[HH] Burn custom art on a DVD

Tue May 13 07:59:55 EDT 2014

You got my curiosity, so I looked up lightscribe.

http://en.wikipedia.org/wiki/LightScribe

Couple of points:

First: "The center of every LightScribe disc has a unique code that allows
the drive to know the precise rotational position of the disc. This, in
combination with the drive hardware, allows it to know the precise
position from the center outwards, and the disc can be labeled while
spinning at high speed using these references."

So, it looks like lightscribe has an "index hole".
I have no idea how this ties in with the asic controller.
A second laser/pickup maybe? This is hardware that didn't
exist in drives that I worked on.

Secondly: "A LightScribe optical drive was used by Maher El-Kady, a
graduate student at UCLA in 2012 to successfully turn a specially prepared
graphite oxide layer coated onto a DVD into graphene.[8] El-Kady and
Richard Kaner, his lab professor, used an unmodified LightScribe drive."

Holy cow. Might be worth trying to contact these guys and see if their
software is available.

Thirdly: "Companies such as HP, Samsung, LaCie and LiteOn have
discontinued or are phasing out LightScribe drives as of June 2013"

If your son-in-law's boss gets this working, sounds like they might
want to stock up on a few spare drives and a large stack of blank
discs if they want to use this long term.

> Thanks guys I'll report back to him.
>
> On 05/12/2014 02:28 PM, Greg London wrote:
>> I did asic design on CD and DVD burners for a number of years
>> but it was years ago and before lightscribe was an option,
>> so I can't really compare burning data to a disc to lightscribe.
>>
>> I don't know as much about the physical process
>> but I don't know what is meant by "test grooves". My understanding
>> is that burning a cd doesn't actually put grooves on it like
>> a vinyl record but rather turns the transparent polycarbonate
>> dark so that it does not reflect light from the aluminum disk
>> underneath.
>>
>> So that would be the first issue/question, whether the physical
>> process will actually do what they want to do.
>>
>> The second question is one of synchronization between the
>> laser and the spinning disk. I worked on the CD read section
>> of the chip, taking a stream of high speed data, de-interleaving
>> it and running it through a 10b8 error recovery block, so
>> I'm not as familiar with DVD's as CD's but I'm not sure that
>> there is any sort of "index hole" marker on the CD to physically
>> align the head back to the same spot.  audio CD's are one big,
>> long spiral of data starting from the inside and working out.
>> DVD tracks are concentric circles with sectors and whatnot.
>> But  I don't know of there is any kind of index hole so that you
>> could put down a stream of 1's on one track, move the head out,
>> and then put another stream right alongside the previous stream.
>>
>> If the only requirement is to create a specific pattern
>> on a single track, it should be possible. But if you
>> want to lay down data on different tracks and have them
>> be physically aligned with each other, I'm not sure
>> that's even possible.
>>
>> The other bit of weirdness is that the RPM changes as you move
>> the head to different tracks. The goal is to achieve constant
>> linear speed over the track which gives you constant data
>> rates coming off the head.
>>
>> Back in the day, audio CD drives were built with only very
>> small data buffers in silicon, usually just enough to perform
>> de-interleaving, 10b8 error correction on one block (48 bytes)
>> while receiving the next block. So, as the head spiraled further
>> out from the center, the disk would be spun at slower and slower
>> rpm's.
>>
>> I think DVD's generally follow this Constant Linear Velocity
>> approach, which means you've got more data in a track as you
>> move further out from the center. This doesn't make it impossible
>> but if you want a couple of "test grooves" to lay side by side
>> then they'll default to being the same linear length, not the
>> same arc of rotation.
>>
>> Lastly, based on how our chips worked, I can't even imagine
>> getting direct control of the heads through software.
>> Maybe other chips let you have more direct control, but
>> there is so much data flying that most of it is automatic.
>>
>> By the time the serial data comes off the disc, its already
>> run through serial de-interleaving, 10b8 error correction,
>> and a bunch of other hardware blocks before the software
>> ever sees it. prior to that point, its just moving too fast
>> for software to keep up.
>>
>> I think the best you could hope for is to work within the
>> existing DVD format and simply try to control what track
>> the head is on and then give it a block of data to write.
>>
>> And even then I don't think there is any way to align one
>> track to the track next to it.
>>
>> Anyway, this is all very fuzzy recollections of stuff
>> I worked on a long, long time ago, in a galaxy far away.
>>
>> Someone more current might be able to do it no problem.
>>
>> Greg
>>
>>
>>
>>
>>
>>
>>> My son-in-law got this from his boss. I assume he wants to burn art
>>> into a
>>> lightscribe DVD. The place of business is in East Cambridge, his wife
>>> used
>>> to live 2 doors away from me while she was married to someone else.
>>>
>>> -------
>>> The objective is to burn many grooves on the DVD that will NOT be
>>> holding
>>> any data or pictures.  Imagine that you have a pattern template that
>>> you
>>> have drawn using some drawing tool and you want to burn  "grooves" on
>>> the
>>> DVD using the DVD writing head.  There are "artist" specific software
>>> that
>>> do this however, they are not precise enough for my friend's purposes
>>> which is to create "test grooves" to test various organic compounds
>>> using
>>> low voltage electricity.
>>>
>>> So I guess what I am looking for is someone that can write a firm ware
>>> to
>>> move the head AND provide a "crude" user interface to draw simple
>>> straight
>>> lines (for the template) and use the DVD writer to etch the grooves
>>> along
>>> the lines created by the user.
>>>
>>> Here is the device:  HP CDDVDW TS-L633N 0300 195 (LightScribe)
>>>
>>> They will pay good money for an electrical engineer that can do that.
>>>
>>> I hope this is helpful.  This will not be used in any commercial
>>> capacity.
>>>  It is only for testing in a laboratory environment.  Thanks.
>>> -------
>>>
>>> --
>>> Jerry Feldman <gaf at blu.org>
>>> Boston Linux and Unix
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>>>
>>>
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>>
>
> --
> Jerry Feldman <gaf at blu.org>
> Boston Linux and Unix
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