A ploter described here writes on dark plastic things with a DVD-RW laser diode. I did not made the mechanism with stepper motors which you can see on the photos below, I got it whole as it is and I don't know where it comes from. With a complete and working moving table I had to build a driver for it. There was two solutions: make a simple transistor buffer to connect motors coils directly to LPT port and write a control program for my own, or make more complicated motor drivers with step/dir inputs and use one of commercial control programs, for example Mach2. I choosed the first solution, it was faster for me to write a simple program than to build complex motor drivers :) Electronic part of this project isn't even worth drawing a schematic, becouse it's only nine NPN transistors: eight to drive the motors and one for turning laser on and off.
Here are screenshots of my control programs:
The left one converts monochromatic bitmap to a text file with coordinates of following ploter moves. The right one uses this text file and controls the table motors thru the LPT port. These programs are sufficient for drawing a simple graphic or text but if I'd like to play with it longer I'll probably have to build these more complicated motor drivers and use a better program :)
On the photos below you can see laser burning an a black chip card. On the right photo an extremely complicated and technical advanced focusing system made of LEGO bricks :P
Below the whole ploter and a precision and burning depth test. Both tests were done on a CD case.
This moving table is very precise (200 motor steps for 1mm move), but work area is only 55x55mm and it moves very slow (max 1mm/2s). It would be great to have a bigger ploter, but this tiny one is cool too :)
Below the best material for burning I found laying around. It's a chip card made of white plastic covered with black paint. Laser burns thru the paint and undercovers white plastic so lines are very well visible. Unfortunately, 'pl' in burned webaddress failed a bit, becouse I was taking a photo and touched the laser with camera lens when it was burning ;P
Below a black plastic telephone card. The text is not so clear like on the photo above, however it still looks good. As you can see, burning on this card was creating quite a large amount of smoke. In such cases (amount of smoke depends on the material) it's necessary to use a fan to blow the smoke away. Without fan the smoke is blocking laser beam and burned lines are not regular.
This laser can easily burn thru thin black foil, you can see it on the right photo below - it's my nickname cutted of a magnetic foil from a floppy disk.
With this ploter I can make cool signatures on many things :D Below two logos burned on my dads and brothers mobile phones. Unfortunately my phone has a silver panel so I can't burn anything on it :(
Below two films shows this ploter during work. On the first film the laser is not moving and the burning object is laying on the ploter table. On the second film the laser is attached to moving table - it is the improved version. And it burns on wood! :D
Update 20.10.2007 :
Becouse of many questions about construction of my moving table I'm putting here some thorough photos of it. I also drew this trivial schematic of a transistor buffer for driving motors - to see it click here.
