:: spoke n' light :: |
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overview | sketches | prototype-I | prototype-II | prototype-III | ||
![]() Rotating LED DisplayThe idea is to create a "screen" made of just one line of LEDs rotating at a high speed. The complete circuit (LEDs, microprocessor, power supply etc.) will be placed on a rotating wheel (bicycle, car, fan). A magnetic switch will "tick" the microprocessor every time the wheel has completed a circle, so that the rotation speed (and "zero" location) can be determined.A few interesting issues rise when analyzing the way a grid (Cartesian) image can be transformed into a "polar" image which can be displayed on this screen. A small MatLab function I wrote takes a grayscale image and transforms it to a set of vectors representing the intensity of each LED along the circle. The intensity of each LED is the average grayscale value of the original image at the LED's position. ![]() LED Super-resolution. By using two sets of LEDs shifted by 1/2 the diameter of a LED, the dark areas between two adjacent LEDs can be filled. ![]() Simulation. The original grid grayscale image (left), and its simulated polar representation (right) are shown below. The latter was generated using a couple of MatLab functions I wrote: grid2polar.m takes a regular grayscale image and generates its polar representation; simulate.m takes the polar vectors and simulates the result of sending those vectors to the rotating LED display. ![]() ![]() |