|
This Project is help for Nursery School Children, It automatically changes Alphabets from A to Z with short delay in-between every two alphabets displaying on 5X7 (35 LED s) dot matrix display. This display can be made by arranging 35 common 5 mm LEDs in a matrix of 5X7, 5 columns and 7 rows. The heart of the circuit is AT89C2051 (20 Pins ATMEL Micro-controller) with its software program. 24 Nos. of Common NPN Transistors 2N2222 are used in the form of Darlington pairs.One Push button is placed to stop the auto change sequence of alphabets to stick at particular Alphabet.The another push will continue the change sequence of alphabets. 7 Rows Darlington pairs transistors (Feeding 7 Rows LEDs Anodes) are powered 6 Volts DC directly at their collectors to give more power for LEDs brightness |
|
