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

Re: Mechanical video recorder

Postby Harry Dalek » Thu Aug 08, 2019 7:20 pm

There are a few things i need to work on now i tackled redesign number 3 of the lathe today .. so far is it vibrates with a heap of torque and sounds very good with a speaker cone to .. so i would expect higher volume recorded at least....the idea has been used before but not this small its a stepper from a dvd drive .
What i really hope for is a wide bandwidth record but see how number 3 go's.
I will more than likely have a look how well it makes tracks and records tomorrow .
I am also getting parts together to tackle the speed syncing i will use the strobe disk as an encoder reflective idea to opto switch for the mechanical feed back ...that's the start of the motor control at least
Attachments
IMG_0167.JPG
IMG_0172.JPG
IMG_0175.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: 4051
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Sat Aug 10, 2019 9:10 pm

I started working on motor syncing for now 45 rpm swapped the lid around for a place to mount the circuit board make things a bit neater .
My strobe disc i am using as an encoder is printed out on printer ink no good for an IR reflective opto switch it would not work ,so made a visible version with a laser and photo transistor ,looks out of focus in the images but its a fine dot focused to the size of the middle encoder strips .
Testing it with a frequency meter to Steve's circuit below i now know 50hz is 45 rpm .
Harry's LM311 A.gif
Harry's LM311 A.gif (6.08 KiB) Viewed 736 times

I am used a 4060 crystal 3.2768MHZ clock to 2 74hc4040's again Steve's past circuit is being reused for another project ! didn't have to think about it known working idea .
So that's built working over designed i suppose here ...look into that later if the extra locked frequencies might come in handy .
Attachments
IMG_0194.JPG
IMG_0195.JPG
IMG_0180.JPG
IMG_0177.JPG
IMG_0189.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: 4051
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Steve Anderson » Sun Aug 11, 2019 6:29 pm

Record turntables often had stroboscopes on the outside rim of the platter with four 'stripes', two for 50Hz supplies (33 &45) and two for 60Hz. They were illuminated by a neon (later LEDs) so that at the correct speed the stripes appeared stationary. The reference was usually the local mains frequency which isn't too bad, or a crystal oscillator divided down down to a suitable frequency in the higher priced models.

With direct-drive turntables they are inherently crystal controlled and usually provide no fine adjustment of speed. Higher priced ones did so you could 'tune' the record to your piano if you wanted to play along.

Steve A.

The turntable in the photo can also play 78s, but no third pair of strobe markers...I guess 78s weren't that accurate to start with...
Attachments
Turntable strobe.jpg
Turntable strobe.jpg (66.12 KiB) Viewed 725 times
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 3802
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: Mechanical video recorder

Postby Harry Dalek » Sun Aug 11, 2019 8:11 pm

Steve Anderson wrote:Record turntables often had stroboscopes on the outside rim of the platter with four 'stripes', two for 50Hz supplies (33 &45) and two for 60Hz. They were illuminated by a neon (later LEDs) so that at the correct speed the stripes appeared stationary. The reference was usually the local mains frequency which isn't too bad, or a crystal oscillator divided down down to a suitable frequency in the higher priced models.

With direct-drive turntables they are inherently crystal controlled and usually provide no fine adjustment of speed. Higher priced ones did so you could 'tune' the record to your piano if you wanted to play along.

Steve A.

The turntable in the photo can also play 78s, but no third pair of strobe markers...I guess 78s weren't that accurate to start with...


Hi Steve yes that sounds like its possible from your posting and the way to go.
I was just testing the motor control via a bistable switch feed back from the encoder and a 50 hz crystal clock dropped down from your 4040 circuits you drew up for me a while back ..its very jerky looking at the out put of the 555 bistable you can see to many pulse width changes this would not be good and isn't .
It was about the same as running for just DC lm317 adjustment by passing the 555 bistable and just using the 50hz crystal clock to switch the motor Transistor so a lot smoother than using any feed back but that has not real motor control ...
I have only tried motor control on a polygon mirror and that worked well but i know at the time the pulley had to be adjusted for correct speed control but here it has to be tight to drive the lathe or it will slip ... also being a geared motor is something new also .
May be i should of went the old 4046 way for control but any case will look into it again later this week.
(edit) ...i think a good idea would be match the pulse width from the clock to the encoders this might be helpful perhaps ...
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: 4051
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Fri Aug 16, 2019 7:15 pm

I got my embossing needle today ...i was more getting this out of interest ! the type of recording stylus depends on what you are using to record on since i am using something soft enough pretty much scratching the sound on i have to use some thing as i was doing .
007.jpg

Looking at the Needle it has a slightly elliptical cut to it than a sewing needle but i would say around the same size it seems much bigger than the gem stylus 2 i was using of late but the point might be close .
0816-2.jpg
0816-2.jpg (27.89 KiB) Viewed 642 times

0816-5.jpg
0816-5.jpg (26.67 KiB) Viewed 642 times

The stepper motor as a recording cartridge seems to work ok but looks like i will have to pull things to bits again to try this stylus or make a new one with it i can bolt on to test against .
Attachments
0816-3.jpg
0816-3.jpg (25.95 KiB) Viewed 642 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: 4051
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Sat Aug 31, 2019 10:47 pm

Sorry for any one following this I had little time last 2weeks but will get back at it .....also had to repair my store record player it's really needed just to double check the recordings ..I found out my quick knock up player worked but did not give me the correct play back quality another thing to rethink start again on.
Found the 30's clipping interesting as records were the tape recorder of the time.
Attachments
image.png
image.png
image.png
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: 4051
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Fri Sep 06, 2019 11:00 pm

At last had a bit of time to work some more on the recorder...when i left off my record player had broken just some broken wire's easy fix but before it did the last recording was not to bad the first stepper motor lathe head seems fine .
I have made another for the new cutting or embossing stylus but put that aside for a bit knowing this works and i redesigned the arm end for it trying to make it more stable during embossing and not scratch to deep or cause vibration also a shallow emboss is not good either for play back stylus.
Below first two videos what i have got up to i read a lot of people cutting records use lubrication liquid of some sort i jut used some oil here



Below a radio recording this isn't to bad now for some thing like voice this was at a slow 33rpm


Trying a frequency sweep and video recording i can hear there is some torque problem still speed difference when embossing the friction is slowing the disc down perhaps tightening the rubber pulley might help or recording a touch faster might compensate...i am finding this all very interesting as its the hardest mechanical thing i have ever tried.
Might be a good idea to record say 400 hz one frequency and see how it handles this maintaining this frequency ,so maintaining constant speed on record is my big problem ..i have removed the speed control idea for now that was not working at all .
Another idea to see whats up on the constant recording speed is view a strobe disk while recording ...any case my minds on this problem at the moment might mean a redesign ...have a head scratch and think about it :roll:
BTW coming across other recording things i noticed baird had used the idea for Noctovision recordings
https://www.americanradiohistory.com/Ar ... 7-06-R.pdf
Also came across Alberts Edikow posts in phonograph makers below
http://www.christerhamp.se/phono/noble.html
Attachments
IMG_0204.JPG
IMG_0205.JPG
IMG_0206.JPG
IMG_0207.JPG
IMG_0208.JPG
MDG_0203_x264.mp4
(6.46 MiB) Downloaded 50 times
MVI_0209_x264.mp4
(15.45 MiB) Downloaded 49 times
MVI_0214_x264.mp4
(21.45 MiB) Downloaded 51 times
Screen 00046.jpg
Screen 00046.jpg (68.85 KiB) Viewed 276 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: 4051
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Wed Sep 11, 2019 8:40 pm

My head scratching thinking time is over and back to work tomorrow ...i have come to the conclusion i really have to get the speed control problem correct so am going to have to tackle this again ,and see if i can do this a bit better .
When recording .....speed will always drop with the extra fiction automatic speed control is what i would rather ...i could view the strobe disc and try and adjust the motor speed with a fine control Precision pot it might get close or less drift but manual control it will always drift the only a matter of time .
Looking at my strobe disc i can see drift is less on 33 RPM than 78 RPM ..
I am going to print out some more strobe disks but stick to one speed software below .

Ideas other than what i am doing come to mind

Off what i am doing at the moment .. an idea on reusing records i wonder if like tape recorders you could have a erase head before the record head or erase stylus in this case high frequency feed fed to the stylus to wipe cut out the old recording ? the record stylus behind the erase stylus then cuts a new recording which i would expect be to a deeper track...Oh well just an idea that i thought might work .


Also a portable record tracking arm for any record player using the tracking arm mechanism from an old ink jet printer i think you would still have to gear the motor speed down but be usable for normal sized LP record ...

I do like the idea a few posts back using a record that already has tracks cut any old record ...a player stylus arm that is also attached to a a cutting head some distance to the recording platter ...say like a CD on a LP record the LP tracks used to move the record stylus cut on the cd ...only problem i can think of the LPs music might cause it to be recorded on the Blank ? etch a sketch fashion ? :lol: thinking aloud sorry ! :wink:
Attachments
strobo.zip
make any RPM strobe disk !
(22.58 KiB) Not downloaded yet
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: 4051
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Mechanical video recorder

Postby Harry Dalek » Sat Sep 14, 2019 11:20 pm

I began work on the platter RPM syncing again today removed the lathe stylus for the work .
Tried the IR reflective opto switch but as i thought no good for ink jet printed encoder disc's seeing right passed the ink if it were not there .. so had to reuse the red laser and and light sensitive diode positioned the laser to focus and hit the 33rpm part of the encoder i found using this at 45 rpm speed gives me 50 hz pretty much one of the out puts of the 4060 crystal oscillator to one of 4040s ,this is sort of what i was trying last time but i had trouble with room light effecting the light sensitive diode so effecting the laser pick up , the laser sensor seems better positioned this time room light change does not effect it .
IMG_0225.JPG

Haven't checked the option of the frequency results pointing the laser at the strobe disc light brake's at 45 and 78 rpm ..
Having 50 hz is an easy fix i use it to also light a diode for the strobe disc visual indicator instead of using a 240 v room light ,i have a little mirror to view bottom of the disc .
IMG_0226.JPG


I also put in a fine trimmer for the platter speed and mounted the board and controls ,the main board is out for circuit changes
IMG_0229.JPG


I have had it on manual speed control better than in the video oscillating here a hz any case reworking the speed control circuit i noticed a few mistakes to what i have made before .


The encoder pulse is a little jerky see it more on the crt scope
Attachments
MVI_0228_x264.mp4
(11.67 MiB) Downloaded 10 times
MVI_0224_x264.mp4
(3.46 MiB) Downloaded 10 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: 4051
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