jun 15 2008, 01:25AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Try to look for the gold color 5.6mm diameter circle pressed into the side, with 3 pins sticking out. That is the laser module, the two large traces on the flex pcb going to that are the diode power.

Dr. Dark Current

Sun Jun 15 2008, 06:48AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

I don't want to dissapoint you but I think CD-rom laser will not do anything useful.

Bjørn

Sun Jun 15 2008, 01:40PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

A CD-ROM laser is infrared and will not be usuable for laser pointers. It will be visible to the human eye since it has some sensitivity in the IR but the sensitivity is so low that you will go blind before the laser is bright enough to be interesting.

Timo

Sun Jun 15 2008, 01:43PM

Registered Member #1538 Joined: Thu Jun 12 2008, 07:28PM
Location: Bonn, Germany
Posts: 28

I have to agree with Dr. Monsterarc, unless you are looking for an infrared laser.

If you need a visible on, you could try to get a DVD-Drive. They use red laser diodes.

quicksilver

Sun Jun 15 2008, 02:06PM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

SOME DVD writers may point but if you want a fun one get an old laser printer. The old Panasonic 5xxx series has a really nice one that may even be a 30mw, as it's a big one for what it's used for. But getting the specss is another matter (see past posts of mine).

The DVD writers have SMD connections and many micro sized ribbons, etc....Tough to get up and running unless you have "young" strong eyes. The laser printers have a whole wonderful system. (laser diodes w/ associated boards & even though they also used SMD materials you can follow the traces)

uzzors2k

Sun Jun 15 2008, 06:32PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

I found the polarity by measuring the voltage across the pins while exposing the diode to light. The power diode will produce the most voltage near a bright source of light, I was able to bring mine up to 700mV. The can is obviously grounded, which leaves two other pins, one of which may be a N.C.

Polarity from Sam's laser faq

After having played with several CD and CD/RW diodes, I believe that it is possible to determine the pinout to a high degree of confidence without applying any significant power to the laser diode.

All that is needed is a voltmeter (rather a millivoltmeter) and an operating incandescent lamp (tungsten filament like a pocket flashlight). If you direct a light beam to the device under test and measure the voltage between common and each of the other two pins you will find two of the four following possibilities:

About +500 mV. This is a PD anode.
About -500 mV. This is a PD cathode.
About +5 mV. This is a LD anode.
About -5 mV. This is a LD cathode.

The large difference is due to the fact that the photodiode is a much more efficient converter of light to electricity although both the PD and LD work as photo cells. The above figures depend on the intensity of the light but there will be no mistake: The PD voltage will always be much larger that the LD voltage.

For powering I made a rather reliable constant current source. Unfortunately due to relying on the forward drop of an LED the regulated current isn't exactly voltage independent. But if run from a constant voltage source such as an ATX PSU the current regulation will be excellent. Remember to run it with a current meter at all times, these diodes are quite sensitive. If you want it to last only take it 10mA or so past the lasing point. I took mine up 50mA, which eventually killed it.

1213554724 95 FT47420 Constant Current Source

Backyard Skunkworks

Sun Jun 15 2008, 11:39PM

Registered Member #1262 Joined: Fri Jan 25 2008, 05:22AM
Location: Maryland, USA
Posts: 451

Funny this topic should come up, I just found a DVD player with a circuit board cracked in half the other day. I got the diode out by first hacksawing through the plastic housing on the drive, then using a jewler's screwdriver to get the carrage out and then dissolving the glue holding the diode in with acetone.

The diode itself was connected to a small PCB with a four pin ribbon, I can't tell anything by looking at the PCB. Does Sam's polarity method work alright with DVD lasers? (I'd think it would, just wanna check)

What voltage/current do DVD lasers normally need?

Is it alright to drive them off NiMH batteries with current limiting resistors, or do I need to get fancy? (I don't care about great preformance, just some strong red light and not killing the thing)

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