Testing the display. The 10-sided polygonal mirror was powered by a dremel tool.
I built this display as part of a project for my "Digital Systems Laboratory" (6.111) class. Basically I projected a 532nm laser beam onto a spinning polygonal mirror, which deflected the light at different angles to allow simple images to be displayed. Infrared break-beam sensors on the spinning head allowed for crude positioning and control over the beam. An FPGA modulated the light shining out of the laser in order to display specific patterns or images.
Here is an early test of the system, in which I was aligning the mirrors.
Here the mirror assembly is stationary, so you can see the concentrated beam in this time-exposure photograph.
This images was from an early test on a weaker red laser module. Unfortunately it could not be switched fast enough so I had to find a fancier laser module (the green laser shown above).
The duty cycle of the pulse train emitted by the laser should be 50%, but in reality it is somewhat less since the laser could not switch quite fast enough. The effect was much more pronounced at higher frequencies (not shown here) which I planned to operate at.
More info coming...
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