Peter Yanczer mechanical kit - Page 3 - Videokarma.org TV - Video

old_tv_nut · #31 10-01-2022, 05:24 PM

Quote:

Originally Posted by Notimetolooz

Could you explain what you meant a bit more.

The light would actually vary at 120Hz for a lamp using 60 Hz since the lamps conducts in both polarity directions of the AC line.

He isn't necessarily using CFLs.

I meant exactly what you say. In 60hz countries the lowest flash rate of a lamp is 120 Hz

rld-tv01 · #32 10-01-2022, 05:53 PM

jhalphen,

Both Dave A and I built Camera / Receiver kits which worked 15 years ago. Mine sat in Storage for 8 years after I moved from Virginia to California. Dave also hasn't used his. I pulled my kit out of storage since Dave was having problems with his. It now seems both his and mine aren't functioning properly. I don't have access to the light I used 15 years ago which was a generic Home Depot aluminum shield clamp work light. I have two 85 watt effective 700 watt photographic lights in storage. I have to go fetch one or both in the future for another test of mine.
What Peter's instructions need is a trouble shooting section. Both Dave's and my kits are fully built and worked fine 15 years ago. I was probably lucky at the time. Two weeks ago I made the mistake taking off the camera disk and putting it back on with the rubber gromlet washer holding the disk too close to the hub behind it. Reading Peter's instructions again I saw it states the disk must float freely on the spindle. Peters instructions shows everything you need to build the camera / receiver but very little on how to trouble shoot (a little bit on page 9 only).

Notimetolooz · #33 10-01-2022, 10:06 PM

What I was driving at was that 15 years or so ago LED lights, etc. were not as common as now.
The frame rate is 30 per second, i.e., 30 Hz. With 24 lines the line rate is 720Hz.
The highest video frequency would be difficult to know, however the image is approximately square so if it could resolve along each line at the resolution of the vertical scan (24 "dots") that would give a upper video frequency of 17,280Hz. That would be a video bandwidth of 30 Hz to 17KHz, all within the audio range. That range includes the 120Hz flicker rate.
Anyway it was just a suggestion for the source of the problem.

The camera kit instructions don't go into details about the receiver as far as I saw.

EDIT: As my head hit the pillow last night I realized I made a calculation mistake. The upper video frequency to give a 24 "dot" resolution on the lines is half what I wrote, 8,640Hz not 17,280. It doesn't matter for the problem here however.

rld-tv01 · #34 10-04-2022, 01:20 PM

I picked up the two 85 watt effective 700 watt photographic lights from storage. I'll do another test with them soon.

Ref:sync besides the receiver control knob to start stop the disk I found out years ago I could use the eraser end of a pencil to momentarily slow the receiver disk. You have to just lightly touch the disk avoiding the ends of the metal springs sticking through from the other side. The disks are constructed of mylar plastic similar to computer floppy disks. I wouldn't try this on aluminum disks. Years ago I thought about using some 8 inch floppy disks from vintage computer network equipment (i.e.COM10, IBM network controller etc) for constructing mechanical TV disks.

rld-tv01 · #35 10-05-2022, 05:34 PM

I did a test with one of the photographic lights. Pretty much the same results as before. The light has a on/off switch which when flipped changed the receiver screen somewhat. I tested again with the more portable light with 20 LEDs in a grid pointed directed at the camera lens and it gets a multiple light spots on the receiver. I have a very tight space to test in. (so many things in the room: radios, TVs, computer printers, tower computer, CNC router machine etc) I turned the camera and receiver positions so on my next test I can have better control adjusting the distance of the test subject.

rld-tv01 · #36 10-08-2022, 12:38 PM

As Dave and I seem to have the same problems / operational peculiarities I was wondering if the "3m super 77 spray adhesive" we used to fasten the aluminum foil mau have reached end of life? I am a retired computer software engineer and back in the 1980s I was on a contract with the LA department of Water and Power. They found out the Glue they used on PVC pipes had a life span of 10 years and they needed help on a computer program managing pipe replacement in the entire city of LA. I built my camera 15-20 years ago and wonder if the adhesive may be contributing to the problem.
At this point I think a partial rebuild in instore. The 3m spray adhesive is $6.50 at home depot. While I got the P.E. tube off I can realign the lens optics and unsolder/resolder old solder connections. With other project I'll have to work on this a little at a time.

BTW, I have a 2nd different Mechanical Kit from Peter Yanczer. It consists of two aluminum disks with laser cut holes, two motors and a set of disk hubs. It is in a box in storage never built. This mechanical camera / receiver corisponds to his book and his early television newletters. I also have a Western Visionette from 1932 sitting here on the shelf at home. I had hope of building that Yanczer kit and eventually using that camera to drive the Visionette.

rld-tv01 · #37 10-08-2022, 07:28 PM

I was wondering why Peter used an aluminum foil wrapped cardboard tube for the kit and it seems an aluminum tube for his camera design in his mechanics of television book? My camera from his kit on the left photo. His camera from book on right.

Dave A · #38 10-08-2022, 09:04 PM

I am thinking that the foil is just like a tube shield over the PE. Protect the underlaying device. The glue underneath should have no effect if the foil is continuity connected across the units..

Notimetolooz · #39 10-09-2022, 10:01 AM

I would think that the use of foil over the solid aluminum tube was a cost cutting choice.

Out of all the kits Peter sold maybe half of them were ever built I bet.
Of the ones that were built not all of them were ever gotten to work correctly.
Most of the working ones are stored someplace inconvenient to access for the purpose of comparing to yours.

I think there should be some way of determining if the problem is in the light sensor and lamp electronics or the synchronization system.
I think it would be very useful if you looked at the signal from the camera with an oscilloscope while using a simple pattern in front of the lens.
Something like a card with the top half white and a bottom half black.
Since there is no blanking signal, if you displayed an entire frame on the scope you should see something like a squarewave at 30Hz.
Seems to me that if you described the image as garbled that the problem is with synchronization.

rld-tv01 · #40 10-12-2022, 06:27 PM

A slight excursion from the specifics of Peter Yanczer's camera/receive design to a deep dive into generic mechanical TV principles, design, software and tools including source code for 30 line and 60 line for Linux

I found the following website doing a google mechanical tv keyword search

https://sourceforge.net/projects/nbtv-design-tools/

specifically downloads half way down on page

Released /nbtv-tools-and-doc-V1-4.zip

As specified on the website - not everything is applicable to every design; use as needed, wanted etc.

Dave A · #41 10-17-2022, 05:17 PM

Back at it and success!

I set the pair up to shoot a homemade "Test A" I created. The camera came up fine judging by a clean motor sound. The receiver did not. Some hints of intermittant scraping as it was tilted or bumped. I opened it and saw that the upper part of the disc was touching the LED port cover by the felt standoffs. I could see where it was scraping on the lower left corner and the back of the disc showed the same scrape. Look for the lighting bolt like scrape on the lower left corner of the opening on a piece of tape. Just enough to vary the speed occasionally. It is a Peter design full of electrical tape and the opaque filter over the LED's. And the filter shows some white dots that may be of a decay of some sort.

The LED mask assembly has warped over the years and is protruding just enough to touch the disc beyond the felt.

I moved the disc off the mount to get to the motor mounts and took the two full washers from the bottom back of the mount and moved them ahead of the motor flange to give a small tilt forward at the top of the disc. Just enough to clear and be stable.

I also tested my earlier hand-capictance observation. It seems to not be a factor in this new version of the tests.

With room light it was still garbage. Then I used my 8mm light bar for maximum light. It worked. Vertical sync (the only sync you can get) was touch and go. The pic is a bit off but I was a one-armed-paperhanger holding the lamp and a camera. I am not sure if the camera can really do a grey scale pic after all these years. The contrast and brightness controls seemed to do their functions. LIghting is a big factor. That test is for another day.

Turn pics 2 and three CW. I sent them proper and they did not make it here

Go Phils 2022.

old_tv_nut · #42 10-17-2022, 06:30 PM

Hurray!

rld-tv01 · #43 10-17-2022, 07:24 PM

Congratulations!

Notimetolooz · #44 10-18-2022, 08:37 AM

Good news!
Glad you finally got some results.
I wouldn't be surprised that the "video" chain isn't very linear. For one thing I think the light output of a LED depends on the current through rather than voltage across it.
There might be a similar relation with the phototransistor.

Dave A · #45 10-27-2022, 06:47 PM

A minor update.

I had a stuck lens and worked it out tonight. I think the paper-on-paper tube glide had fused a bit from age. It was just not moving so I just patiently sat there and rocked it and rocked the assembly right off the body. That actually helped as then I could stress just the lens assembly. Remounting later is good.

It only has 7/8" of travel from far focus (lens in) to near focus (lens out). About a 2-4' viewing distance overall per the build instructions. The trick is to focus on the disc holes, not the PE.
Probably not good for exciting views of my back yard.

Eventually I got it to slide straight but still not able to turn. I then candle waxed each open end and kept exercising and adding more candle rubbings. A bit of cardboard powder exited. "Slowly we turn, inch by inch". Success and now it turns freely.

The lens is curently loose so that is a re-glue and then the whole assembly remounts to the cabinet. Bit by bit. Thanks to Jerome/ETF for the complete .pdf assembly instructions. And in the .pdf is the schematic for the camera amp on page 25. Jump in with what you think it is. The receiver .pdf is yet to be found.