Composite Video high res single pixel

Using Arduino Project Guidance
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I've got a beautiful old CRT I'm planning to turn into a quantum double slit experiment, but before I clip away the electro magnets for directing the electrons I need to be generating a composite video that plots a single pixel to the screen..

I've got a little auduino nano to run the TVout demo code easy enough but the res is too poor, by the look of the 128 × 96 pixel it's double the size of the screens capabilities.. So probably a 256 × 192 resolution would be grand.

The nano hasn't got much memory I know, I've got better boards but it seems like a waste for a varably flashing single pixel and I'm not sure the TVout library's will do it anyway without tweaking currently beyond me.

Just after 1 bright little electron at a time..
Any recommendations?

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By using composite video, EVERY pixel is plotted. Perhaps you want all but one turned dark.

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Haha, good point, I'm really only after a single brightest white pixel an a lot of dark ones I suppose.

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TV use interlaced scans, so if you plot a single pixel every time fro a frame sync pulse it will be twice as high as it should be.

There for you have to count frame sync pulses and only plot on the odd one (or even one it does not matter). A quick way of checking if a number is odd or even is to simply look at the least significant bit of the number. It will be logic zero for even or logic one for odd.

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I was vaugly aware of that but would undoubtedly overlooked it so thank you,

So even if the TVout stuff worked at the right resolution it would still have required getting into the nuts an bolts of it..

I've been reading the threads on jans videoblaster with awe, been a long time since I dabbled with assembly, do you think maybe brushing up on assembler an using that code as a base may be a good start?

My C is a lot sharper, maybe if I just come to understand the composite video multiplexing well enough an start from scratch using the ordinary auduino ide I'd stand a decent chance?

I've been ruminating on the experiment since I was a child, it would mean a lot to me to finally get some solid answers,

I plan to revacumb the tube by blasting it full of carbon dioxide an putting calcium hydroxide an silica gel in it as vacumb pumps are ridiculously expensive an would be a logistical nightmare to use effectively.

Thanks again for the help.

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I can't see the point other than to make the code run faster. Does it need to be faster?

How would that work? It will not evacuate the CRT it would just fill it with gas so that electrons could not travel through it.

I used to be a lecturer in Physics at a UK University, so I know what I am talking about.

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A single pixel is far from a single little electron.

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The C02 would theoretically react with the calcium hydroxide to make calcium carbonate (I think) an water.. an the water should get sucked up by the silica gel.. tho it's only a theory atm, I'll be doing some bottle experiments in the next few days to see if it's viable.

I'll just have to learn my composite video stuff an code it from scratch it would seem.

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From what I've gathered, each electron is of such voltage that when they hit it is enough to light the pixel up.. am I wrong?

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At work we used to store electronic components in a heated/low humidity cabinet.

The silica gel desiccant only got the relative humidity down to somewhere between 5% and 10% RH. The silica gel was periodically regenerated.

I can't believe your proposed vacuum generating system will work - have you tried it?

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Atmospheric pressure is around 100kPa.
The pressure in a cathode ray tube is typically 1µPa.

Big difference.

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That is true. But to get an electron to move through such a high pressure system would require voltages akin to that producing lightning strikes. Don't try this at home.

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This will not work. You've got the chemical reactions right, but it's not going to run to a vacuum. The silica gel is an equilibrium process. I'm pretty sure the Calcium Carbonate reaction is too. That means that once the pressure gets low they'll start running in reverse. If you put loaded silica gel in a vacuum it will release moisture.

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I heard you didn't like the science you were hearing. I will add here that I'm a chemist by trade and I've build mass spectrometers for about as long as I can remember. So I actually do know a thing or two about moving charged particles around.

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@supersake Has been suspended from the forum for inappropriate language in a post in this topic and that post has been deleted

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