DESIGN AND CONSTRUCTION OF 8-WAY TRAFFIC LIGHT CONTROLLER.

Abstract

The project is a model of 8-way cross junction traffic control system which is built around the TTL (transistor transistor logic), for broad roads used in highly populated areas to control traffic. The circuit is adopted from a 20 output sequencing circuit. It has an oscillator (555 timer), a 4 bit decade counter, a logic control unit and output indicator. The oscillator deals with the circuit's timing operation. The 4 bit decade counter generates 10 logic states which is expanded to 20 active low outputs by the logic control unit. The latter unit holds a logically configured network of PN diodes for realizing a particular output lighting sequence. The output involves a set of switching circuit for isolated relatively high current to switch on the output light emitting diodes (LEDs). The involved lighting are light emitting diodes, an improvement of the usual high power consumption and relatively short life halogen lamps. v