The holtzman CDM

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Postby Harry Dalek » Sat Nov 19, 2011 12:07 am

Hello been working out a few things i need to do on the monitor...working out the control panel ...had to remake a power supply thats finished and at the moment rewiring trim pots switches to panel switches and panel pots..bit of a pain but needs to be done ..mounting the circuits in that case under the motor ..the power transformers under there as well if your wondering .
Slowed me up a bit but better than having circuit boards hanging off every where ..i'll let you all know how there rest go's.
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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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just a hint or tip

Postby bigscreen » Sat Nov 19, 2011 9:04 am

I m following with wondering eyes your progress at this cool project some time now, and I can't resist to give a small hint or suggestion to become a better result in the picture.
The drawing will make it clear what I mean (think so).... :wink:
Go for it !
Wonderfull job so far ! Congratulations!
Patrick.
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Re: just a hint or tip

Postby Harry Dalek » Sat Nov 19, 2011 6:42 pm

bigscreen wrote:I m following with wondering eyes your progress at this cool project some time now, and I can't resist to give a small hint or suggestion to become a better result in the picture.
The drawing will make it clear what I mean (think so).... :wink:
Go for it !
Wonderfull job so far ! Congratulations!
Patrick.


Hi Patrick Glad to see you back after a year or so !

Thanks for the hint ,the reason i have not done the full drum in black is i still have to try to sync the drum and sync the small drum to the large and i am at first trying the line slits to work the light braker for the monostable clock ..
It didn't work on the past drum as there was to much wobble to the large drum ...if it still does not work i need to use that back clear bit of the drum i plan to cut out a round bit of black paper and put holes in for my light braker if not for the small drum for syncing it as in the clubs sync 4046 circuit once i get around to it .

Main reason to for not painting as with a cut out black paper if i make a mistake i just have to make another and i can adjust it to ideas .

I will stick some photos on with progress later to night i have the motor circuit board just about rewired up ..a lot of work rewiring !
:roll:
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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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Question...

Postby bigscreen » Sun Nov 20, 2011 12:30 am

Great job so far, okay,......

I m not sure with the speed 1500/min, if this is correct, and if it is correct that the smal drum has to spin slower 4 times, but even if this is not what I tought, it don't matters with what I m trying to explane in my drawing now, but I tought that this is a correct way to have a good solide connection with the two drums,....
The signal from the cd could be used to get the sync holding the big drum in syncronisation, and the big drum could make the signal for the small drum wich I believe will spin in sync with the synced speed of the big one.
Just a tought of how I would try it out ofcourse....... :wink:
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Re: Question...

Postby Harry Dalek » Sun Nov 20, 2011 4:09 pm

bigscreen wrote:Great job so far, okay,......

I m not sure with the speed 1500/min, if this is correct, and if it is correct that the smal drum has to spin slower 4 times, but even if this is not what I tought, it don't matters with what I m trying to explane in my drawing now, but I tought that this is a correct way to have a good solide connection with the two drums,....
The signal from the cd could be used to get the sync holding the big drum in syncronisation, and the big drum could make the signal for the small drum wich I believe will spin in sync with the synced speed of the big one.
Just a tought of how I would try it out ofcourse....... :wink:


Hi Patrick Thanks once again for your input you have made a lot more working mechanical tv's than i ever have so i do listen don't worry.

I am not sure about the 1500 speed as well i would say its a bit slower since i have 2 more slit lines .
holtzman has told me its 12 rotations to one rotation of the 6 line small drum ...he has 12 lines large and 6 small gives the correct aspect ratio as well ..mines 14 ,6 and due to its smaller size gives a more 4.3 look i'd say.

So yes the small drum has to run much slower...using 2 drums or discs gives a nice picture size i think theres nothing like it till you get to a mirror screw for size but i like the design better as back lighting looks better than front lighting.

Looking at your block diagram i will look into it good to do things correctly ,but running the thing on manual i have found the small drum due to the stepper motor idea again from holtzman gives me no trouble at all free running its no harder getting a picture on this with manual control than on a nipkow one disc.


Yes on the large drum controlling the small this is how holtzmans cdm works...but on hes he is using a mechanical light braker to drive 4 mosfets which is a replacement for the stepper motor electronic ic's ,i am using the electronics to drive the stepper and trying one light braker which will drive a monostable, the timer my clock for the system i can at the moment switch between it and my free running Astable clock when i get around to it i will try either just using the monostable triggerd by the light braker or using it the monstable to sync in the 555 timer Astable multivibrator one way should work...worst case it works in manual control and i can still get a picture .

I have been wondering about 60 line i am wondering if its twice the speed with out playing around with the line slit numbers my drum motor could do it is from a 80s video disc player ...vibration at very high speeds could be my only problem mmmm
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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Slit numbers

Postby holtzman » Sun Nov 20, 2011 7:46 pm

Hi there and welcome back Patrick!

I must make some correction for you Harry. I never told there are 12 lines in my large drum. The math here is very simple and don't waste your time for just experimenting with things which are wrong because of some misunderstanding...

So regarding the lines' numbers, I have: 16 lines on the large drum, and 6 on the small one. Because my speed is doubled, I need half of the normal amount of 32 lines.

Regarding how to blacken the intervals between the lines: I do believe that even in Australia the electric isolation tape is the same PVC roll 3/4" wide. If you use black color type, it's completely opaque and I even used it to form lines not just to blacken the intervals.

Best luck!
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Re: Slit numbers

Postby Harry Dalek » Mon Nov 21, 2011 12:07 am

holtzman wrote:Hi there and welcome back Patrick!

I must make some correction for you Harry. I never told there are 12 lines in my large drum. The math here is very simple and don't waste your time for just experimenting with things which are wrong because of some misunderstanding...

So regarding the lines' numbers, I have: 16 lines on the large drum, and 6 on the small one. Because my speed is doubled, I need half of the normal amount of 32 lines.

Regarding how to blacken the intervals between the lines: I do believe that even in Australia the electric isolation tape is the same PVC roll 3/4" wide. If you use black color type, it's completely opaque and I even used it to form lines not just to blacken the intervals.

Best luck!



Hi sorry yes you are right brain dead last post should not be typing after a lot of soldering .
I sort of wonder it matters that much a few slits here or there as its the speed the drum rotates gives the number of lines not the number on the Drum i think you can just adjust it as you say twice the speed for your number of lines gives 32 i don't think it has to be even or odd number lines to give 32 just the right speed ...the original 1930's system was 12 12 on both drum or disc systems ...i think this is why the 12 was in my head!
I suppose the more lines slits the smaller the picture and easier for higher line definition thats why i am sort interested now in seeing what speed and different line number slits can do ,if you think about it on vibrating mirror systems that were tried they just had a mirror or two rocking to do the same sort of thing so speed of the rocking would of changed number of lines ....i can see this working very much so playing around with the speed of the drums ...

But i do understand both drums working off each other might give a different results which i will find out ...i never knew it would work manually
till i tried and would of said before hand no way but it does .

I am pretty happy with the paper i am using for the slits just had it handy and it works i like it because its matt black no other reason handy + was something i didn't have to buy ...

I will keep on experimenting on you monitor design i love it ,got to be the best of 2011.
Last edited by Harry Dalek on Mon Nov 21, 2011 7:22 pm, edited 1 time in total.
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Wondering about it.....

Postby bigscreen » Mon Nov 21, 2011 1:02 am

Hi there Harry, and hello again Holtzman..... :D

It gives indeed a much better and bigger picture this way, and less harder to create this monitor than suffering with making a heavy mirrorscrew.
I wonder if there are no substitutes to create a mirrorscrew in one part, something like a plastic molded mirrorscrew, which could been silvered with those smal silvertape they use in some isolation-technics.
A moulded mirrorscrew, who has not to been adjusted anymore, and it would no longer need a big motor to drive it.
I think that the cost's to manufacturing some nbtv disc's are not much cheaper than make a mould and use some flowing epoxy...?
Just some idea's from me......and there is always time for a smile to.... :D
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Re: Wondering about it.....

Postby Harry Dalek » Mon Nov 21, 2011 8:11 pm

bigscreen wrote:Hi there Harry, and hello again Holtzman..... :D

It gives indeed a much better and bigger picture this way, and less harder to create this monitor than suffering with making a heavy mirrorscrew.
I wonder if there are no substitutes to create a mirrorscrew in one part, something like a plastic molded mirrorscrew, which could been silvered with those smal silvertape they use in some isolation-technics.
A moulded mirrorscrew, who has not to been adjusted anymore, and it would no longer need a big motor to drive it.
I think that the cost's to manufacturing some nbtv disc's are not much cheaper than make a mould and use some flowing epoxy...?
Just some idea's from me......and there is always time for a smile to.... :D


Hi again Patrick ...Yes its a wonderful design ,i think the only reason it was not a popular monitor in the 30's was they made the mistake of over Engineering using big gears making them noisy ,no wants a steam train in the living room ! They had another way to fit the drums so Holtzmans design is as far as i know Unique .

I really think its kicks the big A to a mirror screw ...no need for the right viewing distance no need for the right viewing angle no need for a thin light some distance from the screw ....but its not one its its own thing and the monitor i think would catch on if others give it a go ...i found it to be a very enjoyable build ....which is on going

:wink:

Nice one patrick i would never think Baird would need help from me Blasphemy!!!!Blasphemy!!! :shock:
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Postby holtzman » Tue Nov 22, 2011 8:08 am

Oh, thanks for your superlative reviews :oops: A friend of mine told me already that it's cute that I improved something that had already died in the past, and was surprised how I admire the past and love things gone with the progress.

Mirror screws are still more compact and light efficient. But unfortunately they can not be moulded for many reasons. They can not be made using modern laser-modelling techniques, too. Each way of reproduction either affects mirror quality, or the whole thing's geometric accuracy.
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Postby Harry Dalek » Tue Nov 22, 2011 5:37 pm

holtzman wrote:Oh, thanks for your superlative reviews :oops: A friend of mine told me already that it's cute that I improved something that had already died in the past, and was surprised how I admire the past and love things gone with the progress.

Mirror screws are still more compact and light efficient. But unfortunately they can not be moulded for many reasons. They can not be made using modern laser-modelling techniques, too. Each way of reproduction either affects mirror quality, or the whole thing's geometric accuracy.



Hi still like your design over the mirror screw for one the screw is stuck at so many lines yours is really adjustable really only limited to the motor speed...once mines finished i will be testing other line rates /+ really easy once you get the hang of it to remake different drums.
How many tv's can you make out of a Tupperware tub :wink:
I will buy some of the clear plastic once i find it but the tubs seem ok for now.

OH btw they did make a moulded mirror screw towards the end i think it was made out of bakelite the stuff old valve radios were made from and coated . And yes those things seem pretty fussy and costly to make right , again screen size yours might not be as large as a screw but hell easier to make.

OH on the 1500 speed thing i think you misunderstood i was meaning with drums of different line slits the speed would change more or less depending on the number of line slits on your drum to view 32 line ...yes 16 line slits twice 750rpm but because you have 2 drums or a drum with different number of slits this speed can change to view the same thing line system ,i think this means your monitor is a multi system nbtv.

I see the line slits number used on the drum really more for the screen size ,and motor speed changing the number of lines and this is limited to motor speed .

I have been studying your design / :idea:
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 Nov 24, 2011 9:27 am

Well almost there ,after working out my Ac transformer was not up to running 2 motors and 6 watts of luxeons i have gone back to the transformer i first was going to use ...now that will teach me !

I was loosing voltage just as i started to run it all, bit of a no brainer what the problem was .

Now since i have a bit more control with it this is what i have found ...adjusting the speed of the stepper increases and decreases the picture definition ...You can remove any vertical bar by over speeding the stepper motor ...dropping the speed increases the definition but you get a black bar across the picture ...interesting effect also increasing speed you increase image size visa versa again ..

I still get a bit of picture roll and such i have not worked on that yet i still have not tried Gary's idea for video inverting ,so monitor still needs some work but i am happy with what i see so far .

Oh and one other thing on the stepper adjusting the speed really doesn't cause any roll in the picture thats only what the main drum does adjusting to the right speed ..

You learn a lot running these things in manual.

I will try and upload some some pics for this post .
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what it looks like todate
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Postby Harry Dalek » Thu Nov 24, 2011 11:19 am

I had trouble uploading the video so its here on you tube
http://www.youtube.com/watch?v=HUXDaRPr-Fs

http://www.youtube.com/watch?v=YmIb1XGG03c

I don't think i will ever go back to one motor designs after playing around with this ..i used to think these would be harder anything using 2 motors but i think its the other way around !

In the future i plan to drop the size of the monitor again without decrease in picture size i am really glad i have experimented in manual control now .
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This is the stepper a bit slower notice the bar thickness
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This is the stepper speed up a bit notice the bar and increase picture size
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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 Dec 15, 2011 12:26 am

I haven't really played with moving video with the monitor just before i start on the sync heres one last look at manual 2 drum control.
First video is Marx handshake Tekade system i videoed on the side for this.

Second is porridge baird system .

:wink:
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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 Metallica Man X » Thu Dec 15, 2011 5:29 am

That thing is a beeeeaaast!

you could smack down a yak with that :lol:

Can't wait to see it running with sync!
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