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Multi-standard 3 spiral Nipkow disc televisor

PostPosted: Fri Jul 27, 2012 6:26 pm
by aussie_bloke
G'day all.

In the past few weeks I have been working on and off in the background on another Nipkow disc televisor with a twist of course, this project I am working on is a multi-standard Nipkow disc televisor consisting of 3 spirals of holes (60, 32 and 30 line) and both horizontal and vertical scanning! This set should cover the set standards of NBTV, wide screen 32 line, John Logie Baird 30 line, 60 line horizontal. As for TeKaDe 30 line horizontal, I will have to make the motor somehow rotate clockwise to make it work.

For the disc I decided to use an LP record this time (no it's not a Kamahl record lol) and I drilled 60 holes on the outer region of the record, 32 holes in the middle region and 30 holes on the inner region. For the template I used Gary's DXFNipkow program. For the drill bit, I used a sewing needle so the holes can be small enough for good resolution and minimal overlap.

The motor to be used is that 1940s sewing machine motor as it has a nice vintage look and works quite nicely and it spins anti-clockwise, just need to figure out a suitable speed control for it and possible synchronisation would be great, will work that out later on. I've decided to belt drive the disc too instead of direct drive.

For the woodwork and cabinetry and other bits and pieces I have been doing some Steptoe & Son junk runs picking up useful items from curbside junk piles and have picked up a little wooden desk with drawer which I thought would make a great base/stand for this set. Also visited the local tips and picked up an old drawer which I think would be perfect to house the disc in. I also have picked up from the junk piles other great items including junked printers which gave me cogs and spindle rods and many other useful items, cupboard drawers which will come in handy for any cabinetry work for my projects, and picked up other useful pieces which will be great for the project and other projects.

Working on the drawer which will house the Nipkow disc record, I replaced the draw bottom with plywood as it had woodplanks that were curved up from age and weather, I cut out two rectangular sections in the plywood for the horizontal and vertical sets of LEDs and drilled a hole in the centre for the disc, I placed a plastic cog in the centre hole so the spindle rod can easily slip in and rotate with not too much friction.

The LED banks I used two plastic pieces from the plastic offcuts from one of the junked printers as bases to mount the LEDs on, I did some careful measurement and marking of where I am going to situate the LED clusters for each set of spirals and marked/drilled the holes in the plastic bases and ground the edges of the LEDs so I can mount them very close together. The resistors at the back are 100 ohms each driving 4 LEDs. I made the LED clusters a bit bigger than the scanned area to compensate for any slight miss-positioning of the LED bank sets. I am yet to make the hoods for them with the light diffusers but endeavor to do so soon, as suggested by Harry I will use plastic off a milk bottle as the diffuser and have an empty milk bottle ready to cut.

Next I was thinking about how I am going to mount the motor and was debating on whether to directly or indirectly drive the disc, I decided to indirectly drive the disc with a belt and spindle as it would be easier to mount the motor without too much precision with the motor's height position, plus I can easily change motors should it not work up to par. So I decided to have the disc mounted on a spindle rod which will be belt driven by the motor, for the rod I used a rod from a roller of on of the junked printers, cut a section of it which had a gear cog firmly stuck to it which I think will be great to glue the disc onto. I used another gear cog to mount into the centre hole on the drawer bottom so the spindle can freely rotate with minimal friction as previously mentioned. For the motor I made a wooden frame to mound it on plus a rear support at the top for the back end of the spindle which is an aluminum tube mounted in the wood cross beam at the top of the frame. I have mounted the frame to the desk using 4 long bolts and mounted the motor to the frame using the screw underneath and screws at the front.

Testing the belt drive, I have done a couple of tests with a couple of belts and the spindle successfully moves but the belts tend to slip and ride up and down the spindle rod shaft so I will have to mount a pulley cog onto the spindle. As for the friction, it's quite good at the front end due to the plastic cog but there is a fair bit of friction at the back end due to the slightly tilted aluminum cog and pull pressure from the belt, little teething troubles but I will work them out.

Anyhow the project is far from testing stage yet, much more to construct but it's coming along nicely so far!:D Here below are pictures of the construction progress of this multi-standard televisor:

PostPosted: Fri Jul 27, 2012 6:28 pm
by aussie_bloke
Due to limitation of 20 attached images at a time, here's the last few images of the construction work:

PostPosted: Fri Jul 27, 2012 11:43 pm
by Steve Anderson
There are various limits imposed on this forum which are not set by Andrew, Dave or myself. They appear to be set by But by and large the limits are reasonable.

There's a 20MB individual file-size limit for attachments, the way around that is to say you have such-and-such a file and members request it, or upload it to your own web-site if you have one a place a link in the post here. Or break it into bite-sized pieces using Winzip (disc-spanning).

I wasn't aware there was a limit to the number of attached photos but that's obviously easy to get around.

There is also a 50-limit to non-picture attachments (pdf's etc) in a single posting.

It can be a little frustrating, but considering the cost to all of us (except Andrew) you can't complain...

Steve A.

Actually it's called Splitting Zip Files rather than disc-spanning, but both exist within Winzip...they are different.

PostPosted: Sat Jul 28, 2012 12:24 am
by aussie_bloke
Thanks for the info Steve. I have no complaints whatsoever with the limits of attachments in these forums, I think they are more than reasonable in comparison to other forums I post in and I don't even need to compress my images which is a good thing :), I was just stating due to the 20 image per post limit I had to post the remainder in the second post.

PostPosted: Sat Jul 28, 2012 12:51 pm
by Steve Anderson
Ah, I didn't intend to make it seem that you were complaining, it's just the way that sentence came out. I should have composed it better. My apologies.

Steve A.

PostPosted: Sat Jul 28, 2012 1:44 pm
by Steve_McVoy
Here is an old multistandard scanner:

The disk has 24, 36 and 48 hole spirals

PostPosted: Sun Jul 29, 2012 8:51 pm
by aussie_bloke
No worries Steve, I wasn't sure whether you were or were not so felt I had to clear things on my part anyhow. Of all forums I've posted in, this forum is the most generous with allowances for file size limits and quantity of files per post and I think that's excellent!:D

Thanks for the link Steve McVoy, I recall seeing it a while back on your site and was looking for it again. Glad to see you involved with NBTV forums too, as you know I am a regular poster in the Videokarma forums under the same username, I have only recently gotten into the mechanical TV side of things and now scheming up fun exotic ways to present mechanical television as it is fun to do!:D

PostPosted: Sun Jul 29, 2012 10:10 pm
by Harry Dalek
Good Job troy ,nice to see this on the forum i have not seen a nipkow like this tried well worth what you are doing in casing it .

I like that it can do the horizontal and vertical systems ,with 2 driver circuits and 2 video signals your monitor could show 2 things at the same time in vertical and horizontal formats interesting very well done watching with interest.

PostPosted: Mon Jul 30, 2012 1:24 am
by aussie_bloke
Thanks Harry. Am watching your Octagon project with interest too, it's looking good!:D

For the casing, the desk drawer is part of it for the back supporting the Nipkow disc and LED banks, the front I am deciding on that, I will probably use another desk drawer as I've got quite a few of them. I plan to install two magnifying glasses in the front portion of the casing.

PostPosted: Mon Jul 30, 2012 5:08 pm
by Harry Dalek
Hi Troy

aussie_bloke wrote:Thanks Harry. Am watching your Octagon project with interest too, it's looking good!:D

No worries just finding the right pots to control the thing other than trimmers i would like mine to be multi NBTV system from the one working test i did seems 48 line would be no problem and it would be nice to 60 line but we will see.

For the casing, the desk drawer is part of it for the back supporting the Nipkow disc and LED banks, the front I am deciding on that, I will probably use another desk drawer as I've got quite a few of them. I plan to install two magnifying glasses in the front portion of the casing.

Doing well i have never tried an AC motor system i suppose they are stronger mounting nipkows .

It might be an idea to make the disk easy to attach and detach if motor direction is a problem for the horizontal system...

I like to the reusing of the desk draws i am hopeless at wood work so i too reuse the reusable ..but i have to do small for space and safe keeping .

Good build it will be great to see it running ..

PostPosted: Thu Aug 02, 2012 3:04 pm
by aussie_bloke
G'day all. Just a little update (no pics, they'll come soon), I have done a lot more work on the multistandard televisor and have got it to testing stage, the LED banks are correctly positioned and tested the 60 line horizontal scan section and started seeing a dim picture so that's a good start, unfortunately the disc came flying off due to the pulley cog on the spindle being ever so wonky and vibrating the disc. So more work to be done, will have to find a better belt cog for the spindle. Also the I found the spacing between the picture lines uneven so I didn't drill the holes accurately but precision work is not that easy of a task. Anyhow will keep working at it and will post pics of the construction work done since this post hopefully tonight.

PostPosted: Fri Aug 03, 2012 11:54 pm
by aussie_bloke
I have now fixed the pulley on spindle issue, have replaced the metal pulley cog with a plastic one which is well positioned with minimal wonkiness and the belt stays on the cog nicely and the spindle spins quite nicely with not too much rattle around the speeds necessary for 30 to 60 line scan!:D

Anyhow have been doing some proper testing for all 30/32/60 line scans with videos various set standards from Gary's Video2NBTV program of those line standards and I am successfully getting pictures!!!:D Only main issue with the pictures is the fact I didn't accurately drill the holes in the disc so the lines are unevenly spaced and finer detailed pictures don't look recognizable not even on 60 lines, but otherwise I am glad it is working and I can always get another record and devise a means of more accurately drilling the holes.

With adjusting the motor speed, I can pretty much run the sewing machine motor at around 80 to 120VAC to get the scanning speeds for 30-60 line and once again for syncing the speed I set the speed a bit over and gently brake the motor spindle like with the plywood disc televisor, this time using my finger. This actually gives me an idea of using a constant gentle break on the motor spindle and adjusting the speed with variac so when slowing the motor down it will slow immediately instead of freely spinning with momentum and gradually slowing, that way I can easily control the speed. Of course I do want to eliminate the need for a variac and use a variable speed control circuit instead.

Anyhow I have taken plenty more photos of the construction of my set, unfortunately no screen shots yet due to the fact the pictures are dim and don't pick up well on my mobile phone camera but when I do telerecordings with my super sensitive Panasonic CCD camera I will upload screen grabs for you's to see.

PostPosted: Sat Aug 04, 2012 4:57 am
by Panrock
Sorry to be a party-pooper, but these threads with huge numbers of full-sized pictures are very unwieldy to download and as the pictures appear one by one (slowly) the text I am reading is apt to jump around out of sight.

I gave up waiting for it all to download in the end.

Any chance of a more concise presentation?

Steve O

PostPosted: Sat Aug 04, 2012 6:32 am
by Dave Moll
I have the same problem. In fact, your post about it kept disappearing off the screen as I attempted to read it.

I have raised the subject in the moderators' area to discuss what possibilities there are and their implications.

PostPosted: Sat Aug 04, 2012 1:21 pm
by aussie_bloke
Hmmm. Sorry to hear you both are having troubles with viewing the posts. The best thing I can do is compress the JPG images down so they are under 100kb each with minimal loss of quality which is what I do for my website and repost them and they should load up quick and no worries.