In recent days the usage of technology is inevitably seen in all forms of application. The emergence of new techniques in vlsi and corresponding improvement in embedded systems has opened the fled gates of electronics. The growth of embedded system in india has increased exponentially since last two years, the field has greater potential in the forthcoming years. Having this on mind we have taken our project on preliminary stage of circuit implementation using embedded system.

The project focuses on suppling power of 230V ac for the predetermined time which can be very well used for the domestic application like battery charging, mobile phone charging, and utilization of electronic gadgets. This setup can be made handy and kept on the streets for the usage like the coin phones.

The circuit operates with the power supply of 5V DC. The circuit consists of a simple and powerful IR transmitter and the IR receiver. When the coin is applied to the circuit which is designed in such a way to cut the transmitter, the triggering is applied to the interrupt pin of microcontroller. Here we use external interrupt 1.

The microprocessor computes the triggering signal and depending upon the programming of the controller it generates the time delay which is here 120 seconds. This is the time duration of the availability of power to the load circuit. During these 120 seconds the relay coil gets the supply voltage of 12V to its coil, there by latching the output circuit. After 120 seconds the circuit automatically turns off.

An LCD display is interfaced with the microcontroller to show the coin count and the remaining time from the dropping of the coin. The circuit also has an additional feature that is on incrementing the coin the time delay generated is proportionately increased.