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Hello,

I am sorry if this question is not in the right place. I am now in urgent state of having to figure out how to interfere the writing process of a CD-Writer or DVD writer.

As you known, the CD-Writer always write EFM signal onto the CD-data layer.
The question is how to interfere this process by our own signals.

Our job is to write a special Hologram Pattern on the CD surface. That pattern cannot be done by normal burning process of EFM singals. Hence we need to interfere this process.

Some more question:

There are so many things should be considered when we are on the way finding how to solve the problem as mentioned above.

1. How to start the burning process
2. Do we need to control Cd-motor speed, the Pickup Head moto speed or we can let the CD-driver control itself if it possible, how?
3. How to find the starting/ending point of the CD-pregrove spiral
4. ....


Thank you very much in advance ...
With best regards,
T.Q. Hoai

PS: if you have any document pls inform me by hoaitq at icu.ac.kr

Do you intend to use a medium other than a CD?

Hello,

Thank you very much for your response.
I think I would be more clear if you read the paper "Production of computer-generated holograms on recordable compact disk media using a compact disk writer".
Pls download it here:
http://psp.icu.ac.kr/adminUploads/Fi...isk_writer.pdf

In this paper, the authors succeeded to write a hologram pattern on the CD-R by interfere the burning process.

Pls take a glance on the paper and you will understand my question.
I am sorry if it take your time.

Best regards,
T.Q. Hoai

Well I give a stab at the first. To start the burning process tell the drive to write a small image file of data, after the drive does its calibration is when you would interupt that bogus data and insert your EFM signal, via an "analog switch". You can use any burning software like Nero to tell the drive to burn the image file.

So whats this project for? Senior Eng project?

Sorry, the Hologram image cannot be created by EFM signals, It should be done by PWM (pulse with modulation).
That's why the author used the analog switch to switch between EFM and PWM signals.

Because the information in the paper is not clear enough for us to follow.
Now we are trying to find how to trigger the CD-Drive to start its automatic burning process. And we just simply replace the EFM signals by our PWM signals when we want.
Could you pls tell me how to do so?

are there any free source codes or document to guide ?

The aim of this project is for making any hologram patterns on the CD-R surface.

Thank you very much for your kind and quick responses.

I think you would get more help in this forum. Maybe a mod will move it for you > http://club.cdfreaks.com/f52/

Did you try contacting the author? Another person that might not mind answering some questions would be LighteningUK, This is his website.

But without having some advanced knowledge of how the cd burner works, I could only suggest dissasembling the burner and finding which pins are responsible for sending the final data stream to the OPU, then splicing into them to feed the new signal which would be triggered by the calibration signals. To get the drive to start sending the signal it would have to still be connected to a computer and still be capable of burning a normal disc to make sure its still operational after modifying it. You can use any burning software program like Nero or even IMGburn to initialize the burning process.

Did you get diagrams for all the IC's in the ODD?

Sorry, currently I don't have diagrams for all the IC's in the ODD.
I am trying to contact the manufacture and waiting for their response.

I think your suggestion is valuable if we can know the relative position between the Pickup Head and the CD.

In the paper, the author used one optosensor. For my understanding that's sensor is just for checking angle not for cheking radial distance.
Could you pls tell me how?
Thank you very much...