Jeffree cell

[Harry Dalek]

I tried with course lapping paste, works well and cuts at a reasonable rate.

Hi John that sounds good i hope it works out .
Heres some stuff i have tracked down which again more than likely is of interest to us all.

[johnrpm]

I am now trying to digest the excellent images you posted earlier, especialy the beam coverter, something else to try and build, although its just my opinion, the scophony system was the ultmate in mechanical tv.

thanks again for posting the information.

[gary]

Hi Harry, thanks for those uploads.

I was just wondering if that is the best quality available for Screen 00001.jpg?

Some of the maths is not really legible.

[Harry Dalek]

Hi Harry, thanks for those uploads.

I was just wondering if that is the best quality available for Screen 00001.jpg?

Some of the maths is not really legible.

Hi Gary
That was a grab out of a google book i have not come across it again sorry..
heres some things similar eithier using crystals or transducers.

The last one is a bit off topic for this post but it shows a lot of different mirror polygon scanning ways which really interests me .

below is link to a magazine bit on scophony

http://books.google.com.au/books?id=iyQ ... ve&f=false

[Don Tomkins]

Gary,
The diagram is actually in the article on scanners which Harry posted.

Don

[gary]

Thanks for that Don, well spotted!

[johnrpm]

The last one is a bit off topic for this post but it shows a lot of different mirror polygon scanning ways which really interests me .

Me to Harry, I have extracted a polygon scanner from a laser printer, it has a brushless DC motor, I have it running with help from the tinternet for the scophony system I hope to build one day, I can post some info on getting it to run if you wish.

[Harry Dalek]

The last one is a bit off topic for this post but it shows a lot of different mirror polygon scanning ways which really interests me .

Me to Harry, I have extracted a polygon scanner from a laser printer, it has a brushless DC motor, I have it running with help from the tinternet for the scophony system I hope to build one day, I can post some info on getting it to run if you wish.

Hi john
Thats a good start Yes any new info is good for me every thing helps ...
I was just at my local dump shed today and looking at an old laser printer
but last one i got jujst had a long flat mirror not a ploygon which was disapointing ..
Have also had a go at something i was telling you about making a polygon from a nut ..i used a large plastic one ...and cut some plastic mirrors ,it has backing sticky stuff so that was ok ...but really need a stable platform to work on one wobble and the next line is another line ! need to try on a HD platter or vcr head.
I have just been reading these posts of a guy in new zealand trying to do a 625 line scanner 10 years ago a lot of nbtv talk in the posts well worth the read ! interesting what i think is a Am laser modulator .
Think DrZarkovs find and posting below should not be forgotten for any one thinking of a polygon television system..
http://www.taswegian.com/NBTV/forum/vie ... highlight=
http://www.diyaudio.com/forums/diy-proj ... ector.html

[johnrpm]

I extracted it from a kyocera, also got one from an old HP, some laser printers do have a led array, but the older ones seem to have the polygon,

the thing you are looking for is like the image attached, and has the lenses
and mirror, the one from the kyocera need a pulse input to regulate the speed, which I think is very stable, it also has a photocell to detect the end of each sweep, which makes it useful for our purposes.

I will take some images and post them.

[Harry Dalek]

I extracted it from a kyocera, also got one from an old HP, some laser printers do have a led array, but the older ones seem to have the polygon,

the thing you are looking for is like the image attached, and has the lenses
and mirror, the one from the kyocera need a pulse input to regulate the speed, which I think is very stable, it also has a photocell to detect the end of each sweep, which makes it useful for our purposes.

I will take some images and post them.

Hi john

Yes thats what my only one looked like but did cut bits of plastic housing away for project testing fitting .
It was a hp laser jet i was looking at but i wasn't sure the one i got mine from was twice the size ..a lot of plastic to get rid of if the polygon is not in there ..
I will take note on your 2nd printer if i come across it ..cheapest new polygon on the net i have found is in the $30's then its up ! thats the only trouble with junk ones the amount of rubbish to get rid of . .but they are cheap 5 dollars .
Here's a quick test home made one with plastic mirrors still a bit of wobble to them ..they are flat on th e plastic nut i can only think the centre is just a bit off and thats a killer it would work but raster line would have a slight jump...still good for testing stuff .

[johnrpm]

Harry,
Yes the mirror faces have to be very accurate, have you considered polishing a hex nut, they are surprisingly accurate, an M10 nut should be big enough, I have done some more dad videos, one for the crystal cutter and one for the bldc polygon being powered, both done on a phone so very poor.

<iframe></iframe><p><a href="http://vimeo.com/28755247">Cutting Quartz crystal</a> from <a href="http://vimeo.com/johnrpm">johnrpm</a> on <a href="http://vimeo.com">Vimeo</a>.</p>



<iframe></iframe><p><a href="http://vimeo.com/28755183">BLDC motor</a> from <a href="http://vimeo.com/johnrpm">johnrpm</a> on <a href="http://vimeo.com">Vimeo</a>.</p>

[gary]

Here's one I made on my CNC machine - I haven't had time to use it in anger yet, or mount it on a proper spindle, but the approach *seems* sound enough. The mirrors are rear silvered glass.

[johnrpm]

I think that with a hexagon and 32 lines 4000 rpm is the speed of the fast scanner, or 3000 with an octagon for NBTV, (my maths may be wrong) but for a bigger picture the speed may get high enough where balance etc may be critical, in one of the pdf's Harry posted, scophony had their's at over 30,000 rpm, and had more facets.

Some time ago I managed to cobble together a very crude laser projector using string and sticky tape, just to see if I could do it, I used a pc speaker amplifier for the laser modulation, a laser polygon for the fast axis and a dc motor with mirrors glued on for the slow axis, after a lot of messing about for 4 nights, for a fraction of a second I got sync and the image appeared,
It really was crude but very satisfying, I always intended to do it properly one day.

[Harry Dalek]

Here's one I made on my CNC machine - I haven't had time to use it in anger yet, or mount it on a proper spindle, but the approach *seems* sound enough. The mirrors are rear silvered glass.

Hi Gary Looking good the polygon mirrors look well balanced ,i am using a plastic nut as a template for the mirrors but i still need to centre it correctly as you can see it in line jumping as i am doing your same laser pen experiment to test it .
Yes i like your polygon !

[Harry Dalek]

I think that with a hexagon and 32 lines 4000 rpm is the speed of the fast scanner, or 3000 with an octagon for NBTV, (my maths may be wrong) but for a bigger picture the speed may get high enough where balance etc may be critical, in one of the pdf's Harry posted, scophony had their's at over 30,000 rpm, and had more facets.

Some time ago I managed to cobble together a very crude laser projector using string and sticky tape, just to see if I could do it, I used a pc speaker amplifier for the laser modulation, a laser polygon for the fast axis and a dc motor with mirrors glued on for the slow axis, after a lot of messing about for 4 nights, for a fraction of a second I got sync and the image appeared,
It really was crude but very satisfying, I always intended to do it properly one day.

Hi John i used google translate on that german guys 625 line polygon monitor the 12 sided large polygon is the vertical and the laser printer thin polygon is the horizontal in he's system amazing he got he's going .
Hes would sort of be scophony without the light cell and perhaps no interlacing.
Did you try NBTV or 625 line john ? + how did you do the speaker modulation i have read about it in one old newsletter but never went into how it was done .
Sounds very interesting wish you could of posted the project !
I saw the polygon and crystal cutting is the polygon motor like a stepper motor i could not see your sheet clear i am got a reverse engineering
Yes well worth another go not enough people using mirrors.