Mechanical video recorder

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Mechanical video recorder

Postby Harry Dalek » Sun Jul 07, 2019 8:02 pm

Well my title is very wishful thinking but don't try never know ...See if i can get to Alberts Drum video recorder stage ...
i have not posted this project here till i tackled 2 of the mechanical problems i needed to get out of the way before i can even think about caving a bad sound signal track on a disk ..
So first was the turn table i didn't want to reuse a record player due to its size and i like to make things smaller where possible ,i am not great making stuff from scratch but repurposing junk is more my thing ...had the idea the old dvd burners might be a way to go first 2 ended up dead ends mainly due to i wanted stepper motors for the job what was on the dvd burners motor wise is not useful without gearing and fitting the geared motor for the recording arm and turn table stepper took a bit of trial and error and very much so luck with what i had handy .
What is shown todate 2 insides of dvd burners for a test bed to mount on and for the record arm ...a old large HD motor for the turn table ..a old video camera lens geared motor replacing the tiny stepper for the once laser arm ...to jerky for slow speeds...
The recording a speaker needle and other arm the stylus for play back .
This now all seems correct to at least look workable for some sound recording ...... on testing really a good 2 weeks work here and many days of head scratching almost giving up ...what i am a little worried about the stepper noise might end up on the recordings mmm..
I wanted a stepper for the turntable to test different speeds and adjust the recording speed for the audio result .

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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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Re: Mechanical video recorder

Postby Harry Dalek » Sun Jul 14, 2019 11:31 pm

What i have been up to has been testing and redesign ... first problem was replace the main stepper not because it didn't work but the noise of the stepper i could hear in the pick stylus .. that got replaced with a DC motor not what i wanted due to increased speed and less torque without a number of pulley systems but you can cut tracks with it still and it's quiet with a simple add on .
Problems didn't stop here finding nothing really recording on the tracks next looking in to the record lathe cutter there was only one thing to do and start testing it on a known working record player for testing ...i was not sure if it was the pick up or the cutter that was a problem .
Trying some hand tracking with a radio feeding the cutter on a quick turntable redesign i found my little record lathe cutter was a little to weak i was just using the output of the laptop to drive it and i was to weak i can just get a track to cutting to the cd with this set up the amp in the radio is just enough to do this as idea below .
IMG_0087.JPG


Next i used a simple quick again knock up but a better speaker this seems the right size for the job with my not so accurate tracking and angle of cut i still could manage to get some thing first go

IMG_0088.JPG

Next the set up is a very quick knock up to get some sort of result to see if i could record a sound... tests... pretty much the first short video i got the angle sort of ok on the cutter ...the other two i only put up as i recorded how i was trying this but the recorded results were crap really least i now know its possible if i can do it so badly ! all trial and error angles how hard you press it in drag it so on...have some thing to think on for for better results .


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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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Re: Mechanical video recorder

Postby smeezekitty » Mon Jul 15, 2019 6:08 am

Seems like it is being swamped by the low frequencies. Might try high-pass filtering the signal before you record it
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Re: Mechanical video recorder

Postby Harry Dalek » Mon Jul 15, 2019 8:17 am

smeezekitty wrote:Seems like it is being swamped by the low frequencies. Might try high-pass filtering the signal before you record it


Yes it's recording more the low frequencies ,I was not to bothered yesterday more just to see what cutting head worked ,I will see if I can do better next time.
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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The redesign

Postby Harry Dalek » Fri Jul 19, 2019 6:31 pm

Another redesign today might as well post up what i am up to
i need more torque to cut deeper i think ..this cut below was a very minimal cut with the old design turntable table speed to fast even on a commercial player the tracks were to close even for it to track the grove ,tried used some NBTV to record here.....some results on the CD surface nothing more than a curiosity for now .
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So looked into the Turntable design again given up on the Stepper motor tried 2 a large and a smaller one its just to noisy and direct DC motor pulley drive torque was lacking i am using now a small geared motor again out of an old video camera lens zoom ...it's not to bad lots of torque pretty quiet too out of its case ..case does let you hear it might try some felt in the case stop it being a loud speaker !
On the case it was some thing i found laying around and since i was doing this gave if a go to see if i could get it to fit with removal of the cutting head play arm and platter then it does they are easy enough to fit and remove .
Any way back to work !
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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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Re: Mechanical video recorder

Postby Viewmaster » Sat Jul 20, 2019 5:17 pm

My God Harry, you are a glutton for punishment !

If you use a speaker to cut grooves it must be damped I found.
I used a rubber pad for the speaker to drive into, to offer some resistance,
not free running as it were.

Looks like you are lateral cutting, Harry.
Edison and I ( :D ) used hill and dale cutting.

Either way, there is a very delicate balance between over and under modulation.
Too much under and the noise level goes up on playback.
Too much over and one groove runs in to the next.

I always examined my grooves under a microscope to see if the
modulation was OK and this also told me
what the highest frequency was being recorded.

Good luck. I spent a few years developing mine......
Trial and error. Trail and error......mostly error :D
“One small step for a man,"......because he has Arthritis.
Albert.
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Re: Mechanical video recorder

Postby Harry Dalek » Mon Jul 22, 2019 11:30 pm

Viewmaster wrote:My God Harry, you are a glutton for punishment !


Hi Albert or should i say my mechanical video recording Sensei ! Its been a few years since you worked on your beast and i know how hard you worked on yours ,its not easy but you did show it is possible .
I have gone for on the flat instead of a drum as it was just easier with the amount of dud cd's dvds laying around but didn't want to just use a standard record player but try it sort of from scratch repurpose of bits i had laying around to make it smaller .....that does make for punishment Yep !!!! also i felt like doing some thing mechanical again .
Using a standard player as test gear only as it will play back any thing recorded does come in handy here to show how the lathe is cutting the tracks and frequency response...i want it to also be a player to but i need to order a magnetic cartridge i had been playing with needle and tiny mic which seems to work but i am worried it will cut damage the new recordings so looking into this . I have 2 crystal cartridges handy but haven't looked into a preamp for it yet .
BTW in 2006 Jeremy Jago did some mechanical recordings this also gives me hope .
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If you use a speaker to cut grooves it must be damped I found.
I used a rubber pad for the speaker to drive into, to offer some resistance,
not free running as it were.


I sort of did that in reverse Blu Tackat the end of the speaker but Albert i will take on your advice as when i get to doing the cutting again i know i will have to experiment for best results i don't expect to luck it just hard work ideas trial and error .

What i have been doing is step back and get parts of it to work even if it means a redesign my big problem till now has been Noise getting the right motor system to work ,i am now working on the platter speed and lathe speed ...the platter i think i will adjust to 78 rpm as i think Baird used this speed the lathe motor speed is also adjustable i suppose the combination give you the record time and i know i have to get this right as tracks to close might just not work as last postings cd has shown .
Something i recall when i recorded weather satellite fax on cassette due to the slight speed changes on cassette the sync would go off ,what i did was use a pll and adjust the off sync to the wanted sync frequency insert it back onto the video ...i think i would have some problem here with off frequency sync i will have to look into if i get that far fingers crossed ! perhaps some sort of speed control on the platter motor and or sync adjustment i will wait and see how bad it is .


Looks like you are lateral cutting, Harry.
Edison and I ( :D ) used hill and dale cutting.


Yes at the moment mainly due to speaker cutting idea and size of the thing lateral cut so far ...reason mounting and i liked the idea better ; )
Found as far as cutting side of things it didn't work with the smaller speakers well not on the lateral any way but those little designs seem to work ok as a pick up device on play back

Either way, there is a very delicate balance between over and under modulation.
Too much under and the noise level goes up on playback.
Too much over and one groove runs in to the next.


BTW as its on my mind experiments with a mic to needle and mic to stylus i found the needle works as far as pick up device on lower frequency pickup where the stylus only very higher up end frequencies well the needle is a larger thing and makes sense and a stylus is tiny .
Yes Albert this sounds tricky ,i am not to bothered about the time of the recordings but more the quality so i will keep that advice on my mind !

I always examined my grooves under a microscope to see if the
modulation was OK and this also told me
what the highest frequency was being recorded.


I have a electronic microscope but also once i start the fun :roll: i will do a frequency sweep recording and also see whats happening on a spectrum scope .

Good luck. I spent a few years developing mine......
Trial and error. Trail and error......mostly error :D


I went back and was reading your experiments Albert here on the forum and its been very helpful to have something to follow in some ways ...Trial and error is my way most of the time as well you learn from your mistakes !
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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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Re: Mechanical video recorder

Postby Viewmaster » Tue Jul 23, 2019 1:49 am

Harry, I'm not sure how you are going to get sync.?
If you can record the standard NBTV sync signals we normally use
together with the video signal you are home and dry.

But I could not record reliable signals on wax so I developed an external syncing signal.
I arranged for exactly 3 frames per rev of wax cylinder to be recorded.
I could then mechanically generate 3 sync signals per rev on playback.

The radial position of these was movable around the wax cylinder
on playback to get the correct sync point.

BTW it was either Steve (Anderson)_ or Gary who told me to damp
the loudspeaker.
They were both very helpful to me during my struggles.

I do hope that you succeed in your endeavours, Harry.
I shall be watching you from afar. :D
“One small step for a man,"......because he has Arthritis.
Albert.
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Re: Mechanical video recorder

Postby Klaas Robers » Tue Jul 23, 2019 6:50 am

You do not need a needle for recording, you need a chisel, a very small chisel that cuts the material and forms a fine and well defined groove. There is coming out material, that you should remove from the surface during recording. If you look at the book cover of "de mannen van de hobbyclub" you see one with a fine brush on the disc under recording. He is removing the cut out material. I have seen long ago the recording of a 33 1/3 rpm long playing record. There a very small vacume cleaner pics up the material directly after the chisel. So no pinsel.

And the loudspeaker, you can hear the distorted sound during recording. That is also more or less, what is recorded. That sound should be fine and undistorted, and even then yoiu are unsure how the play back sound will be. You hope that it is getting better, but in reality it is always getting worse. "Rubbish in, rubbish out" is a general rule that is always aplicable. Sorry.
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Re: Mechanical video recorder

Postby Harry Dalek » Tue Jul 23, 2019 6:01 pm

Viewmaster wrote:Harry, I'm not sure how you are going to get sync.?


i am expecting it to be bad off frequency due to the cutting and rotation speed but it sounds like from your experience it will be a problem ..

If you can record the standard NBTV sync signals we normally use
together with the video signal you are home and dry.


Well that was the plan ...perhaps if there will be problems might be an idea to just see how a 32 line 400hz sync pulse records ...
On my nipkow pmt camera i synced the disk for speed control with the mechanical sync and replaced the mechanical sync with crystal made one reinserted for the video as the disk wobble was causing pulse width changes in the mechanical sync pulse ....that seemed to work only thing i have never synced something so slow ...i would expect hearing about the sync pulse problem from you Albert that it being recorded is a similar thing mmm i will have to wait and see.

But I could not record reliable signals on wax so I developed an external syncing signal.
I arranged for exactly 3 frames per rev of wax cylinder to be recorded.
I could then mechanically generate 3 sync signals per rev on playback.


Yes a good idea to remove the problem for your result , could you see the problem on the video signal as in sync there at times or pulse width or frequency change ? i will be checking this out for sure .

The radial position of these was movable around the wax cylinder
on playback to get the correct sync point.


Wonderful idea, i had thinking sort of on the back of my mind i might have to work out a syncing method but i am just worrying about one thing at a time only way to make it really .

BTW it was either Steve (Anderson)_ or Gary who told me to damp
the loudspeaker.
They were both very helpful to me during my struggles.

I do hope that you succeed in your endeavours, Harry.
I shall be watching you from afar. :D


The lathe part is a problem to get right you used a tweeter as i recall ,i will review your posts on that subject ,well first i need to see how close and accurate to 78 rpm my platter will keep to that speed , have a bit of time later in the week to work on it happy your viewing Albert ! :wink:
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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Re: Mechanical video recorder

Postby Harry Dalek » Tue Jul 23, 2019 6:19 pm

Klaas Robers wrote:You do not need a needle for recording, you need a chisel, a very small chisel that cuts the material and forms a fine and well defined groove.

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OH yes i understand some people cut their own checking with a microscope grinding the needle to shape .they do sell the record lathe cutters on ebay i am tossing up which way to go .

There is coming out material, that you should remove from the surface during recording. If you look at the book cover of "de mannen van de hobbyclub" you see one with a fine brush on the disc under recording. He is removing the cut out material. I have seen long ago the recording of a 33 1/3 rpm long playing record. There a very small vacume cleaner pics up the material directly after the chisel. So no pinsel.


I have also seen hair driers put to that use i have a little record brush i may use ...i will see if i can google your book sounds interesting hope it has pictures i can't read Dutch :wink:

And the loudspeaker, you can hear the distorted sound during recording. That is also more or less, what is recorded. That sound should be fine and undistorted, and even then yoiu are unsure how the play back sound will be. You hope that it is getting better, but in reality it is always getting worse. "Rubbish in, rubbish out" is a general rule that is always aplicable. Sorry.


That's pretty logical Klaas good advice i will be thinking about that when i test the lathe again ,there are lots of designs out there on home made record lathes ..what i have been doing is looking that the designs that seem to give good results ..a lot give bad ! :roll:
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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Re: Mechanical video recorder

Postby Klaas Robers » Tue Jul 23, 2019 7:39 pm

Harry, the title page of the book "De jongens van de Hobbyclub" (translated: The Boys of the Hobbyclub") is just a few posts up in this thread. It is a post of yours. You might not be able to read Dutch, but you can look at the nice picture.

However, reading of Dutch is not SO difficult. Read it aloud and listen to your own voice. Do not go too fast.
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Re: Mechanical video recorder

Postby Harry Dalek » Tue Jul 23, 2019 10:21 pm

Klaas Robers wrote:Harry, the title page of the book "De jongens van de Hobbyclub" (translated: The Boys of the Hobbyclub") is just a few posts up in this thread. It is a post of yours. You might not be able to read Dutch, but you can look at the nice picture.


Yes i have not been able to find the whole book magazine ,i really liked the cover ...experimenting having a go

However, reading of Dutch is not SO difficult. Read it aloud and listen to your own voice. Do not go too fast.


I will give it a go when my wife is not around :lol: these days a lot of words are international so least you get the an idea via one or two words of the subject /
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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Re: Mechanical video recorder

Postby Harry Dalek » Wed Jul 24, 2019 1:59 pm

Just posting up information on the subject of interest ....My next step is turntable speed i want to see what drift i have ,using a 50hz a Stroboscope Speed Test Disc ,for music not so much a problem but video line timing ...i have no idea how bad it would be but 50hz Pll motor speed control might be the next step if the bugger drifts to much bit of mechanical feed back and a crystal with some division ...something similar to the 400hz motor control system for nbtv but much slower might work ? but getting ahead of my self :roll:
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Below similar idea in this poor newspaper scan to Alberts drum ,i found that baird had played with the idea of using a Edison drum system to not sure why he gave it away for the record may be just because it was the new thing ?
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On the playing Stylus this is helpful for me ..have to get my Edison type needles out have a look at them ..

need47.jpg


The cutting stylus wedge Klaas mentioned i should look into seems to be lots to learn on this project
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Closest idea to a video record player monitor i have come across from the time
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Below other information i have found on the mechanical video recording idea

Radio News bit of wishful thinking below !

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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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Re: Mechanical video recorder

Postby Viewmaster » Wed Jul 24, 2019 4:49 pm

Harry in fig 1 the drawing shows an important aspect of cutter design.
The burnishing facets are critical in order to get a
smooth, shiny finish to the cut disc.
Without them and the right angle of attack you
will not achieve smoothness and so low noise level.
I stoned my facets with an engineers stone but you
cab buy a cutter already made......eBay :)
“One small step for a man,"......because he has Arthritis.
Albert.
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