[Ronja] Further lcd thoughs...

[Gyurkó Martin]

I have some experience in the dvd and cd industry. I worked for Datarius 
for 3 years.

First you need to figure out, which connections of the pickuphead (PUH) 
are the photodiode pins and the LD pins. Also the area of those 
photodiodes is so small, that it is almost impossible to reasonably 
collect ligth with these built in diodes. Manufactureres never give out 
specifications. I hate them already.

I also were thinking of using the complete PUH tx and rx without even 
disassembling the optics. CD and DVD uses polarization shift for being 
able to send and receive coaxially. This means, the rx is 90 degrees 
turned respective to tx. If 2 identical PUH are used, and are 90 degrees 
turned, they should even be able to work in full duplex, because of the 
  orthogonal polarization. Also the voice-coil lens of the PUH is able 
to compensate for scintillation in the air.
This whole thing would make a PHD thesis. Especially the compensation thing.
Maybe I someday do it when I have time.

The MLT-3 of the 100Mbit ethernet could be almost directly used. You 
need linear amplification for the LD tx and the rx. Some optical power 
regulation in the TX too, thats all. Maybe the autonegotiation spikes 
must be suppressed to avoid damages of the LD.
The Idle signal is always transmitted in a scrambled form, so you are 
always syncronized.

But for the record:
Use red light! not IR!
"Never stare into the laser with your remaining good eye..."
IR os no fun, you hardly see where it goes.

Bye,
Martin


ronjalist írta:
> RX - old 52x cdrom drive ?
> 
> Given that hacking the firmware of cd / dvd drives is common place (al 
> la xbox360) is this not a possible source for an rx ?
> 
> J.D. Bakker wrote:
>> At 23:25 +0100 07-09-2008, ronjalist wrote:
>>> A vga port for example can be used (depending on video card support) to
>>> generate a hdtv signal - if it can do that I suspect that it may be an
>>> outbound route - now need and inbound .....
>> Unfortunately the transmitter isn't the hard bit (apart from 
>> modulating a light source fast enough, but even that's comparatively 
>> simple).
>>
>> JDB.
>