What you need before you can build a lasersteering is a good DAC for the signal.

Then you need a fast way to bend the laser beam in the direction of the signal. There are no none mechanical techniques available that can bend or chance the direction of light. If you find one please let me know!

If you want to project graphics with the laser steering you need to build a system that can alter the laser in the X and Y direction.

Then there are two options you can either build a system with one mirror that can do both directions or, you can build a system with two mirrors, one for each direction.

In the following section I will explain some techniques:

First of all there are two basic systems, the first one is the most simple of all and is called "open loop". This means that the position is not corrected if it's in the wrong position. This makes this technique usable for nice beam shows (tunnel effects…) but not for high detailed high speed graphics.

The second option is "closed loop". This means that the position of the mirror is measured and corrected if it is in the wrong position. A great advantage of the closed loop technique is that it can be much faster and much more precise. This makes the system usable for high speed/resolution graphics.

open loop:

open/closed loop Comparison

Piezo:

Movingcoil:
(homemade)

(general scanning)

Movingmagnet:

Piezo:
Slow but very precise (Volt/degrees) it also has a very limited maximum swing. Very usable for long-distance aiming.

Moving coil:
The name says it al, this type of galvano is build with a rotating coil inside. The advantage of a coil as moving part is that it can be build very light. This makes it very fast. BUT there's also a disadvantage; the coil is very small and it can not be cooled. So it can be fast but for a very small period.
I build one myself, (as you can see one the left side of this page) this galvano can do 120Hz square wave (open loop). That's not fast enough for graphics. And it overheats very fast (you don't want to use smoking galvano's!!)

Moving magnet:
This galvano has a rotating magnet as a rotor, the weight of the rotor is high compared with the weight of the moving coil, but there is a great advantage for the coils here, they can be very large/strong and the can be cooled. This makes the galvano even faster then the moving coil galvano. (they fasted galvano's in the world are moving magnet's and can do 60.000pps)

homebuild laserscanning

http://www.mylaserpage.de/
Subgrafix


http://elm-chan.org/

Norm and his oscillator