SSTV Mechanical video recorder Attempt
 

I am working on phonovision but got to start some where ...i did start by seeing if i could record any thing no matter how bad but got to the point where voice music was ok then i had plans to widen my bandwidth with SSTV which to me is a step i always wanted to do record it on a record ...early 33rpm recordings were very very poor funny enough but in sync i found you really need at least 45 and much better 78 Rpm for this system
Looking into Albert's great work on wax drum NBTV and Jeremy Jago in 2006 NBTV has inspired me...and of cause the Great John logie baird .
I didn't want to use a working turntable wanted to make it from scratch so lots of trial and error and design changes ...This did make it very difficult as i am finding now on syncing the lathe to a standard 78 rpm player ~!:dunce:
This is what you are seeing in the youtube video below the lathe is a bit out speed wise so is the syncing then as shown .
I think due to the problem with a dc geared motor syncing it would be easier to just work on a play back head arm for the lathe and i can adjust things much easier from the same machine without making it standard for now but that my follow in time .
I also had a few go's at designing the lathe cutting or embossing head ended up here so far using a dvd stepper motor wired soldered to a a gem play head of some sort shown below ...
https://www.youtube.com/watch?v=svpDroXEqIQ

Re: SSTV Mechanical video recorder Attempt
 

Brilliant! I wouldn't have thought that much was possible.

Re: SSTV Mechanical video recorder Attempt
 

Didn't RCA have a go at this and ended up going bankrupt? They had all sorts of issues and released a player at the same time as BHS came out, I think. Admire your tenacity, clever stuff.

Andy.

Re: SSTV Mechanical video recorder Attempt
 

Hi Dom long time no see : )

Well the big problem is NBTV Baird dropped the bandwidth with 5 frames a sec 30 line. No syncing 78 RPM

Well i am doing at the moment 78 RPM one frame per 8ec 120 line and i have no syncing either all manual at the moment ...i will post some pic's

I did end up making the play back arm with ceramic cartridge so i am play back the recordings on my lathe and adjust the speed as with no syncing i am am the syncer !

As you see the results are rough but playing back video from scratches on a cd this is pleasing, and gives me hope to go on i want to try other SSTV modes fax so on but i need to sync which is my next step. I went with SSTV as i know it is easier and it gives me a test bed to see what works what doesn't there have been many redesigns !
I hope to do a type of phonovision in time i can see next year being a lot of head scratching ..have to say this is the hardest project i have ever tried.

Re: SSTV Mechanical video recorder Attempt
 

High Andy well it is a dreadful way to record and play back video so i can understand that even Baird gave up and never gave it a go again he was never happy with the results !

Most people make record lathes from old players results good or bad depending on your macgyvering skills video sort of harder due to the bandwidth needed to record this and the syncing/
below my player and recorder same device i just change the play or record arm cartridge the old cd or dvd motor you see on the side i just use for the up and down movement and the magnet it holds the arms they just snap on and off so easy to change for record or play back .i will post up if i get to another step pity i can't upload video here .

Re: SSTV Mechanical video recorder Attempt
 

All you need there is a time-base corrector. You'll need some storage, perhaps a bucket-brigade delay-line. Obviously you will want to use real buckets...

Re: SSTV Mechanical video recorder Attempt
 

The geared motor needs some sort of syncing ..my plan today was build a sstv demodulator to get the 15 hz line sync which is varying frequency due to motor speed ...feed this into a 4046 PLL with also a clock at 15 hz for some motor control with feed back .
Problem also with a record is speed changes playing from the edge to the center...there's a lot of mechanical things going on apart from the electronic side..
I will look into the delay line idea something i have not thought of .

Re: SSTV Mechanical video recorder Attempt
 

My suggestion was at best 10% serious

Re: SSTV Mechanical video recorder Attempt
 

The pll board is probably a good idea...but first centre the disc and you could try adding a load of weight to get a good flywheel effect?

D

Re: SSTV Mechanical video recorder Attempt
 

The platter i am using is a thick bit of steel i think from an old vcr motor which could of been used for that ,just happened to be and fit what i needed here ...i will keep that on mind once i try the syncing adding more weight if it helps.
The motor is small from a video camera zoom lens 80s perhaps its geared which i needed for the lathe part to keep the platter to a constant speed when embossing the the cd dvds with a lot of friction ( viewing the speed via a strobe disc and laser to it and a photo transistor viewing on a frequency scope ) ...trouble might be syncing 15 hz is pretty slow we have only really tried it at 400 hz 750rpm for nbtv with nothing touching the disc ..here 78rpm with a bit of fiction from the play back arm ...
I think the idea Dom of using the recording sync pulses would be the way to go as you think also.
I need some sort of feed back to keep the sync pulses at the correct frequency as the motor for the platter spins the disc .
I have a 15hz clock and once i finish the SSTV demodulator i can add the sync circuit for the line frequency from the record recording feed both to a 4046 PLL for motor control ..just makes it more complex but a good test bed to see this is possible at low speeds...must be possible old facsimile machines were even slower they manage to sync them one way or another.
At the moment in the photos i posted up i am just adjusting platter speed now and then on play back trying to match line after line that's why the image's are wavy the line sync pulse's going in and out of sync frequency ...
Working more on the demodulator today..

Re: SSTV Mechanical video recorder Attempt
 

update on the project... i have upgraded to some thing a touch larger almost finished for a test record .
The darn syncing problem only way to do this simple is going old school with a type asynchronous type motor should be accurate enough .
cuts out the speed control problem which i really need this to fix for video recording .
I had an old wind up record player case.. the thing had been guttered in the 50s and some one had put in a electric motor so nothing really left original apart from the platter . i also had a 50;s player case in bad shape and did not work apart from the platter motor does 16 rpm to 78 rpm so that's interesting.
Had to make the lathe arm from old laser printer bits and stuff i had in my junk box .
i also had to make the tone arm from a Hard drive ,just wiring the last of the cables and i will start the testing again .
never give up ...

Re: SSTV Mechanical video recorder Attempt
 

Amazing! I love your creative re-use of "junk".

Re: SSTV Mechanical video recorder Attempt
 

Hi

What a great project! It's not the getting there but the journey!

It reminded me of a .pdf I produced to show the 'teenage' engineers at my company that the things that they are raving about have already been done years ago, yawn.....

pdf attached.


Cheers
James

Re: SSTV Mechanical video recorder Attempt
 

If i scrap a printer i always save the mechanical bits ,the laser printer seems always useful for these sort of projects my mechanical sstv was made from one as well .

Re: SSTV Mechanical video recorder Attempt
 

Yes they fun is seeing if you can repeat the experiment or some thing similar ,every thing invented today has an early ancestor... i sort of dislike digital electronics these days programmed chips i am fine up to the 1970s :-) i would rather keep the analog world alive !

Re: SSTV Mechanical video recorder Attempt
 

I managed to do some testing on the MK2 yesterday and today and i was still getting a speed problem which now comes down to just fiction of the recording process embossing the recording on the record .
So the problem i have been having is the recording is slowing down the platter a touch so the video plays back faster .
For now have over come this problem by eddy current braking using a hard drive neodymium magnet
So at least i can display something ..todays test recording is this youtube video
https://youtu.be/uCVSV93SQ_E

Re: SSTV Mechanical video recorder Attempt
 

Great progress! Keep on McGyvering!

Would some light oil applied to the surface of the disc reduce friction and help speed away the swarf?

Re: SSTV Mechanical video recorder Attempt
 

Thanks will do :) ,i am thinking of a variable frequency supply to drive the motor .

Also i have 100 watt amplifier for a ceramic cartridge record testing.. it works BTW to reverse a play back to a record you need around 70 watts.... the old vintage type i have doing a sweep test it go's to 8 khz a modern go's over 10 khz i hope once i do a recording to see the limit here

Would be a goal to be able to record narrow band Television i can play back comes down to the bandwidth

On your Question its used a bit by others on record lathes, i tried it on Mk1 lathe as in photos does work messy but yes ! ;)

The colour photo was a 36 sec Test recording slower SSTV i found harder on playback ..bit messy as you see manual control of the magnet to slow down the platter and get it sync ..magnet has to be very close to the platter .