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