Mechanical SSTV Steps

Forum for discussion of SSTV topics. Slow Scan television (SSTV) is a picture transmission method used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or colour.

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Postby Harry Dalek » Sat Sep 10, 2011 8:36 pm

gary wrote:
harry dalek wrote:Hi Gary
My internet speed has dropped back to ancient times so i will look at the you tube link when i get my speed back ...I have seen a fair few people doing glow paint images but they all seem to be using computer controled servos even the laser modulator is as well.
Thanks for the link i will check it out love seeing other peoples gadgets.


Harry, you are either downloading too many movies or you need a new ISP/plan - where are you? Back O'Bourke? ;-)

(for comparison purposes I am on 500G download - I never get close...)


Its not my internet gary there are 9 people my my house and 7 pcs all using the same net ..no movies for me : ( but i think my sister and brother inlaws do tv shows ..we have 70gig and if its used it go's back to the bad old times yes way back of Bourke is old Doreen ...we still have roos and emus near by .
Poor me :cry:

BTw what are you going to use your polygon in looks very nice playing around lately with them i know they are hard to make right !
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Postby gary » Sat Sep 10, 2011 8:44 pm

harry dalek wrote: ...we still have roos and emus near by .
Poor me :cry:


Me too! (at least in 2 weeks time)
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IMG_20110714_114859(small).jpg
IMG_20110714_114859(small).jpg (145.79 KiB) Viewed 7892 times
Perfecting an NBTV system is like trying to slam a revolving door...
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Postby gary » Sat Sep 10, 2011 8:46 pm

harry dalek wrote:BTw what are you going to use your polygon in looks very nice playing around lately with them i know they are hard to make right !


I was thinking of using it for a flying spot camera, but I am now getting promising results with a bead disk. We'll see...
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Postby Harry Dalek » Fri Mar 01, 2013 10:43 pm

Well its been a while since i worked on this one ....i wanted to get back to it for some time so i will post up what i get up to with it .

I Wanted indoor night project to work while the CNC is the shed day project work.

Getting it back out of its case the test drum was in poor shape the others were still good so i know what will last my hot summers .

Did a quick fix of the test glow drum but testing the stepper motor the driver its playing up so i made another version of the stepper drive using a 555 4013 and L293.

I wanted to see if the polygon motor would fire up that seems its dead more than likely why the laser printer i got it from was dumped.
i didn't want to use a DC as last time with motor drift ,so trying the mirror on another stepper it should be able to do the 16hz horizontal .

I also had trouble with uv laser modulation...as i recall.

I will look again at my NBTV version of this and see if i can use any ideas to use on this ..the laser modulation for the uv laser needs to be looked at again ...i should do schematics and i will try this time as i tend to forget how i did it .

I have pulled it to bits to test again and do some other parts of it a different way.
Attachments
P1040764.JPG
The old drum was in a poor state
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P1040765.JPG
i want to try this motor with the polygon mirror
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P1040772.JPG
remounted the drum
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P1040777.JPG
Heres the schematic of the stepper motor driver sorry about the messy drawing
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Thu Mar 07, 2013 7:31 pm

Tonights first night in a while i could tinker on this again .
My plans this time are to a get pulse from the start of each line via magnets on the polygon and hall effect sensor ,each line pulse should drive the large drum a line so it has to keep pace with the 6 polygons sides.

Syncing the polygons stepper motor is a little up in the air and some one may be able to tell me if this idea is going in the right direction .

I would like to just use the sstv horizontal sync and the pulses from the hall effect sensor feed them to either a bistable or PLL as in the NBTV way ..

The trouble is the frequencies will be off can you sync 2 different frequency pulses....mmmmm

Must read more as i recall they used to use the line frequencies to sync the monitors but this would be a problem with 50hz country trying to sync a 60 hz countries sstv .

Reading the past mechanical hard copy versions on this thread and trying to work out mines since i am using a polygon 6 times per rotation to their one .

One rotation on that past system the motor had to run at 900rpm 15hz
15hz times 8sec 120 lines

Now if i have got it right mine would run slower much slower due to the 6 sided mirror per rotation dividing the 15hz horizontal pulse by 6 i get 2.5 hz 150rpm .
Attachments
P1040884.JPG
Magnets i am using
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P1040886.JPG
mounted my magnets on the polygon
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P1040888.JPG
motor test run
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Postby Harry Dalek » Sat Mar 09, 2013 11:50 pm

Today i rebuilt the SSTV circuit and laser PWM this pretty much worked for the laser tv project so little changes needed to tack it on to the sstv part .

Also started testing the hall effect mechanical clock see if it would drive my stepper motor from what i can see it might have promise it works but i feel its still a little ruff for a steady motor run as is.

From my testing of the NBTV version i could get a picture with just manual control of the speeds of the 2 motors both stepper types using a 555 clock so this is the same sort of idea so at worst it should not effect getting an image of some sort .

My Uv laser test on this glow drum i pulsed the laser to see is i could get thick lines of black and white bars ,but due to the DC motor used at the time this was not really not possible it would always just drift so i was getting slanted lines it would of been a very wavy picture .

Should be a little easier this time around when i do laser testing.
Attachments
P1040892.avi
slow manual test of the hall effect clock
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P1040895.avi
first hall effect test driving the other stepper motor
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P1040893.JPG
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Sun Mar 10, 2013 4:39 pm

Heres the circuit i will be testing out , the laser modulation part is almost the same as the NBTV version apart from dropping the a 741 since the sstv circuit takes that part anyway .

The sstv part works from a test run, the 555 is for the horizontal sync...might be able to use it for the polygon syncing .

i have no brightness or contrast with the nbtv one the pc's volume control took care of one of them this is fm so may make the 1k to the mosfet a pot.

As i recall the voltage to the uv laser was around 4.5volts could of been 4.7 for the nbtv laser they are all a bit different so its best to work with a 5 volts to a resistor wheel starting around 3 volts and drop the resistance one at a time till it lights then do a voltage reading and i should of said do one at the start one voltage mistake and its dead .

So i will be careful testing this part of it .

PS theres a mistake in the PWM circuit see future posting to redrawn cschematic and add ons
Attachments
sstvlasertestcircuit.JPG
my test circuit
sstvlasertestcircuit.JPG (160.55 KiB) Viewed 7829 times
Last edited by Harry Dalek on Fri Apr 05, 2013 8:46 am, edited 1 time in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Thu Mar 14, 2013 9:59 pm

Today i made a new Glow drum mounted another UV laser i had.... and syncing the polygon faces via the hall effect sensor lm311 to pin 5 of the 555 timer glow drum stepper motor clock ,it sync's as well to pin 6 of that circuit both via a 1uf cap but using pin 5.

I need to reverse the glow drum stepper motor direction ,i still have not got to try the SSTV board on the laser .

I might have to change the uv laser back i can't get into the case to see if its just a laser diode or has protection circuit of some sort so i will find out .

This ones pretty strong when running full ball very bright running at the moment in the pictures just enough to test with .
Attachments
P1040917.JPG
new glow drum new laser
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P1040920.JPG
painting some raster lines
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P1040921.JPG
nice close up of the lines
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P1040919.avi
test run
(6.12 MiB) Downloaded 211 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Tue Mar 19, 2013 8:21 pm

I did some full tests last night with the laser i showed in the last post and in these pictures + video......
AVi was first test to see if the laser would modulate with the circuit .It seemed to but as i learned with the NBTV video tests some time back that if the laser used a circuit board it filters out the video even if it looks like its working ,so i had to know and this laser has no use to me unless its modulating video ..as you see it does have one and i will by pass it next test .
Hated cutting it open was i nice looking laser but again no good to me if it doesn't work .

I have swapped the drum around and relocated polygon stepper motor so its rotating the right way ...it was wiping out the raster lines before i could see any thing the other way .
Attachments
P1040929.avi
well looked good but the laser has a circuit connected to the laser filtering out the video signal
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P1040949.JPG
Well i had to know why is it so ; )
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P1040943.JPG
a disappointing first go time to pick my self up and try again
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P1040944.JPG
Just put this one in to show the laser has plenty of power if need be
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Thu Mar 21, 2013 4:00 pm

I am happy to report the Glow paint slow scan mechanical televison works. i am getting 2 pictures side by side so polygon is running at 2 times line speed i expect .

Sorry for the poor picture video today i am very rushed having to go out later so this is the best i can do today .

I had to knock the laser right back and these are taken in room light ..as i said i don't have good control of the video yet .

I ended up using another power supply one for the laser board one for the stepper motors for some reason every time i modulated the laser the motors would change speed .

I am also infact running both in manual at the moment so will not be touching stepper motor speed for a bit ....trying to sync this was HELL NBTV is much easier and i am only half way there ....i am one very happy Harry today .
Attachments
P1040967.JPG
the skull and cross bones i have the first slow scan mechanical pictures of
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P1040974.JPG
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P1040974.mpg
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P1040975.mpg
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Thu Mar 21, 2013 4:25 pm

Well done Harry - congratulations.
Perfecting an NBTV system is like trying to slam a revolving door...
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Postby Harry Dalek » Thu Mar 21, 2013 4:57 pm

gary wrote:Well done Harry - congratulations.



Thanks Gary getting there .....

Those were the first images taken so i hope to improve !

The laser can give a very bright line but i think i need to isolate the written line or the glow drum sees the bright uv.... perhaps some black paper blocking the light from the written lines /

its also inverted so i will swap something around on the lm311 inputs .

knowing its working makes things easier now .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Thu Mar 21, 2013 5:12 pm

Yep - tweaking time....
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Postby AncientBrit » Thu Mar 21, 2013 6:33 pm

Harry,

Your experiments are amazing.

Keep up the good work,

Cheers,

Graham
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Postby Harry Dalek » Thu Mar 21, 2013 10:39 pm

AncientBrit wrote:Harry,

Your experiments are amazing.

Keep up the good work,

Cheers,

Graham



Thanks Graham i am rather fond of the old P7 CRT SSTV when people had to make there own SSTV....
Isn't it nice to know theres a replacement for a CRT and in this case a pricy one too.

Yes too Gary time to tinker i want to see if i can do a p7 replacement showing photos with lots of shades of grey but this is a start just took me a little longer than i expected .

I think it could do 32 sec and longer just need to work out the problem of using higher laser levels without wiping the written raster lines from the laser glow might have to enclose it with just a slit or a mask have to think about that one .

I can also now do some testing on other glow paints powders .

Any case today is a good day for SSTV
Attachments
P1050001.JPG
X test card
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P1040986.JPG
Different skull inverted picture
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P1040989.JPG
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P1040991.JPG
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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