Making the smallest Nipkow NBTV, THE NIPKOW NIPPER.

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Making the smallest Nipkow NBTV, THE NIPKOW NIPPER.

Postby Viewmaster » Fri Nov 11, 2011 1:02 am

Further to the other thread about small Nipkows.
I have got the tiny bug......

I am making a jig to hold my old Ensign Selfix 120 rollfilm camera (104mm lens), together with the club's Nipkow disk on the same rig, mounted approx 2 feet from the camera to get my 2 inch dia Nipkow disk image on film. This image cut out to form a 2 inch dia Nipkow disk, to be sandwiched betwee 2 large washers for film stability.

The film is Fujichrome reversal. 12 shots on one film to give various exposures for best results.

Also going to use a piece of frosted material positioned where the Ensign Selfix's camera's 120 film runs to examine the camera's image of the Nipkow disc to get the camera focus correct. (Close up lenses required.)

Just recapping, the club's Nipkow disk's image on 120 film will be 2 inches diameter, so the NBTV picture will be approx .2 inches x .120 inches. from this spinning disk.

The resulting Nipkow scanning image holes will be .004 inches dia and the sync holes about .012 inches dia. I am hoping that the opto fork will sense these tiny holes and not require a seperate larger sync wheel as I wish everything to be kept small.
A large 10mm ultra bright LED positioned right up to the spinning disc will
give enough illumination, I hope, to overcome the poor light threwput from the .004 imaged spinning holes.

The tiny camera ordered from ebay for £5 will pick up the NBTV image,
I hope !
(using an experimental close up lens) from the spinning film and show it on one of those car reversing LCD displays.(about 3 inches high. ) so one can see the tiny image on the spinning film just above the big LCD display.

Will it all work? Any suggestions please?
Last edited by Viewmaster on Mon Oct 01, 2012 11:47 pm, edited 3 times in total.
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Postby holtzman » Fri Nov 11, 2011 7:53 pm

There are two fundamental obstacles for it to work properly.

First, the film contrast. I learned - from this forum - that no film is sufficient to give 99.99% black as required for NBTV.

Second, the disc mounting on a shaft. Even if you manage to make an accurate disc, its center must be drilled by exactly the same diameter as the shaft and exactly in the holes spiral's center. With dimensions you are talking about, it's very challenging...

Anyway, if you overcome these obstacles, it will be very interesting to try to PROJECT your spinning disc image on a small screen. I have been thinking about it quite a while. Because high power leds are so bright, and their light is concentrated to such a small area, they can act just like a light source of a slide projector, diffusor included. So there may be enough light for a 2" screen! It may be a substitute for a lens disc.
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Postby Viewmaster » Sat Nov 12, 2011 3:09 am

holtzman wrote:There are two fundamental obstacles for it to work properly.
First, the film contrast. I learned - from this forum - that no film is sufficient to give 99.99% black as required for NBTV.
.

Thanks for you input........
That's true about contrast, but better a tiny NBTV with a bluish background than none at all I think.
In any case I might try to register two film images. This from tests carried out gives a dead black background.

holtzman wrote:Second, the disc mounting on a shaft. Even if you manage to make an accurate disc, its center must be drilled by exactly the same diameter as the shaft and exactly in the holes spiral's center. With dimensions you are talking about, it's very challenging...
.


I wouldn't attempt to do that..........
I shall be punching an OVERSIZED shaft diametre hole in the centre of the film so that the 2" dia film can float about freely on the shaft.

The film will then be 'lightly' clamped betwee the 2 washers.
Using big magnification I shall look at all the outer 32 sync holes in turn against a fixed datum edge, rotating the disk as required now running on the shaft's final bearings.

A 2BA leadscrew will then be used to gently nudge the film back and forth bit by bit until all the sync hole edges line up with the datum.. Providing the club's disk sync holes are true relative to the scanning holes and to the original centre hole It should be possible. The final clamp nut then tightened up, locking the film between the washers.

As the scanning holes images are only .004 " dia we are looking to get an accuracy approaching .001 "
Even that would give scanning under/ overlap on the NBTV picture
so it's going to be tricky, but then I like tricky problems ! :-)

holtzman wrote:Anyway, if you overcome these obstacles, it will be very interesting to try to PROJECT your spinning disc image on a small screen. I have been thinking about it quite a while. Because high power leds are so bright, and their light is concentrated to such a small area, they can act just like a light source of a slide projector, diffusor included. So there may be enough light for a 2" screen! It may be a substitute for a lens disc.


The 10mm LEDs I have illuminate evenly all the area required for this tiny picture.
As I said a tiny camera will be used to capture the tiny image and present it onto a 3" high display.

The opto fork is a non starter as film does not obscure the emitter I have found.
I am experimenting using the club's dome light sensor (used for the club's camera). Well masked to pick up the .012 dia sync hole images
any slight voltage rise should be capable of being detected and hence sync pulses formed.
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Postby Viewmaster » Sat Nov 12, 2011 10:50 pm

holtzman wrote:- that no film is sufficient to give 99.99% black as required for NBTV.

A few more thoughts.....
If you wish to experiment using film the 99.99% black might be partially overcome, either by fixing extra film blacked segments in between the scanning holes or using a black film paint. (Painting as near to the holes as one can with a fine artist's brush with a width just slightly more that the NBTV picture width.)

Although this might not cover all the original black areas right up to the scan holes (depends on your skill as a painter!) it would eliminate the leakage through the film, except just the small section next to the scan hole image.

If you do try to make a tiny NBTV Nipkow disk I would like to know how you get on, using film or otherwise.

I find that combining NBTV with photography using film is rather pleasing,
that is, if it can be done !! :-)
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Postby Viewmaster » Mon Nov 14, 2011 10:00 pm

Have received the mini video camera and adapted it for huge close ups.
For test purposes the picture shows the end of a biro, the ink can be seen on the biro ball at the bottom of the photo as a mottlerd area. Taken in a a dull room without any lighting !
The LCD screen (a car reversing monitor !) is 4 inches long to give an idea of the magnification.

Depth of field is tiny so looking at a 3D object is difficult. NBTV will only be flat so no problems there.

I shall increase the magnification even more to see the sync hole images on the 2" dia Nipkow disk film image to align up the scanning holes.

The magnification will then be reduced for the NBTV film image, which you may remember, was approx .2" high.

What an amazing mini cameras these are all for £5 !!.......and what a great stocking filler they would make . :-)
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biro ball .jpg
Mini video camera adapted for close ups.
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Postby gary » Mon Nov 14, 2011 10:34 pm

aaah, but the external sync?...
Perfecting an NBTV system is like trying to slam a revolving door...
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Postby Viewmaster » Tue Nov 15, 2011 12:46 am

gary wrote:aaah, but the external sync?...


Now that is the question, Gary.
I must confess that I was impatient waiting for the mini to arrive from China so bought one from the UK just to try out.
No ext sync on the one I have and shown here.....maybe the one from China will have sync ? ...........

As Chinaman say, " Me havee sink in Chineese laundry!" :-)
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Postby gary » Tue Nov 15, 2011 11:21 am

I take it there is no (obvious) access to the digital connections at the back?
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Postby Viewmaster » Tue Nov 15, 2011 7:28 pm

gary wrote:I take it there is no (obvious) access to the digital connections at the back?

No Gary I don't think there are. Just the power socket and two phono plugs.
One is connected to the monitor but there is no info in the little instruction book as to what the other is for, although it states that the camera provides audio function so I guess it's for audio o/p, but no sign of a mic.

Although the booklet states that various lenses are available and infra red can be added there is no manufacturer info ( Name/address/phone number)..........the inscrutable Chineese! :-)

But for £5 it does what I want it to do, so I am well satisfied.

Gary, for digital connections you will need something like this at a pricey £9 !! ;-) ................

http://www.ebay.co.uk/itm/200459396933? ... 1436.l2649
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Postby dominicbeesley » Tue Nov 15, 2011 9:58 pm

Hello Albert,

This sounds like an interesting project. I'll be watching your progress.

As to the sync for the disc if you are happy to use modern electronics then you could make a single frame sync on the disc, splindle or whatever then turn this back into 31 line syncs and a missing with a few logic chips or a uProcessor...feed these into a normal sync circuit.

Otherwise it might be worth investigating just comparing frame pulses. This should give perfect framing but will need good phase accuracy to prevent lines going awry.

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Postby Viewmaster » Wed Nov 16, 2011 1:26 am

Hello Dom, long time no see. (at Loughboro about 2 years ago?)

Thanks for your suggestions which I will bear in mind if all else fails.
........and knowing me, I bet it will!
Using your single frame on disc and cooking it up into 31 is a good idea.

But I am sure you will agree that picking up the 31 pulses from the sync pulse hole .012 dia images on film will be more satisfying, and a true copy of Nipkow's bigger 12" diameter big brothers, so I shall try that approach first.

Progress is, Dom, that I am awaiting some tufnol to make long extension tubes for the mini camera's lens and hence the huge enlargement for film Nipkow alignment.

The 120 rollfilm camera jig to hold the club's 12" Nipkow up to the sky for silhouhette shots near completion.
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Postby kareno » Wed Nov 16, 2011 3:44 am

A while back I made a Nipkow disk out of OHP transparency. I wouldn't recommend that for this situation because the printer resolution (600pdi) was only just adequate for my 20cm (8inch) disk.

What I can suggest is a way of overcoming, to a large extent, the problem of light seepage through the black areas. I made a second disk of an opaque material and punched the holes with a leather punch. Fixed together with the transparency disk, the transparency-defined holes were visible though the punched holes, leaving a relatively small area of blackened transparency.

This greatly reduces the light seepage. The result is theoretically a bright, sharp image defined by the transparency apertures, overlaid with a dim, blurred image defined by the punched holes and the black transparency that shows through them.

This worked well. It is the same disk I used with my camera converter:

http://www.taswegian.com/NBTV/forum/vie ... php?t=1306
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Postby Viewmaster » Wed Nov 16, 2011 7:07 pm

kareno wrote:A while back I made a Nipkow disk out of OHP transparency. I wouldn't recommend that for this situation because the printer resolution (600pdi) was only just adequate for my 20cm (8inch) disk.

What I can suggest is a way of overcoming, to a large extent, the problem of light seepage through the black areas. I made a second disk of an opaque material and punched the holes with a leather punch. Fixed together with the transparency disk, the transparency-defined holes were visible though the punched holes, leaving a relatively small area of blackened transparency.

This greatly reduces the light seepage. The result is theoretically a bright, sharp image defined by the transparency apertures, overlaid with a dim, blurred image defined by the punched holes and the black transparency that shows through them.

This worked well. It is the same disk I used with my camera converter:

http://www.taswegian.com/NBTV/forum/vie ... php?t=1306


Yes, the closer the diameter of your punched holes to the scanning hole image diameters, the less the seepage.

One thing that is interesting is that most folk film a NBTV set up with their video cameras with the camera the normal way up. ie, their camera scanning lines are horizontal, at 90 degrees to the NBTV vertical scan.
This results in frame slip that we often see.
I shall be able to arrange the PAL scanning lines to be in line with the NBTV scan if I wish, and I wonder what the result will be ?
Maybe the picture will roll sideways ??
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Postby Viewmaster » Tue Nov 22, 2011 11:47 pm

Here's a photo of the 120 rollfilm camera jig, made to photograph the club's Nipkow disk, which is seen mounted at the far end of the jig.
Went outside this morning with an overall grey sky and took shots of the Nipkow pointing up at the sky at various exposure times and camera apertures.....off to the
film processors tomorrow.
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Camera jiog.jpg
Camera jig for Nipkow disk.
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Postby Lowtone » Thu Nov 24, 2011 9:37 am

Viewmaster wrote:
gary wrote:I take it there is no (obvious) access to the digital connections at the back?

No Gary I don't think there are. Just the power socket and two phono plugs.
One is connected to the monitor but there is no info in the little instruction book as to what the other is for, although it states that the camera provides audio function so I guess it's for audio o/p, but no sign of a mic.

Although the booklet states that various lenses are available and infra red can be added there is no manufacturer info ( Name/address/phone number)..........the inscrutable Chineese! :-)

But for £5 it does what I want it to do, so I am well satisfied.

Gary, for digital connections you will need something like this at a pricey £9 !! ;-) ................

http://www.ebay.co.uk/itm/200459396933? ... 1436.l2649


I love those CMOS cameras
I asked if it could be converted to 32 lines, or if someone could manufacture one, but it seems hopeless :arrow:
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