Uses an 8051 and 89c2051.8051 as main microcontroller.89c2051 as smartcard and in it maximum units to be used is programmed.This data is given to 8051.8051 is connected to a digital energy meter.8051 is programmed to decrement the maximum units as a response to the information from digital energy meter.
There is a buzzer to warn the user.When maximum use is made relay is cut off.
Then we have to reset both microcontollers using push on switches. A scheme of Electricity billing system called "PREPAID ENERGY METER WITH TARIFF INDICATOR" can facilitate in improved cash flow management in energy utilities and can reduces problem associated with billing consumer living in isolated area and reduces deployment of manpower for taking meter readings.
Every consumer can buy a memory card (is nothing but an EEPROM IC) with a password stored inside it using a MC program. The memory card is available at various ranges (ie. Rs 50, Rs 100, Rs 200 etc).In our project we have given the name for memory card as smart card.
When the consumer insert a smart card into the card reader which is connected kit.Then the card reader will read the stored information and delete the information from the EEPROM IC(smart card) using the MC program.
So that the smart card cannot be reused by others. Suppose if a consumer buy a card for Rs.50/- he / she can insert this amount through the card reader so that prepaid energy meter with tariff indicator kit will be activated.
According to the power consumption the amount will be reduced. When the amount is over, the relay will automatically shutdown the whole system. In our project we also have a provision to give an alarm sound to consumer before the whole amount is reduced.