For my next 3D Scanning / Printing project, I am building a home-made laser scanner. The inexpensive ones cost around $1500, and I really think that the underlying principle of operation is simple, so I am going to just go for it.
What is required is a rotating platform, one or two line lasers, a camera, and some image processing. Imagine a line laser aligned on the center of a rotating platform. If there were a thin cylinder at the platform center, a camera would just record a straight line. Put a complicated object on the platform, and the laser line will distort based on the object shape. If a computer controls both the platform rotation and camera activation, each distorted line will be associated with a particular angle of rotation. Collect X and Y for every point on the laser line, and then map them in to space at the recorded angle. At the end of the process, you will have a point cloud. Several free programs will map point clouds in to meshes. I am guessing that this part will be kind of tricky, but hopefully manageable.
What I can do pretty easily is build up the mechanical parts. So far I built a rotating platform controlled through a stepper motor controller commanded by an Arduino running a simple program.
Here are two videos showing my progress so far.
One trick that I figured out in this exercise was that although my laser cutter (only 40 Watts) can not burn through birchwood, I can definitely mark the surface of just about anything for cutting with other tools. This is very effective compared to any alternative. The accuracy is of course perfect, and the process is really fast since I am not trying to burn through anything. I also don’t need to try too hard to be right at the perfect focal length from the final lens. Here are images of this process used to make my rotating platform.