Thursday, January 14, 2010

POV based LED Display

POV-persistence of vision

 

ABOUT THE PROJECT

This is my 2 semester physics  project.I did it along with  3 of my  friends-Rejun , Rohit and Anenth . Most of us thought this project was way beyond our reach .Even our colleges thought this was too much for a bunch of first year computer nerds.

This is basically a column of 6-8 LED’s which are rotated at approximately 25 – 30 rps (2000 rpm) to produce an illusion of a full width screen. which is then used to display text or images.

 

HOW IS THIS POSSIBLE ?

As i said its persistence of vision.The eye basically cant process images that move faster than 18-24 rps , so the eyes treat them as a single image.This flaw of the eye is used to create the illusion of a full image, by controlling the rate and order at which all the LED’s blink and their respective delay.

HOW DO WE MAKE THE LED’s BLINK ? 

The correct order and the delay of the led is controlled by a ATMega8 processor .We then program it, with the correct order and the delay  each LED must undergo in C language and burn it to the EEPROM (ATMega8) using a AVR programmer, connected to the computer..

THE TOUGH PART

Programming the EEPROM to display text is the tough part….lots and lots of programming.Getting the right delay time is the toughest part , once solved , everything else turns out to be easy.