My New Mechanical TV

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Re: My New Mechanical TV

Postby FlyMario » Wed Oct 14, 2020 9:01 pm

I am feeding the output from the Hall Effect sensor into a 74LS04 inverter to make it a positive edge when the magnets are detected.




Thanks for your comments Harry!
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Re: My New Mechanical TV

Postby Klaas Robers » Thu Oct 15, 2020 1:07 am

This looks Ok. There is some jitter on the signal, but that is not bad. An optical pick-up as well gives jitter, so why should a magnetical one give no jitter.

For synchronisation on the sync pulses 32-1 of the NBTVA video signals from CD, you might remove one of your magnets. You can try that already and see on your oscilloscope if a pulse is missed now and then.
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Re: My New Mechanical TV

Postby Andrew Davie » Thu Oct 15, 2020 1:26 am

To embed youtube links, just use the code-part of the URL -- skip the prefix/domain stuff.
That is, with the youtube tag.... put the code between the begin/end tag markers
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Re: My New Mechanical TV

Postby FlyMario » Thu Oct 15, 2020 2:15 am

Thanks Andrew. Someone must have been fixing my links then.

Klass, I think I am fine with this for now. I think that the video output will be fine but we will have to wait and see. With the Inertia of that Aluminum disk, I don't imagine any overreaction by the sync matching will do much. Thanks for your observation.
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Re: My New Mechanical TV

Postby Andrew Davie » Thu Oct 15, 2020 2:57 am

FlyMario wrote:Thanks Andrew. Someone must have been fixing my links then.


Yup :)
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Re: My New Mechanical TV

Postby Dave Moll » Thu Oct 15, 2020 5:12 am

FlyMario wrote:Someone must have been fixing my links then.


Yes, I did when I saw the word "youtube" trying to be a bbcode.
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Re: My New Mechanical TV

Postby Andrew Davie » Thu Oct 15, 2020 8:15 am

Dave Moll wrote:
FlyMario wrote:Someone must have been fixing my links then.


Yes, I did when I saw the word "youtube" trying to be a bbcode.


Um... youtube IS a bbcode!!!
Look at the shortcut buttons top of text entry.
You can replace a link to youtube with bbcode youtube and the code for the video itself.
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Re: My New Mechanical TV

Postby FlyMario » Thu Oct 15, 2020 8:43 am

Oh man... Look at this if you have time please.


youtu.be/FAXUOTKu5Zo
Hopefully I did this link right.

So here is the story. I have an Arbitrary waveform generator. I coupled both outputs so that they would have the same frequency at which I could put a frequency deviation. the stable 400hz goes into the signal pin (14) of the CD4046 and the signal I offset goes into pin 3. As you can see in the video, when I have no deviation the output is a square wave. I expected it to be flat as Klaas had described. I did put a resistor to ground on the output pin (13) and to plus 5v so that I would have (voltage divider??) what Klaas had explained.

As you can see the output is in millivolts. I almost missed that I had output at all but I finally turned the scope into the MV range. Of course I could amplify that but lordy... what in the world can someone do with that signal? It seems to me to be the strangest thing. All I did was move it up and down 1 hz. I even replaced the 4046 to see if that would fix the problem but no.

So to be clear. I put a 10k ohm resistor from +5v to the output on Pin 13. I put a 10k ohm resistor from ground to Pin 13. and measured that the output from pin 13 on channel 2 on the scope. Pin 13 is quite busy.

The signals going into Pin 3 and 14 are at 5v and Square Wave. I place a slight frequency deviation on the signal going into pin3.

For reference this Is what I am working off of with the exception of the resistors described above.
CD4046.jpg


Strange.
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Re: My New Mechanical TV

Postby FlyMario » Thu Oct 15, 2020 9:41 am

There are some things that make me feel like they are real CD4046's and other things like the output in pin 13 make me sure it is not. I got them off of amazon and the price I paid seems comparable to what I would pay mouser. If I apply voltage to the VCO

Klaas's comments to me are exactly how the datasheet explains the output. However, it is so strange that the output is in mv and the stupid triangle waveform that shifts left and right.
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Re: My New Mechanical TV

Postby FlyMario » Thu Oct 15, 2020 3:01 pm

Curious... I increased the voltage of the signals into my test circuit and suddenly everything seems to work. There must be some bias between the VCC voltage and the Input signals. The Chip getting 5vdc and the Pulses set to 7vdc and all the output seems to be functioning. Is this something about CMOS? I didn't try any other voltages. Makes me wonder if VCC was put to around 3vdc and the pulses were ttl 5v would the chip perform properly. So very strange to me.
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Re: My New Mechanical TV

Postby Harry Dalek » Thu Oct 15, 2020 4:47 pm

FlyMario wrote:There are some things that make me feel like they are real CD4046's and other things like the output in pin 13 make me sure it is not. I got them off of amazon and the price I paid seems comparable to what I would pay mouser. If I apply voltage to the VCO

Klaas's comments to me are exactly how the datasheet explains the output. However, it is so strange that the output is in mv and the stupid triangle waveform that shifts left and right.


Have you got any others peter made via some one else ,good to see even if you have to buy one from a local supplier , they ae fussy things at the best of times hard enough to get going with out the problem your explaining .
I am thinking every one is like me and uses ic sockets for problems like this good idea to do this if you haven't change the ic .
Do you have one handy from a past project ?
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.
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Re: My New Mechanical TV

Postby Dave Moll » Thu Oct 15, 2020 6:26 pm

Andrew Davie wrote:Um... youtube IS a bbcode!!!
Look at the shortcut buttons top of text entry.
You can replace a link to youtube with bbcode youtube and the code for the video itself.


Ah! As you say, putting the full URL confused the forum software, so it simply appeared as a text string rather than interpreting it, so
youtu.be/tcklZ72YWiE should work.
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Re: My New Mechanical TV

Postby Dave Moll » Thu Oct 15, 2020 6:32 pm

Please forgive my unfamiliarity with that particular function (which I've not met elsewhere). Even moderators don't know everything. :roll:
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Re: My New Mechanical TV

Postby FlyMario » Fri Oct 16, 2020 11:09 pm

Ehh... forget that PLL... It is probably way smarter than I am and judging from this forum, they are not for the faint-hearted. So no Judgement!!!!!!!!!!

I installed a PID lib for my Arduino named ... PID :)

For the reference signal, I am sending 400hz from my function generator. I am also sending the pulses from the Sync wheel (hall effect) in. Of course, the difference between the pulses is 2,500us, and with the basic settings for the PID...

setPoint = 10; Kp = 3;Ki = 2;Kd = 1; Pidmode set to AUTOMATIC

Which I stole from a basic example. https://github.com/JeremySCook/PropPID/blob/master/PID-Driver.ino

While testing with these settings, I seem to be able to keep the disk about 200us off of the video sync. I am sure that could be tweaked down with settings but I need to mount my Lamp assembly to see if it is even necessary.

I will try that tonight and this weekend I am sure. I am trying to work out how to get the line counts in sync. I can only imagine I could add the difference between the line counts to the difference between the sync pulses ... maybe the PID would speed the motor up and get those together too.

Pretty happy with the results for the hour I spent on it this morning.

More to come.
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Re: My New Mechanical TV

Postby FlyMario » Sat Oct 17, 2020 1:22 am

That seems bizarre. Why would you have a SetPoint? I would think that value should be 0 and the PID should just sync the two signals.
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