A machine that draws with light

[keebler303]

It might take a bit of specialized software to generate the code, but I would think it would be much easier and cheaper and maybe cooler if the light source were mounted on a turret with 2 rotational axes. Much like an army tank. The distance and angle would define the length of the lines. This design would have low low inertia and would be very clean as the light source could be mounted on the ceiling and pointed at a phosphorescent wall.

Matt

[Cerberus]

Hi,
It would be easier to use a 2-galvo style device, like those used on laser projection. You just need a couple of mirrors and steppers, or servos, and a bit of math. And it would be faster

[keebler303]

yes, that is what I was describing.



Matt

[vger]

I recently saw a "Sand Plotter" at a local college Engineering building. It ran on stepper motors and one of the professors there said she had it moved away from the wall adjacent to her office due to the noise it generated. The accel / decel and step impulses would sing through the board and cover panels.
Here is a link to a video of a similar machine:
http://193.135.56.86/snowflake/techn...technorama.wmv
And another link: http://taomc.com/

Artzofacto, if you are not set on using the skateboards, I have a suggestion. Suppose the flashlight were suspended above the table with small steel cable in loops similar to the maner some copy machines move the mirror/lamp asembly. With proper isolation of the cable pullys you could run power to the led through the cable. You wouldn't even need to put the flashlight itself out there, just the LED. If you are interested in the cable idea let me know and I'll try a drawing of the idea. I'm in Tulsa and would like to see the result one day.

I recall many years ago having some phospoescent paint that was a light cream color under normal light and glowed light blue in the dark. A friend used some to put stars on his bedroom ceiling. Was really amazing when you turned off the room light at night.

Till next time
Steve

[Stepper Monkey]

Couple of obsevations;

First, it would seem that with collimated LED's you would have roughly the same sized spot and watt-density delivered to the table whether it was a few inches or a few feet from the surface. There just isn't that much dispersion over that distance. Why not mount the light up off the table several feet?

Secondly, to get the speeds you are talking about, it would seem easier to use steppers to effect angular motion to the flashlight instead of moving it the whole length of the table were you to keep the flashlight perpendicular. If you were to simply tilt the flashlight, it would allow for VERY small motors to move the light as quickly as you wanted as an inch of angular movement of the end of the flashlight would effect a movement of the projected spot of light by several feet across the table surface. The incident angle of the light would not be relevant to what you are trying to do, correct?
Tilting isn't as trick or as fast as two mirrors of course, but way cheaper, simpler, and less technical with the math. Tilting probably is still easily capable of faster speeds than are needed here anyway.

Thirdly, with this approach you have no moving parts near childrens hands, and possibly no moving parts visible at all. Shapes just appear on the table - Magic!

Fourth, Size is no longer a limitation of physical axis length. Size is effectively unlimited. Also, as Keebler pointed out, with this setup a wall would be just as valid of a canvas as a table, which would just be cool.

[zenstatez]

I think you should give a quick search on google for both the "blu-ray phaser" as well as "blu-ray laser glow in the dark" the phaser has instructions on instructables and can be built for around $100 i think the effect in your machine would be amazing... just throwing it out there

[zenstatez]

actually.. if it was the route you were to look into... after reading a bit more about it i'd have to recomend going to laserpointerforums and checking it out... they have all the real info on how to hook up the lasers properly.... either way... blu-ray laser drawing in glow-in-the-dark paint on a skateboard cnc... that would be incredible

[IanRogers]

I only skimmed this thread, but the first thing I thought of when I read the description was this :

http://muonics.net/blog/index.php?postid=15

If nothing else it's a damned interesting read.

Enjoy.