Re: Mechanical SSTV Steps
Posted: Fri Nov 17, 2017 10:28 am
Robonz wrote:Hi Harry, that's good advice
I made 2 watt laser scanning module which is mounted in my lounge to make a blue sky effect, also a half watt red heavily defocused on to a mirror ball. It uses the same laser polygon mirror. It looks great when I run my smoke machine. It's so powerful it will burn the wall if I let it stop. I programmed the laser to turn off if the mirror drops below a certain speed for safety. I have built quite a few laser projects in the past. I need to get a better picture for you, but you get the idea.
[url]laser_sky.jpg[/url]
And here is one of my robots with a custom camera/laser range finder. I blew a few lasers making that one. It can measure distance in stereo 400 times a second
https://www.youtube.com/watch?v=5SS7I66ut9w
Thats good Keith your familiar with lasers ....you have one up on me i have never tried one in the watt range ...your also braver than me with a laser light show these things are fun but do scare me they are one toy we NBTVer's need to be careful with ...
I would think one in the watt range full power would be too high for a SSTV it might burn the paint ...in my posts pages back there are 2 mechanical printer type SSTV's 73 magazine i think similar idea some thing that came to my attention was heat sensitive paint my daughter had a few little rulers you hold them for a bit and they change colour ...i am sure if you could paint a tin in this and had a laser powerful enough it would so the same as a UV laser on phosphorescent paint ..higher still burn a hard copied of the scan on paper ...they sort of did this with heat sensitive paper and a heated up stylus in one of those early SSTV Fax mechanical systems ...i have also seen heat sensitive sand and they have painted an image on with the sand in a glass tube .
On the scanning methods ....
I always wanted to also do this on a flat screen i tried it only with sstv with a uv led and focused it ...the scan works it was before i got the lasers the framing fly back to start position is not as neat as a rotating drum at the time as i had the led on a a dvd laser position rack doing the framing side of it up and down ..a 2 drum thin line mirror say polygon and a thicker framing mirror drum would do the same like a mechanical CRT so you could do it on the flat ...you would just have to wait a touch for the last image to defocus .
ON this also doing some research i read that a red laser would decharge the phosphorescent glow like a rubber but it never saw this effect when i tried may be the laser level something to do with it don't know ..if you still go the drum by the time it rotated back you have a clear enough screen to paint another picture any case .
I am pretty sure also that this method of a mechanical SSTV can beat the P7 CRT at least to a 12 second scan there is this in the chroma pix sstv program .