Making a DIY text laser projector

Even though the resulting projector is quite simple in essence (you only need a laser, a mirror with a motor and a synchronization sensor), this method has a big downside — it’s very difficult to build a multi-faceted mirror at home. Laser printers use a polygonal mirror, set on top of a brushless motor to scan the laser beam along the paper. After supplying the clocking signal to the motor and power to the laser, you should point the laser in such a way that the beam hits the edges of the mirror.

Source: habr.com