The proposed system uses 89c2051 as smart card and 8051 as main micro controller. In smart card, we programmed maximum units to be used. This data is transferred to 8051. A digital energy meter is connected to 8051. 8051 is programmed to decrease the maximum units as a response to the information from digital energy meter. This system has a buzzer and it is used to alert the user. When maximum use is made relay will get cut off. Later by using push on switches, we can reset both micro controllers.  A scheme of Electricity billing system called “PREPAID ENERGY METER WITH TARIFF INDICATOR” can provide an improved cash flow management in the energy utilities. This system minimizes the usage of manpower for taking the meter readings and it also reduces the problems associated with billing consumer living in the isolated area.

A consumer can buy a memory card (i.e. EEPROM IC). By using a MC program, we stored a password inside that memory card. In this project, we defined the memory card as smart card. The memory card is available to the customer at various ranges (i.e. Rs. 50, Rs. 100, Rs. 200 etc).

The consumer inserts his smart card into the card reader which is connected to the kit. Later, the card reader reads the stored information in EEPROM IC (smart card) and by using the MC program, it deletes the information in smart card. So that, other users cannot use that smart card for another time. A consumer buys a smart card for Rs.50. Then he can insert this amount to the energy meter through the card reader. In this way, prepaid energy meter with tariff indicator kit will be activated. Based on the power consumption, the amount will be deducted. When the amount is over, the relay will shutdown the whole system automatically. In this system, the alarm will alert the consumer before the whole amount is reduced. So that, he can buy a smart card and activate the prepaid energy meter with tariff indicator kit.