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PostPosted: Sun Apr 07, 2013 4:17 pm
by Harry Dalek
Well i did some tests last night the new paint is finer than the other glow paint i used this seems more like a vanish the old is like a fine powder .

The new one is a better glow paint for discharging as well in the photo middle and drum on the machine are painted with the new paint far right the old i used in the picture tests past posts...you can just see the light dot on that one fading ,the other 2 are still going strong..

Has its good points and bad i suppose easier to charge up with lower laser levels and longer scan times the bad is might still be glowing for the next image but doing the tests i found its still ok just have to reset the levels for this drum.

The Drum has a Gray look to it i have used the purple undercoat drum for these tests below .

Its better for room light i couldn't adjust it spot on yet as i haven't replaced that 100k pot over the diode in Steves circuit yet and it seems its an adjustment i need its so tight at the moment something i will replace today with a 1meg pot
.
youtu.be/JEmc7Jbq7L0

PostPosted: Mon Apr 08, 2013 5:22 pm
by AncientBrit
Harry,

Thanks for trying out the CRT idea.

"Nothing ventured" etc,

I'm surprised about the fluoro. though.
My understanding was that fluorescent tubes produced UV and the phosphor converted it to the visible spectrum, albeit just a few specific wavelengths.

Cheers,

Graham

PostPosted: Mon Apr 08, 2013 5:48 pm
by Harry Dalek
AncientBrit wrote:Harry,

Thanks for trying out the CRT idea.

"Nothing ventured" etc,


Yes never know it might still work but perhaps at higher laser levels or we picked the wrong colour lasers

I'm surprised about the fluoro. though.
My understanding was that fluorescent tubes produced UV and the phosphor converted it to the visible spectrum, albeit just a few specific wavelengths.

Cheers,

Graham


I will double check Graham this as i could be wrong about it silly not to make sure so another experiment coming up ! Why is it so or can it be so :idea: :?: :idea:

PostPosted: Mon Apr 08, 2013 7:56 pm
by Harry Dalek
Hi Graham
Heres uv test with a fluro tube uv light..... it looks like it is uv sensitive but must have to fast a phosphor no good for my SSTV project .. :wink:

PostPosted: Mon Apr 08, 2013 10:55 pm
by AncientBrit
Thanks for trying Harry,

Graham

Re: Mechanical SSTV Steps

PostPosted: Thu Feb 23, 2017 5:42 pm
by Harry Dalek
Some times as i build i take images i don't use ....looking at what i have on file i was thinking of sharing what i have for any one interested .
Now this build had to evolve from a basic idea and to a few dud designs and a lot of trial and error a lot of advice l
So what i will do is as i find images videos i will add them to each post below ......and any thing i recall about them .

Re: Mechanical SSTV Steps

PostPosted: Thu Feb 23, 2017 7:07 pm
by Harry Dalek
2017 its altogether the Glow drum is loose and power supply disconnected been in storage in a box plastic wrapped so at least clean .
The Australian summers are never good for things hot glued ..
I got it out today to have a look i had forgotten at what state i had left it ,its better than last time, i would in time once the CRT monitor is running give it a run together .

Re: Mechanical SSTV Steps

PostPosted: Thu Feb 23, 2017 7:42 pm
by Harry Dalek
Back in may 2011 i dropped the rotating glow drum idea for a rotating drum with 4 evenly spaced holes for the horizontal scan and a moving small glow paint screen ..even with a bank of leds there was a lot of wasted light ,
The screen had to also be very close to the rotating drum to keep the raster dot in focus ....various ideas tried never was happy with this one not as pretty as my drum !

Re: Mechanical SSTV Steps

PostPosted: Thu Feb 23, 2017 8:29 pm
by Harry Dalek
April 2011 another early design change it more than likely would of worked if i had used a uv laser instead of trying to focus one uv led .
Fixed screen rotating 2 sided mirror uv led vertical scanning down the mirror ...mirror uv led reflection drawing the raster on the fixed glow paint screen
So raster to dim ...another off to the scrap heap

Re: Mechanical SSTV Steps

PostPosted: Fri Feb 24, 2017 12:46 pm
by Harry Dalek
I have much more documented on the Drum tests that worked and ones that didn't construction and such..
I found some photos from 2013 it was the second go at the monitor ,i hadn't boxed it nice as i do now so it was a bit of mess heres what i documented as the rebuild .
So for a start kept this drum for a while with the original glow paint just for testing ...the paint i later found out was very grainy not the best choice for a SSTV screen the makers had no Consideration :? Only by luck i found the other brand of glow paint i could buy was very fine and spot on for fine detail needed /
As you see in the animated gif last photo unless every thing is lines up correct scan is a bit wonky

Re: Mechanical SSTV Steps

PostPosted: Fri Feb 24, 2017 7:16 pm
by Harry Dalek
More on the rebuild 2013 and testing ..
My mind was on syncing the horizontal scan line so the hall effect sensor and tiny magnets on the polygon mirror ..i think i found tiny variations using this to sync my clock caused it to run a bit ruff ...i would try an opto switch with the edge of the poylgon mirror points switching the light beam that worked well on an nbtv polygon mirror i tried .

Re: Mechanical SSTV Steps

PostPosted: Fri Feb 24, 2017 10:16 pm
by Harry Dalek
Tracking down some images i may not of used here in this post ///As i mentioned i had experimented with different glow paint these pictures were made on the drum paint in the cheaper glow in the dark paint where as the white knight is a much better product for this ..i also tried a glow in the paint power had a much longer after glow found not at the time but later it was best to mix it with white paint and the effect was interesting as without the paint it glows orange whith the paint green as with these spray can products

Re: Mechanical SSTV Steps

PostPosted: Fri Feb 24, 2017 10:32 pm
by Harry Dalek
More photos taken of drum laser modulation using white knight glow paint not the of greatest shots some out of sync and and taken as afterglow fading /

Re: Mechanical SSTV Steps

PostPosted: Sun Feb 26, 2017 9:33 pm
by Harry Dalek
These are the original first pictures i got with the first drum after the rebuild in 2013 .
I was running it first at half speed so 2 images side by side and few pictures touch out of sync ..
I never did have automatic sync control it was all manual control which was easy enough , the glow drum and polygon mirror were both on stepper motors .

Re: Mechanical SSTV Steps

PostPosted: Mon Feb 27, 2017 7:06 pm
by Harry Dalek
MY original idea was a cork screw scan but thinking about it i would not be able to view the frame until i stopped the drum and by then you would get fading 2011..


youtu.be/2vdYgvSPwI4

youtu.be/gSsvNWeLpvE