Mini laser cutter from DVD parts

[LurkyTheHatMan]

Hi guys (long time, no post)

After reading all this discussion about buy-vs-build with regards to a new laser cutter for the space, I was inspired to investigate both sides before weighing in (I still haven't decided which side I fall on). After a quick search on google, I came across this little gem: http://www.instructables.com/id/Pocket-laser-engraver/. At its heart is the brilliant idea of using the sleds of two DVD writers, and one of the laser assemblies to make a miniature laser cutter.

After picking up a pair of DVD drives for next to nothing, I set about taking them apart to get at the goodies. It was at this point it struck me that one of the things that ba DVD drive is very good at, is one of the critical functions of any XY machine; namely accurately positioning a laser.

The instructable uses a pair of stepper drivers to control the positioning, but I realised the control board of the drive must already have some form of stepper driver built in. Thus we arrive at the crux of this initial post: trying to figure out if I can hijack the board for my own purposes (and how to go about it). I have been slowly reading up on SATA, and I'm not sure if I can issue position commands over the data cable; I have also tried getting the data sheets for the four largest IC's on the board, but several hours of searching means either the pdfs are not online, or my google-fu sucks. I've attached images of the four IC's (and overlayed the labels on two of them because they didn't quite come out), and I would appreciate help in identifying them. I'm pretty sure the largest one, labelled "Panasonic" is the SATA controller/main board controller (It might also be the stepper controller, but I haven't got the right tools to easily follow the traces).

[Pat McDonald]

Optical drives don't position in X-Y. They just position across a diameter (one axis).

[Mellchie]

But if you use multiple dvd drives...

[Pat McDonald]

712729 is a regulator. 

http://www.alldatasheet.com/datasheet-pdf/pdf/254902/TI/TPS71729DCKTG4.html

MN103SD6FDA is a Matushita custom controller oft found in drives, flash RAM built in so may be reprogrammable (if Matsu will let you know).

http://www.ic50.com/ic/MN103SD6FDA.html   <- Hope your Chinese is good.

AN22023 is a micro power controller.

http://www.datasheetarchive.com/AN22023-datasheet.html

Other one appears to be I/O controller, it's mentioned on this huge great Intel spec but details are vague;-

http://www.datasheetarchive.com/dl/Datasheet-076/DSAE0031331.pdf

[Pat McDonald]

The way I read this set of tea leaves...

712729 gives a rock steady 3.3V supply.

MN103SD6FDA runs the show.

AN22023 powers the laser emitter, or possibly pulses the stepper motor (maybe both).

R2A3-0231-SP takes the received pulses and performs analog to digital conversion.

So it's really just the MN103SD6FDA and AN2023 that are even theoretically usable. Although it is true that you could just recycle the silicon and use the mechanical bits with your own controller... IF you can find a tiny but high powered laser to fit it.

Quite frankly, a helluva lot of work whichever you do it and very small chance of success.

[Greg Milway]

That's pretty much what I was thinking. Thus, a combination of lack of useable datasheets, the proper tools, and little experience of hijacking microcontrollers from proprietary boards suggests that I should go witht eh standard approach of using stepper driver boards, and then building a laser driver from an LM317 when I've got the XY part working.

It was just a nice thought that I could save some money (the stepper boards used in the instructable each cost more than both of the drives I bought), and avoid re-inventing the wheel.

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[bruce]

This is so bloody infuriating: I wrote a long reply , but my Internet connection is pants. It crashed

 and the entire post vanished.

So, to précis: I'm interested in playing with laser diodes. I've got a box full of diodes, mostly IR. But

there are some DVD R/W assemblies which should have a red one. It's the red I'm interested in,

although you might prefer the IR if the beam is more powerful.

 

I did ask if anyone had messed with these things before, but got no joy. Perhaps a laser diode workshop?

 

Bruce