I had an idea to hookup a laser pointer to a couple of servos to write messages on walls. But my guess is that the servos will not be able to move fast enough. Is m assumption correct?

Eventually I want to build a full laser projector but wanted to start off with a simpler project for starters.

 

You may want to look at LASER Holograms. From simple kits to really surreal stuff out there, A Google of LASER Holograms gets started with some small stuff and then you work into incredible stuff like:
Elvis Presley & Celine Dion duet : 1968 - 2009
Elvis is a hologram, assembled with LASER. I am not sure how the LASER projection works. My brother who is a Theater and Arts professor works these things with an old friend of his in Cleveland, Kid's name is Joel and his company is called Event Works. Not sure how it all fits together but know it is expensive and material setup is critical. There are some pretty inexpensive basic kits out there relatively inexpensive to play with on a small scale.

Ron

 

I don't know the current speeds, but we had set up a laser raster scanning system from scratch. The heart of the system was two mirror galvanometers for deflection, two function generators and a storage medical scope. Old school, but it did work. We did interface it to a computer to get x-y-x data. The control box, handled blanking, line and x/y scan and the Z modulation mode (intensity or Y modulated).

Most of our scans were small area, but we did scan a large area a few times.

 

Here's a home built project .

 

Here's a home built project .

Yes I know about this project.

Again I am not looking to build a full projector. That is a bit ambitious right now. I just want to know if it is possible to simply point a laser pen at a nearby wall. Control it with a couple of stepper motors to write some simple text on the wall.

My guess is that the steppers won't be able to move fast enough to draw anything of appreciable size where your eye will see interruptions in the beam but I might be wrong.

The software controlling the hardware I can all work that out. I just want to know if it would work or not.

 

Steppers/servos would be too slow.
I'd try mounting small mirrors on a couple of stripped-down loudspeaker/headphone cones/diaphragms. Might need some light-weight levers to amplify the movement.

 

It's done with mirrors.

 

I dissected a laser printer a while ago and found some neat optics inside.
I thought if you aim 9 of these lasers Mini LASER Head, 635nm, <5mw vertically, at the rotating mirror you could project a line of text on a wall. But the quality would only be like an old 9 pin dot matrix printer.



This is interesting.



In a conversation at a Maker Space, I found out about this
http://www.explainthatstuff.com/projectiontv.html
DLP® projectors
Even LCD projectors are looking old-hat now. The latest TV projection technology, DLP® (digital light processing), uses an entirely different method of making images using microscopic mirrors.
Have you ever used a mirror to send a light signal to a friend some distance away? The basic idea is simple: you angle the mirror so it catches light, then tilt it slightly so the light travels where you want it to go. By tilting the mirror back and forth, you can send precise light pulses of either long or short duration—and transmit complex messages using something like Morse code. The latest projection TV system, called DLP® (digital light processing)technology, works in almost exactly the same way.
What is DLP® technology?
Developed in 1987 by Texas Instruments scientist Dr Larry J. Hornbeck, DLP technology is based on an amazingly clever microchip called a digital micromirror device (DMD). A DMD chip contains about two million tiny mirrors arranged in a square grid. Each mirror is less than one fifth the diameter of a human hair, and it's mounted on a microscopic hinge so it can tilt either one way or another. A bright lamp shines onto the DMD mirror chip and an electronic circuit makes the mirrors tilt back and forth. If a mirror tilts toward the lamp, it catches the light and reflects it off toward the screen, creating a single bright dot of light (equivalent to a pixel of light made by a normal TV); if a mirror tilts away from the light source, it can't catch any light, so it makes a dark pixel on the screen instead. Each mirror is separately controlled by an electronic switch so, working together, the two million mirrors can build up a high-resolution image from two million light or dark dots.
To make color images, DLP projectors need an extra bit of technology: they have a spinning colored wheel inserted into the light path, which can color the pixels red, blue, or green. Combined with the tilting mirrors, the color wheel makes a front-projected TV picture from millions of pixels of every possible color.