New Drum monitor build

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Postby gary » Fri Jan 27, 2012 6:48 pm

AncientBrit wrote:Keep up the good work Harry.

I always look to reading the results of your latest kit.

How do you find the time??

Cheers,

Graham


It's summer here Graham, longer days... ;-)
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Postby gary » Fri Jan 27, 2012 7:08 pm

Harry, I should just emphasise, in case there is any confusion, that it is not driving the stepper harder (with voltage or current) that causes it to go faster - it is overcoming the tendency of the winding inductance to impede current flow (rise time = L/Rw) by increasing the circuit resistance (rise time = L/(Rw + Rlimiter).

Anyway, I am trying to not be too technical, but a good analysis can be found here:

http://www.divms.uiowa.edu/~jones/step/ ... #resistive
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Postby Harry Dalek » Fri Jan 27, 2012 9:31 pm

AncientBrit wrote:Keep up the good work Harry.

I always look to reading the results of your latest kit.

How do you find the time??

Cheers,

Graham


Hi Graham Oh thanks i hope when i post this stuff i hope every one finds it of interest i am glad you do ,i enjoy trying to do what comes into my head best i can with a few tools in the shed and a pile of junked this and that !

Time well i am sort of lucky in 2 ways i only have to do a 3 or 4 day week ...i'm the boss you see and my wife lets me tinker in my free time and as gary says it is summer long days ... :wink:

I have gone mounting the drums to see how it gos ,i am sort happy with the stepper speed for the large drum and i think fast enough with the pulley system but if it turns out not i have made this so mounting dc motor is just a matter of replacing the stepper with it .

The drums are a bit different this time ,i was to use 2 dvd tub drums but due to my pully system on the large drum vertical i have had to use and by luck had something handy just the right size.

The small drum will have at least 4 to 6 slits the large i am still thinking about ,i know i need as many as i can do due to the poor speed of the stepper so thinking about that ....i first planned to make this one a 60 liner but i will be happy with 32 ,the picture size more than likely even with that might be smaller than what i was hoping or planing for ...but for a start i would like to see if i can get it to work with two steppers ...i know the horizontal is no problem from the last drum and its just getting the speed for the veritical ...might have to do 32 slits and be happy with a smaller picture size ....i did want this one small oscilloscope size monitor...OH well we will see !
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Last edited by Harry Dalek on Fri Jan 27, 2012 9:56 pm, edited 2 times in total.
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 » Fri Jan 27, 2012 9:52 pm

gary wrote:Harry, I should just emphasise, in case there is any confusion, that it is not driving the stepper harder (with voltage or current) that causes it to go faster - it is overcoming the tendency of the winding inductance to impede current flow (rise time = L/Rw) by increasing the circuit resistance (rise time = L/(Rw + Rlimiter).

Anyway, I am trying to not be too technical, but a good analysis can be found here:

http://www.divms.uiowa.edu/~jones/step/ ... #resistive



Hi Gary

Just something i noticed i know theses things are generators when i had it off and turned the motor by hand either way it was lighting up my leds before my driver circuit and the 555 timers as well ...i was thinking of something i read on the forum some where using a Dc and stepper same time the Dc for speed and the stepper for braking and keeping the dc in sync with the stepper ...i gave up the idea as i was thinking this thing might will kill my circuit if i do that .

I know there must be a lot of factors to keep these things running at top speed and i know i have a bit of learning to do ..i will have a look at the link Gary .
Last edited by Harry Dalek on Fri Jan 27, 2012 10:15 pm, edited 1 time in total.
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 gary » Fri Jan 27, 2012 9:57 pm

yes, it ought to be possible to use one as a kind of "sonic wheel" - if you could find one with 32 poles - or sub/super multiple thereof...
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Postby Harry Dalek » Sat Jan 28, 2012 7:14 pm

gary wrote:yes, it ought to be possible to use one as a kind of "sonic wheel" - if you could find one with 32 poles - or sub/super multiple thereof...


Yes Gary i was not brave enough this time to try that this time ...i think the back emf might be a problem but the idea i sort of like .

Thinking about a patent i had on file a while back i have changed my design idea a little so its a bit neater since i worked out how to do this with out gearing or more the problem of mounting the light ,i always liked the double drum idea with the slanted lines so you don't have to have an upright drum or disc ,its nothing new but another nice 1930s idea .
Again thanks to gary many a post ago F. H. Haskell's Cylinder Scanning System from 1931 (Newsletter V 9/3)

The little drum is done went for 6 slits again the large due to the design will have slanted light slits many as i like really or as many as i needed to get the stepper with pulley to work...

The things more a Telehor now the way i mounted the drums...the other drum monitor did both just the image was sideways this might be the same i will find out in time /
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noticed i need a little more glue on one side :)
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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 » Sun Jan 29, 2012 6:25 pm

Hi all today i worked out how to do the slanted slits for the larger drum nice and easy so making up my mind to do a F. H. Haskell's dual drum monitor getting a little closer .

I am going to do a few of these paper Zoetrope like cylinders which just slide in the dvd drum ....this one is a 16 liner...i will do a 32 and 60 line also .

I do expect a very small picture even with a dual drum / when i try more lines.

Let you know when i do the next steps.
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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 » Mon Jan 30, 2012 4:16 pm

Lookin' good! Can't wait to see how it works :)

By the way, the X is just the letter X, not 10 lol.
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Postby AncientBrit » Mon Jan 30, 2012 6:39 pm

Harry,

How 'true' does the unsupported outer edge of the drum run when up to speed?

Does spinning it essentially get rid of wobble?

Regards,

Graham
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Postby Harry Dalek » Mon Jan 30, 2012 7:25 pm

Metallica Man X wrote:Lookin' good! Can't wait to see how it works :)

By the way, the X is just the letter X, not 10 lol.


Hi mmx :wink:
No worries .

I tried a one screw drum when i was doing my cat food tv experiments at the time ,i have gathered more knowledge since those days ..i am keen to see it running to.

With the stepper motor i expect at least 32 lines ,going to trying the other nbtv line rates this time since its adjustable ...might mean replacing the geared stepper with a dc motor but see how it gos with a stepper first.
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 » Mon Jan 30, 2012 8:20 pm

AncientBrit wrote:Harry,

How 'true' does the unsupported outer edge of the drum run when up to speed?

Does spinning it essentially get rid of wobble?

Regards,

Graham


Hi graham Wobble is always a problem and the main reason i am using a old Hard Disk drive .... i screwed that dvd drum flat to the HD platter...Wobble really depends on how true i get the drum balanced ..

Its also how well it bolted to the case ...the dvd drum is about the same as the tupperware tub i used last time any wobble was mainly due to that i found out .

I didn't really have a problem with the outer edge last time there must be a bit with a plastic drum but it didn't cause me much of a problem ,i had more trouble trying to mount the small drum direct drive on the steppers gear which wasn't very big that gave me a bit of wobble least it didn't have to run to fast .

Its more likely as you are thinking a thinner drum perhaps 25 dvd drum might be better but i am greedy for picture size .

I think because this time both drums at 0 degrees wobble should effect it less i hope :wink:

[/list]
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 » Tue Jan 31, 2012 6:47 pm

Been putting things back together today and working out places for things ..
so heres a look at stuff to date.
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Last edited by Harry Dalek on Wed Feb 01, 2012 2:09 pm, edited 1 time in total.
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 gary » Tue Jan 31, 2012 7:31 pm

Harry, only one of those images seem to have uploaded correctly...
Perfecting an NBTV system is like trying to slam a revolving door...
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Postby Harry Dalek » Tue Jan 31, 2012 9:10 pm

gary wrote:Harry, only one of those images seem to have uploaded correctly...



Hi gary i had a look seems ok my end ...have another look i reposted them so might be ok now ? but i see them fine here .

When i do some more i will post some more pictures .
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 gary » Tue Jan 31, 2012 9:14 pm

Interesting, I can only see Picture 258, the rest only come up with the name of the file.
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