UPDATE: I will be unable to post the programming video because of a few problems getting video from the camera onto the computer. I'll see if I can get it fixed.
To build this plotter you will need the Lego robotics invention system with few extra parts and a laser. It's too complex to describe with just words so look at the pictures and descriptions. High powered lasers can be purchased at Wicked lasers. If you are interested in learning about high powered lasers go to Laser forums
General description: The robot can move along two axis and turn a laser on and off. The X axis is controlled by a rack and pinion that move very slowly. The Y axis is controlled by a slow turning axle that pulls a string connected to the rack and pinion assembly. Each of the axis has a touch sensor that is pressed about every millimeter. This makes the robot very precise because it knows where it is at all times. The action used to turn the laser on and off is simple but very efficient. It slides a small part over the button on the laser. This part is constantly being pushed against the laser with rubber bands. Thus it can simply slide on and off the button without the motor having to run constantly to hold the button down. I only have a 15 milliwat laser so I have to focus it. I used a small plastic tube that is about the same diameter of the laser. At the end of the tube is a small convex lens I took out of an old gun sight. This is all attached to the end of the laser with electrical tape.
I have uploaded some files and software to view in 3D. The software will install MLcad and LDview. After you have the software installed, open LDview and it should ask what files you want to open. save all of the files I have posted to one folder and open them one at a time. The file named laser plotter is the whole assembly. I recommend looking at each part individually to build them then using the laser plotter file to see how they are put together.
Posted by Laser Community member: CaptainCrash
Step 1: Base, Y Axis
The method for building I used is rather easy to look at and figure out. The longer black beams are spaced apart by two layers of flat parts this makes it very strong and spaces them the right distance so that vertical beams can be added. A lot of gears are used in this assembly because it has to go slow enough to give the laser time to burn.
Step 2: Rack and Pinion, X Axis
This is very fun to make because of how this part works. The gears make their way to the bottom of the assembly and touch the beams at the bottom that have teeth on them. On side of this assembly has wheals on it so when it has to move along the y axis it moves evenly.
Step 3: The Laser Mount
This was the hardest to design but it works very well. There is one arm on each side that move up and down to activate the laser. A small piece is slid over the button holding it down without constant motor activity. The laser I used is the Executive Classic that can be found here. The model that I received is a bit over powered so I recommend using the 35 mw. The lens I used to focus the laser was from an old gun sight that is attached to the laser with some electrical tape.