Miguel turned a broken EPSON printer in to a LASER CUTTER using an ADAFRUIT motorshield for ARDUINO! He writes -

When my EPSON 830U decided not to work for me anymore (printing heads clogged) I thought I could make some use of the still working mechanics of the printer. It’s based on a couple of stepper motors for both axis of motion (print head and paper feed).

So I replaced the original power supply and drive electronics for an arduino board and an stepper motor driver from Adafruit industries. Now I could move the printhead
anywhere on a page. Next step was to add a laser on the printhead and to control it using a PWM output from arduino (so laser power could be modulated from the computer).

Though it only cut thin back color cardboard, it has may uses. I wrote a C program for arduino to control the stepper motors and laser. It receives data from the computer and
interfaces with the old printer guts.

Data format is very simple: each line contains a sequence of integer numbers separated by blank space. Each pair of numbers represents one XY coordinate. Line ends with a CR (0x0d) character (that also shuts down the laser to stop cutting). First coordinate of a line sets the starting point (before reaching that location the laser is off).

I wrote some software running on my iMac that reads a Inkscape SVG file (only straight lines are supported though, use Flatten Bezier on curves to get a sequence of straight line segments) and translates it to the desired data format for arduino and it shows a preview on the screen. Data is sent through a USB port to the arduino. iMac code was written using Processing language (Java-based) so it can run on Windows or Linux too.

If you have an old EPSON printer, you may want to give it a second thought before putting it to the trash.