Check out the Einstein head which [Sebastian Müller] etched on the cover of his calculator using a laser engraver he made from scratch. We think he did a great job with the build, but we’re even more impressed with the work he put into sharing the techniques he used to salvage and repurpose all the components. It’s a perfect resource that should be pretty easy to adapt to different model/manufacturer source hardware.
He used an old scanner and an old printer for the bulk of the parts. These both originally included stepper-motor actuated gantries, which pull together to form the x and y axes in his Frankenstein Laser Engraver. As the parts came together he started in on the control electronics which include a couple of EasyDriver stepper motor boards and an Arduino.
At this point he took the machine for a test-run, attaching a marker to the carriage to use it as a pen plotter. After putting in a solid performance at this [Sebastian] moved on to adding in the laser diode. He covers how to drive the diode, as well as focal point alignment in great detail. It seems like his webpage post has the same content as the Instructable linked above but we wanted to leave the link just in case.