Introduction

1.1 Aim:

The primary goal of this project is to make use of an AT Mega16 microprocessor and C programming language, to build an electronic device that is able to detect the basic colours of an object, in our case, blue and read, and the result will be displayed on a LCD display.

1.2 Electronic components:

The electronic components involved in this device are:

• AT mega 16 microprocessor
• Sharp dot matrix LCD display
• Common anode LED light
• BYP62 bi-polar junction transistor
• Resistors

1.3 Background theories:

The primary idea of the device is to make use of reflection of light. When a colour light is projected on the object, if the object is of the same colour as the projection light, the reflection will be very strong; on the other hand, if the colour of the object is different from the projection light, there will be very weak reflection. In this device, a common anode LED, which produces red, blue and green(not used in this project) colour is used to emit the light to be object, the reflection light is caught by the base of the photo transistor. Black colour cardboards are placed around the LED and the phototransistor to prevent the light from emitting directly to the transistor, and also to reduce the disturb from the natural light. The reflection light creates a potential difference between the collector and the emitter, which is read in by the microprocessor, and the final result is displayed on the LCD screen.