A Low Cost Laser Graphics Projector.

I have developed a number of prototypes for this device.  By simulating the position of the moving ferrous mass on a high speed microcontroller in realtime, and then applying PID inputs to the physical magnetic coils as well as the simulated ones to optimally drive the mirror towards a desired scan position, a control system accurate enough for the projection of simple vector graphics is maintained for a period of time without the need for closed loop feedback.

The above prototype uses a ring of latex rubber - originally in liquid form as used for mold making - which connects the outside edge of the mirror (seen in the top center of the image) to the assembly chasis.  After experimenting with many different materials this offers a good compromise of quickly pulling the mass back to a rest position with minimal oscillation when the current to the magnetic coils is removed, and allowing the mass to be moved far enough that the reflected vector images can be resolved without the scanner unit having to be moved a great distance from the projection screen.