Mechanical video recorder

Centralised area for notes about construction projects. Each project has its own sub-forum. In the sub-forums will be topics relevant to parts of that project (e.g., there might be a topic on motor control). If you start a construction diary, just post in the forum with your project name as the topic, and a moderator will create a sub-forum for your project.

Moderators: Steve Anderson, Dave Moll, Andrew Davie

PhonoVision PWM recording playback

Postby Harry Dalek » Thu Feb 06, 2020 2:18 pm

I was recording as in Baird Style AM to the true PhonoVision Idea apart from it NBTV standard 32 line 12.5 frames a sec and has a Sync pulse..... today i swapped to Pulse width modulation recording and i seem to be getting much better results as far as recording Grey scale so must be doing a better job and using the Bandwidth .
Got to do something about the platter speed spoils it might have another look at stepper motor here .
I would look into an oscillator feeding another high wattage amplifier to a transformer to the asynchronous Ac motor the frequency in theory should adjust the frequency ...but if i don't have the voltage i don't have the torque .
Results below end of disc so signal levels change at the end of the disc

youtu.be/hUpUE84MzpI
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Fri Feb 07, 2020 7:29 pm

I have been thinking about the platter motor again my nemesis ! :x

Experimenting with PhonoVision i now know why Baird used a monster of a gear set up to record hes video he wanted no speed change on play back of hes discs ...genius of cause !

Since i can't do this will or want i have to nut out a better solution to the speed change problem on recording playback ...(recap embossing a recording on a cd or dvd the fiction of this causes a speed drop RPM drop the asynchronous motor is not to great torque wise )
The effect on playback is correct RPM speed but the the recorded video is off sync running fast steady enough but slanted rolling ..i don't mind the wobble but a wobble in one place is better than this .

I was experimenting today with the idea a DC motor pulley connected to the asynchronous motor is sort of a superior way to adjust speed than the one way only magnetic eddy current braking at least on record i can record faster so on play back i can slow the recording back to speed.

May be with the extra torque of the dc helping the AC Platter speed may just compensate for the embossing recording and keep RPM true .

Doing a quick hook up and where i would position the motor if it worked it seems to work better than i expected ,i choose a DC motor that also has a AC signal output i am not sure what theses motors are called i have 3 one was from a old laser disc player ...Having a AC signal to view on the scope i noticed pulley connected to the ac motor and both ac and dc on the dc could control the speed of the AC and it didn't seem to drift but have to double check my scope settings might just be locking ...any case the idea is the Asynchronous mains motor stops The Dc from drifting to what ever speed its set at ...That would be nice but i will look more into this tomorrow if this is really the case......some speed control as i know this will do is a benefit much better than what i have now and an easy addition to the project .

I found out also the last posting Pulse width modulation recording was 45 RPM not 78 so that's interesting !

BTW great video on PhonoVision ...https://vimeo.com/62777765
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Sun Feb 09, 2020 4:51 pm

Ok i got my DC add on motor control built in and wired up belt connected to the asynchronous motor ,so i can now remove the eddy current idea which at least at the time slowed the platter an amount to view my recording.

DSCN6446.JPG
DSCN6446.JPG (257.37 KiB) Viewed 2785 times


The idea was explained in the last post so this is more it in images ,i would if any thing expect better results on play back to have at least some dual speed control ...until i hook up a recording to check i will see if the coarse potentiometer is enough i may add a fine if needed .

The sinewave signal out of the motor may be useful for feed back if i can be bothered going down that road....i didn't have much time today just enough to finish this idea so no tests till later in the week .



(Edit by moderator: Web-optimised video embedded.)
Attachments
DSCN6444_Segment_0_x264.mp4
(59.49 MiB) Downloaded 186 times
DSCN6444_Segment_0_x264w.mp4
(13.25 MiB) Downloaded 261 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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Sun Feb 16, 2020 4:46 pm

Just an update as i have not had much time to play with it but i did test the asynchronous motor belt driven or visa versa to the DC .
Results on the past recordings did show i could tune in the speed but the wobble was there still there when framed so i think that was in the recording in the first place ,a new recording did show it was better as far that and constant speed and wobble but i suspect a little to much play in the standard ceramic cartridge's needle might be the cause .
Any case i will have to sacrifice more cds to find out ,i would like to get to the point of stereo recording with video and audio being able to played back .
I only managed one recording before i had a regulator die on me so most of the day was on repairs testing it was not going to happen caused my Dc motor to go faulty .. and seeing if this motor better than that motor so on ... :roll:
I will stick with it has promise .
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Thu Feb 20, 2020 10:00 pm

Something that came to mind thinking about doing this instead connecting 2 asynchronous motors together
The most significant difference would be that the available torque would double. Theoretically RPM would remain the same.
I would expect this idea would help on the recording side maintaining speed due to the extra torque but i have the DC on at the moment which i need to test with more recordings but nice to have a plan B
jotting this down for my bad memory ! and any one else in the future experimenting with PhonoVision ...
I would like to see how the DC tests go tomorrow one test recording last week was not enough to see either way if this is the way to go or not /
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

PhonoVision second motor test

Postby Harry Dalek » Fri Feb 21, 2020 2:23 pm

Today i gave it a good run to see whats up i can see i can't really go any further as far as the platter speed control..... explaining ...The dc motor is handy replacement for the eddy current braking and as far as helping to stopping drift a bit i found even if the asynchronous motor is doing this the speed of the recording changes due to the tracks being shorter as it spirals in as shown in the second video so there is a constant speed change from start to end of the recording no matter what i do controlling the platter speed ,perhaps no problem for audio but video it seems to be another story ..
Baird must of had the same problem and perhaps the reason Alberts constant speed on the wax cylinder was fine as all track lengths are the same on a cylinder.
I also found due to the angle of embossing head unchanging in the recording the start to the end of the recording the video levels are higher at the start to the end ..so this PhonoVision thing is pretty hard lots of problems no wonder Baird walked away !
I did try 64 line today but as i thought i was pushing my luck with bandwidth and its all just washed out it was a horizontal scan so the roll was sideways this time .





(Edit by moderator: Alternate web-optimised versions of the videos (suffix 'w' on filename) have been added to allow "immediate" playback instead of requiring the browser to pre-load all the videos on the page.)
Attachments
DSCN9822_x264.mp4
(31.97 MiB) Downloaded 111 times
DSCN9824_x264.mp4
(50.51 MiB) Downloaded 103 times
DSCN9824_x264w.mp4
(16.88 MiB) Downloaded 281 times
DSCN9822_x264w.mp4
(8.09 MiB) Downloaded 275 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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby M3DVQ » Sat Feb 22, 2020 12:05 am

The results you've achieved are fantastic in my opinion. Far better than I expected when I first saw what you were attempting to do :)
It may not be perfect, but there's no arguing that it works!
M3DVQ
Just nod and pretend you understand me
 
Posts: 331
Joined: Sat Feb 10, 2007 10:52 am
Location: Lincolnshire

Re: Mechanical video recorder

Postby Harry Dalek » Sat Feb 22, 2020 5:36 pm

M3DVQ wrote:The results you've achieved are fantastic in my opinion. Far better than I expected when I first saw what you were attempting to do :)
It may not be perfect, but there's no arguing that it works!


Thanks there !
Yes not perfect for sure Baird would never did show he's phonoVision to the public as he was never happy with the image results at 30 line 5 frames a sec you really need some sort of long long persistence CRT to view it at that frame rate as Klaas mentioned a while back .
He was also limited to he's magnetic recording stylus head which would of been poor in Bandwidth ,i am lucky nearly 100 years later i can buy a ceramic cartridge with a 20 khz bandwidth well on play back any way it would beat Baird needle and magnetic job ,just shows that hes idea of PhonoVision was correct .
Here i think i have done better than Jeremy Jago's 2006 go as far as bandwidth he did use a standard record which is harder to record to both ways ! And Albert went the other way with a very soft wax cylinder which is difficult to play back .. i went like Goldilocks with an in between hardness just right for me soft plastic on a cd or dvd :wink: .
Well if any thing this is one off my bucket list !

youtu.be/ICje3eKTD6k
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

PhonoVision more work today

Postby Harry Dalek » Sun Feb 23, 2020 4:04 pm

Some thing i worked out today an arrrr moment when i was getting a lot of line wobble i found the cause noticing the play back arm was in sync ! i was recording at an angle .
I still have framing and platter drift ..
I worked on the control panel today adding on off switching to the DC and AC motor just to see the difference using just dc just ac and both ...the speed Control is mounted now and volume out ..i wanted get some of this out of the way and look into feeding the play back cartridge to an NBTV wideband amplifier instead just just using the put of the speaker amp which was meant just for that originally .
I feel whats recorded and whats out putting could to 2 different things
Below are some photos you can work out others are harder like my NBTV drawings and stooky bill more like a Baird recording some came out better than others .
I also need to clean things up here to also start working on Stereo recording if possible i have stereo cartridges so i would expect it is and add sound to the video recordings i don't think Baird ever did this any case we will see .
Attachments
DSCN6409_x264.mp4
(31.56 MiB) Downloaded 185 times
DSCN9915.JPG
DSCN9915.JPG (129.04 KiB) Viewed 2663 times
DSCN9913.JPG
DSCN9913.JPG (127.13 KiB) Viewed 2663 times
DSCN9891.JPG
DSCN9891.JPG (117.38 KiB) Viewed 2663 times
DSCN6414.JPG
DSCN6414.JPG (96.1 KiB) Viewed 2663 times
DSCN9919.JPG
DSCN9919.JPG (127.51 KiB) Viewed 2663 times
addtext_com_MDA1NzE5MjgzMDg.jpg
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Thu Feb 27, 2020 7:27 pm

Started work on which i hope will be an improvements 2 plans :roll: ,i was going to look into Stereo next but it would be wise to just make sure whats on the record is every bit of bandwidth feeding the monitor so working on repurposing club NBTV wide bandwidth amplifier for the job .
Also on here will be a sync detection ....
Getting my head around motor control again an idea that has come to me ... its not a camera and its not a monitor but seems similar to both in ways .
I can record the sync pulse and they are recorded on the disc and no matter where on it is it would be different spacing's depending on what record speed i choose , it has come to me the video the sync pulses would be the same as an encoder disc ...instead here i am using a stylus to pick them up than some optical or magnetic method .
So i have really a recorded encoder disc i now need accurate clock at 400 hz feed both to a PLL as in a standard club motor speed controller and it i think would a similar idea to how you sync control a mechanical cameras motor .
This way i can use the recorders added DC motor no need to think about a nightmare of an optical encoder disc for disc position feed back and its back to standard 400 hz 32 line motor speed control .
Well that's what i have in mind could fall flat on my face or it will work ...Just working on the video improvement part at the moment should have that finished tomorrow .

OH i came across this on cylinder recording chat from the 1931... makes it sound easy to record video this way but it sure isn't.. perhaps that's why you never saw a cylinder idea like this work till Alberts go .
Screen 00232.jpg
Screen 00232.jpg (145.78 KiB) Viewed 2613 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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Sun Mar 01, 2020 4:11 pm

The new board i am working on below ...repurposed club circuits .
So far i know the gamma circuit amplifiers sync separator schmitt trigger all work ,working on the DC motor controller at the moment i have to still add the 4060 crystal clock .
addtext_com_MjMyOTIzMjUwNzM.jpg


Adjusted gamma club circuit for small video level control

addtext_com_MjM1MDI1MjI3NDk.jpg


Sync detection ...i forgot to correct the 12v is 5 volts ! for this one
addtext_com_MDAwODU2MjI4MjU.jpg


Schmitt trigger and Motor control circuits
Motor change (1).GIF
Motor change (1).GIF (4.87 KiB) Viewed 2413 times

PLL 2.gif
PLL 2.gif (5.15 KiB) Viewed 2413 times

The clock will be this one
Screen 00043.jpg
Screen 00043.jpg (35.5 KiB) Viewed 2506 times

amplifier used
Attachments
DSCN9939.JPG
DSCN9939.JPG (156.57 KiB) Viewed 2507 times
TA7140P.jpg
TA7140P.jpg (12.08 KiB) Viewed 2413 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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Thu Mar 05, 2020 10:04 pm

Construction of the board is complete after testing the crystal clock now i just need to find some time to hook up and test .
Klaas has a very well thought out PDF on motor control ,i have not seen it on the forum or missed it but i be following the procedure well worth keeping not just for a look .
Lots of unknowns here motor control is for Nipkow's running at 750 rpm platter is around the 78 rpm .... but if we are just working off the pulses i hope shouldn't matter .
Everything i have tried has shown i need some thing like this , just comes down to if i manage to finding time for testing this weekend if not it will have to be next i will report on here once it do either result .
Attachments
tutorialmotorcontrol.pdf
(35.58 KiB) Downloaded 62 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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Sat Mar 28, 2020 5:56 pm

I rather not leave this project just now but i need to move on .
Going to stop work on the recorder mainly due to the stylus seems to be worn after spending a few days more testing ,i can see this in the recordings a bandwidth loss very much so on a reversing wave video.
Testing the problem it was not on play back i found a past recording that played back fine as i would of expected and this means it was on the record side ,checking it was not angle of record there was not much left but put it down to the Stylus .
Any case it will have to be on my to do list to get another from china when all this virus problem is over .
Something that surprised me as i wanted to do a few recording experiments one was recording very slow still worked 33 rpm .
Also i wanted to see speed difference in the video recording ,a very fast recording more than likely well over 100 RPM ,recording fast is easy but playing back was a problem in the past but no now i think because my stylus cartridges are the same ,you would think the tone arm would go flying but no plays very well.
The discs have that phonoVision look when you cram on the tracks ...second photo very large you can zoom into the tracks .
DSCN9984[1].JPG

DSCN9949[1].JPG


Below the end set up is pretty much lap top as the NBTV player video is fed that to a PWM circuit repurposed PWM laser modulation in this case ,then to a 100 watt amplifier feeding to the recording ceramic cartridge

DSCN9989[1].JPG


Due to the Stylus problem i could not fully test my last circuit fault finding the the recording problem it made this all pointless till i can get it going again if i have a will .

Other tests i did was again 60 line and some other formats dreadful results on 60 line more so since i again lost bandwidth with the cartridge stylus thats me in out line so its not good but i wanted to try one last time before putting this away
DSCN9972[1].JPG
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4313
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Previous

Return to Construction Diaries

Who is online

Users browsing this forum: No registered users and 1 guest

cron