The holtzman CDM

Forum for discussion of narrow-bandwidth mechanical television

Moderators: Steve Anderson, Dave Moll, Andrew Davie

Postby Panrock » Fri Oct 28, 2011 12:45 am

Viewmaster wrote:Steve (panrock) if you are reading this how about this one heavy duty but running at 1500 RPM for your heavy mirror screw...

http://www.youtube.com/watch?v=x8M_Tpqt ... re=related

But the price is over $1500 :-(


Well actually, they seem to be doing it at a 'saving' - $251 off at the moment! Still a bit above budget. :lol:

Steve O
Panrock
Green padded cells are quite homely.
 
Posts: 835
Joined: Mon Feb 05, 2007 8:25 am
Location: Sedgeberrow, England

Postby Harry Dalek » Fri Nov 04, 2011 12:25 am

Hi even though my first stepper motor control for the unipolar motor worked i had a go at 2 other stepper motor circuit boards...out of interest as i ordered a few different type 1c's to try ...the last board i made just finished is sort of using the first idea circuit i used for the LDR monostable and a new stepper motor control using a 555 a 74194 and a uln2003 to drive the motor .

I will try and use the Lrd to electronically gear the large drum to the stepper ....

Starting to hook every thing up now to test that should be better than my last go a while back :roll:
Attachments
Picture 131.jpg
The new + old circuit remake
Picture 131.jpg (102.72 KiB) Viewed 6626 times
Picture 134.jpg
Starting to put it together now for motor control tests
Picture 134.jpg (168.74 KiB) Viewed 6626 times
Picture 135.jpg
Picture 135.jpg (171.5 KiB) Viewed 6626 times
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby Harry Dalek » Fri Nov 04, 2011 4:04 pm

Well today i started to do some tests with both drums and light still no modulation yet but i can see the potential now very much more so than the last tests weeks ago.

I can also see and relate to Holtzmans first few problems to do with the small drum ..don't really see it to the eye but when i take photos i do see theres a wobble to the drum which i think holtzman had at the start when he remade the small drum ..i think this caused hes video to be wavy...Perhaps if you read this you can let me know what you think ,i am sticking a few videos on as well...my cameras a bit old so its not seeing taking the right number of lines but does show scanning idea for the gadget,i will see if my other cameras do better on other tests.



I don't think i have the large drum rotating the right way ,got the swap the power lines around to it ..mainly hooked every thing up to see if it works together ...so speeds and such are off ..i will see this once i hook a modulated video up how far off i am.


I have to point out the stepper is free running taking the light braker from large drum line slits causes the monostable signal irregularities in the pulse ...i wanted to try this may still do and feed the pulse to pin 5 of my free running Astable and see if it will lock in ..if not i will try a few other ideas .

Its interesting seeing the line rate increase with speed differences between the 2 drums ...i wish i was better at constructing these things or i would be able to use higher speeds ...which is hard on a drum on the vertical ,you don't have to have constructed it much off to start to get it shaking ....i think a horizontal drum would be a lot easier at higher speeds.

So anyway a little closer :)
Attachments
Picture 597.jpg
Picture 597.jpg (88.92 KiB) Viewed 6605 times
Picture 616.jpg
Picture 616.jpg (92.67 KiB) Viewed 6605 times
Picture 603.jpg
Picture 603.jpg (156.6 KiB) Viewed 6605 times
Picture 611.jpg
Picture 611.jpg (94.06 KiB) Viewed 6605 times
Picture 623.avi
(4.25 MiB) Downloaded 400 times
Picture 622.avi
(3.16 MiB) Downloaded 393 times
Picture 627.avi
(3.36 MiB) Downloaded 389 times
Picture 594.avi
The best one for start up
(5.35 MiB) Downloaded 400 times
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby Harry Dalek » Sat Nov 05, 2011 12:46 am

I did a modulation test managed to show stuff on manual control ...The video i think is inverted and upside down ...i do have the problem Holtzman
was taking about when he did hes on the wavy horizontal ..and the thing does shake a bit so a few more problems to work out .

I tried to take a video tonight but the video camera needs setting up for light levels looked alright in the view finder but very grainy as a video file .

Well a incentive to go on i'll do a video again or photos when i can ....
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Wobble

Postby holtzman » Sat Nov 05, 2011 8:21 am

Hey there and congratulations for your work, it seems to be a sucsess!
There are still things I do not understand - monostable etc. - thus I have a question.
Is it possible with your system to make a test for sync between 2 drums by just rotating the large one by hand? Or you need a high speed in order to get in sync with the multivibrator? I am able to check the sync at low speed, so it's possible to know if there is 1:12 lock of my drums' speed. Are you sure yours are locked with 1:12 ratio?

Regarding the wobble problem. I once remade the small drum not because it was faulty, but because I had to find out the reason of wavy HORIZONTAL lines. It turned out to be competely the LARGE drum's problem, so I added weight at right places and balanced it. Your problem seems to be in the excentric and wobbly small drum. This causes the whole image to move left-right and/or to tilt left/right. And it is not easy to make a well-centered wobble-free drum connected to a stepper.

Image upside-down, or mirrored image: flip the direction of either of your drums' rotation.

Best luck,
Maksim
holtzman
Just nod and pretend you understand me
 
Posts: 215
Joined: Wed Apr 22, 2009 7:54 pm
Location: Jerusalem, Israel

Re: Wobble

Postby Harry Dalek » Sat Nov 05, 2011 3:15 pm

holtzman wrote:Hey there and congratulations for your work, it seems to be a sucsess!
There are still things I do not understand - monostable etc. - thus I have a question.
Is it possible with your system to make a test for sync between 2 drums by just rotating the large one by hand? Or you need a high speed in order to get in sync with the multivibrator? I am able to check the sync at low speed, so it's possible to know if there is 1:12 lock of my drums' speed. Are you sure yours are locked with 1:12 ratio?

Regarding the wobble problem. I once remade the small drum not because it was faulty, but because I had to find out the reason of wavy HORIZONTAL lines. It turned out to be competely the LARGE drum's problem, so I added weight at right places and balanced it. Your problem seems to be in the excentric and wobbly small drum. This causes the whole image to move left-right and/or to tilt left/right. And it is not easy to make a well-centered wobble-free drum connected to a stepper.

Image upside-down, or mirrored image: flip the direction of either of your drums' rotation.

Best luck,
Maksim



Hi Maksim

Yes i can see i can improve on what i have made and copied from you model which for me made it work the idea for a start!!! ...what works what doesn't is a bit easier now .

The image is wavy not great but something to work with .

I will more than likely remake the large drum in time and balance it better.

On the Monostable side of things i just want this to be using the large drum roatating and the light braker to just be a mechanical astable ..the clock for the 74194 shift register this gives the 4 pulses to feed to the unipolar stepper motor driver ic ULN2003 then drive the motor....

When i was putting it together yesterday i was thinking of just using the large drums slits or part of them and taping off parts depending on speed control ... but i found because the large drum is a bit wobberly when spinning is causes the pulse signal to vary so the motor is jerky due to the pulses changing...i am thinking of just feeding this to my 555 timer astable multivibrator and seeing if it will lock in ..the idea is tv sstv what ever deals with poor sync missing sync and it works...there are ways to deal with this .

But anyway only reason i have that problem is i used that part of the drum if i use the back or the back disk drill hole or connect up a light braker there should work better...

Syncing them slow with a monostable well i think yes ....but i ended up testing it with it both motors free running ...the stepper is pretty much drift free once set and you just have to get the large drum to speed...i was not expecting to see any thing in sync till i got it working with the monostable but it was pretty easy ..the picture is upside down and bit wavy on the horizontal so you can get this thing going on manual only control...

Last night just before i did the tests my power supply died but i had a spare i use for indoor work when the kids have gone to bed that came in handy !

My goal is to get it to lock at the 1 12 ratio but at the moment i still have to work on that ..i am doing it by eye and manual control and my timer clock is taking care of half the work...

Yes connecting the small drum to the stepper i had was a pain ..due to the small area ...i won 10 steppers off ebay last week and got them one has a nice disc one end i think i might replace the motor with this one it would work a lot smoother easier to connect and such .

Yes the image is upside down glad to hear you think i just need to change drum direction ...i was thinking i had mine going the wrong way...its funny how the brain works seeing something upside down ...i was using the NBTV test pattern i was thinking it was flipped left right but after videoing i could see it was upside down....

I will try and do some tests tonight again and see if those videos turn out better with my .. wifes camera
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby Harry Dalek » Sun Nov 06, 2011 12:38 am

Heres some stuff i took tonight not a great pictures did my best with the camera ,i can improve on the monitor as you see needs a bit of work still but ok for a 2 drum manual control.

Theres a wave to a horizontal line and theres a roll to the picture at times the stepper was clogging today a bit and a bit lower speed than i wanted ..

Anyway best i can do today i will work onit more need a lot of work to get any where near Holtzmans nice Hot rod !
Attachments
Picture 758.jpg
Picture 758.jpg (121 KiB) Viewed 6531 times
Picture 769.jpg
Picture 769.jpg (124.89 KiB) Viewed 6531 times
Picture 783.jpg
Baird head ...pictures rolling
Picture 783.jpg (100.56 KiB) Viewed 6531 times
jlb1_170.jpg
This is the photo being displayed from steves nbtv test card
jlb1_170.jpg (26.74 KiB) Viewed 6531 times
bbb.avi
with modulation
(2.7 MiB) Downloaded 391 times
dfdd.avi
(3.85 MiB) Downloaded 368 times
Last edited by Harry Dalek on Sun Nov 06, 2011 8:10 am, 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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby holtzman » Sun Nov 06, 2011 7:56 am

What i think is happening - you don't get the right (doubled) speed of 1500 rpm for the main drum. There is a picture, but half the size.
And yes, the large drum seems to sit off-centre or wobble in any way too much...
holtzman
Just nod and pretend you understand me
 
Posts: 215
Joined: Wed Apr 22, 2009 7:54 pm
Location: Jerusalem, Israel

Postby Harry Dalek » Sun Nov 06, 2011 8:17 am

holtzman wrote:What i think is happening - you don't get the right (doubled) speed of 1500 rpm for the main drum. There is a picture, but half the size.
And yes, the large drum seems to sit off-centre or wobble in any way too much...


Hi Yes i expected the speed is off ,i have to redo the main drum and the wobble also from the little drum i also expect is causeing the horizontal lines to be wavy...

I know the problems for it ( me really poor construction ! ) i will be a little more fussy fixing the 2 drums .

The Wobble on the main drum stops me going too fast as i start to get vibration, i'll just have to make another and more than likly use the other stepper i talked about ...i really like this monitor idea gives a nice picture size .

Thanks for the advice i will work onit !
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby Harry Dalek » Fri Nov 11, 2011 12:37 pm

I have replaced my large drum with a smaller one and dropped the slit size and it has of cause dropped the light levels heaps can not really see to much difference apart from the lines are straighter..i have kept my original the little drum for now for testing got the balance right now with it both really.
I wanted to increase the definition ,but need higher light levels with this size slit.

The new drum i have the slits adjusted via paper again but inside the drum this time to protect it .

Might be time to try the laser with out lenes out soon as an experiment .

Just did some tests mainly with the large drum i didn't even bother adjusting the little one yet just wanted to see how fast it would go and its pretty good now.

The picture rolls in the video sorry still on manual control hard to fine tune the speed when videoing very low def still nothing impressive yet .

I will have to work out my electronic gearing via this drum soon i know the little drum speed is off and i am getting a picture when i adjust the large to what ever speed the small one is running at higher definition pictures closer i get the the true speed .

I think counting the lines on one of the photos looks line around 16 lines.


One other thing about the F. H. Haskell's Cylinder Scanning System from 1931 (Newsletter V 9/3),he used A and B disc's drums same number of slots ...is the number that important as would you not just have to adjust speed to number of slots your system has and less higher picture size and faster drum speeds or visa versa?
Attachments
14Ldrum.avi
This is the new drum i am testing
(5.58 MiB) Downloaded 399 times
Picture 1265.jpg
Heres the baird head video again on this drum
Picture 1265.jpg (143.04 KiB) Viewed 6439 times
Picture 1261.jpg
Picture 1261.jpg (123.58 KiB) Viewed 6431 times
newdrumvideo.avi
Just showing the new drum looks cleaner than the old one bit more compact ; )
(6.16 MiB) Downloaded 393 times
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby Harry Dalek » Fri Nov 11, 2011 11:40 pm

Tonights experiment with the drums were the 1500 rpm speed and it sure gives the quality i was missing you were right there Maksim!.

Redoing the Baird video turned a crude drawing like i was projecting so to me looked photo like a lot better now .

Hell to sync on manual let alone take pictures ,my luxeons are still also running well below what they can do while modulating as i have not got that part of it right yet .

Again i tried to take photos but at that speed my cameras shutter is to slow on those light levels so it was worse even for the video the light levels were to low ...nothing i took worked

So i am there with the Quality ,once i bump up the luxeons i will try again .
Another little step tonight.
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby Harry Dalek » Sun Nov 13, 2011 11:16 pm

Well i have been working on the new luxeon driver and after a bit of fault finding (unconnected ground on part of the circuit ) i have got it going it will drive the luxeons fully ,its really just the club circuit apart from i am using a NPN tranny instead of a mosfet ..Oh and i am using 3 CA3140s didn't have a
CA3240 so improvised.
I was going to try a Uln2003 stepper motor ic as you can drive leds with it too but the transistor works fine so thats for another time ,it would be good for colour led driver experiments .
Seems to modulate fine ,i am going to test it on the drums this week and should have enough light now similar to Maksims beauty ...
Have a rest tonight few hours of soldering is enough for today and its good when it works for a change :wink:
Stay turned it might still be a rolling picture but a good one this 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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby Harry Dalek » Tue Nov 15, 2011 12:18 am

Hi i just did a quick test to night to see how the new modulation circuit works with the drum ..almost there i just have to drop the resistor values to the luxeons ..but i can take photos ..my little camera that does the videos the battery died tonight so no video yet sorry.
I need a video inverter for this every thing is back the front light wise ...

Rather boring photos sorry just did some test patterns eye of the world came out best .

But again a little closer :wink:
Attachments
Picture 1535.jpg
A women
Picture 1535.jpg (88.84 KiB) Viewed 6323 times
Picture 1547.jpg
eye of the world
Picture 1547.jpg (108.63 KiB) Viewed 6323 times
Picture 1548.jpg
Picture 1548.jpg (90.79 KiB) Viewed 6323 times
Picture 1551.jpg
Picture 1551.jpg (184 KiB) Viewed 6323 times
Picture 1552.jpg
Picture 1552.jpg (234.37 KiB) Viewed 6323 times
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Postby gary » Tue Nov 15, 2011 11:29 am

harry dalek wrote:I need a video inverter for this every thing is back the front light wise ...


What are you using as a video source Harry?

If a PC then you can use TBP to play out of the sound card and set the "Invert Signal" option. Not a permanent solution but useful for testing.

Anyway, that is all looking good. Well done.
Perfecting an NBTV system is like trying to slam a revolving door...
User avatar
gary
"Fester! Don't do that to 'Thing'"
 
Posts: 2303
Joined: Sat Jan 27, 2007 11:29 am
Location: Bundanoon, Australia

Postby Harry Dalek » Tue Nov 15, 2011 4:04 pm

gary wrote:
harry dalek wrote:I need a video inverter for this every thing is back the front light wise ...


What are you using as a video source Harry?

If a PC then you can use TBP to play out of the sound card and set the "Invert Signal" option. Not a permanent solution but useful for testing.

Anyway, that is all looking good. Well done.


Hi Gary

Yes i am using the PC wav files for testing ,one of the NBTV test cards,i didn't have the problem with the pwm modulator i was using .

Thats useful to know i never knew you could do that i will try it next time i do a test .

When i first made this thing the main drum motor is running off 12v just a LM317 to do speed adjustments ,it was just short of letting the drum run at 1500rpm or if it is i will explain so i have to ditch the PC power supply and make my own ..

I have been naughty and tried something different to the original drum i have 14 line slits not 12 i made it for testing as i was going to make a few different ones to experiment this one seemed to work right away ...so i am not really sure if the speed is still the same ....mmm i was thinking this if it really does mater that much to the number of slits if it just means adjusting the speed more or less to your drums slit number .

The aspect ratio is more likly 4.3 like i was expecting this with the smaller drum but gives a nice picture size .....

To those interested on the small drum its really going top speed of this stepper motor before it clogs but once set at that speed i really don't have to do a thing ,all i have to do is get the main drum to right speed .

Yes Gary getting there just a bit more light and what ever i want to do next really syncing would be good. :wink:
Attachments
Picture 1621.jpg
Picture 1621.jpg (176.74 KiB) Viewed 6285 times
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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4112
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

PreviousNext

Return to Mechanical NBTV

Who is online

Users browsing this forum: No registered users and 3 guests

cron