IEEE Maker Project

Attention Makers

CATEGORY: ROBOTICS

32

Color Detecting Auto Sorting Robot

MAKERS: Muhammad

The goal of this project was to construct and design a color detecting auto sorting robot. This robot detects the color of an object and automatically sorts the object according to its color. It uses RGB light and is able to detect 12 colors but it can be programmed/trained to detect and sort more colors. This project is made under 3500 pkr equivalent to 35USD$ all the work is done by three student team From University of Management and Technology. this was the prototype for our final year project. Since it was self financed we try to keep its cost as low as we can. all pcbs are self manufactured and self designed. A popular pic 16f877a is used. Pic basic language is used to made its firmware. For prototype we use wood and junk we had that time. We made temporary lab for this work. Remarkable thing is that it doesn't use camera or any imaging device to detect color and it is made without using any image processing stuff. Who can say a simple LDR, red, blue and green LEDs with a micro-controller are powerful enough to detect nearly 100 different colors? How it works principle behind this project is reflection of light. light(typically white light) is a collection of electromagnetic waves with different frequencies.when a certain wave with a certain frequency fall on our eye we see it as a color. our eye can see 2.3 million colors(basically a same type of wave with 2.3 million different frequencies). for simplicity lets say. black ball absorb all colored lights, green ball reflect only green light waves with 526~606 THz frequency and absorb all other colored lights. if we fall red green and blue primary color lights, one by one on any colored ball, we can observe three different reflecting light intensities.reflecting intensity of a red light is high from red object. blue object reflect blue light more. pink color is mixture of blue and red so pink object reflect blue and red lights more but green light will not reflect well from pink ball. each color ball will have three unique reflecting intensities. We made voltage divider with LDR and 10k resistence. and use pic micro-controller for A2D conversion that's how we where able to measure intensity of light reflecting back from ping pong balls. Then we fall red blue and green lights on the surface of ping pong ball and record three intensities reflecting from the surface of ball. simple algorithm (previousintensity + currentintensity)/2 use to train micro controller for same colored ball. 5 to 10 samples are taken for training of rgb intensities. noise is compensated by adding +-5% tolerance in intensity matching formula. external light act as noise. For sorting, two car power window motors are used. rotating motor have 12 sliding switches below each jar and a complex switching scheme use to stop motor. Made by: Muhammad Anas Javaid Jamal Anwar Muhammad Zubair Advised by Saleem Atta