Abstract: In this paper, the idea of prepaid energy meter using an AT89S52 microcontroller and GSM module has been introduced. The aim of the project is to make a reliable and user friendly technology to purchase credit electricity in advance of power consumption. This provides a cost efficient manner of electricity billing. The present energy billing systems are discrete, time consuming, inaccurate, costly and slow. The major drawback of traditional billing system is power and energy theft. This drawbacks are reduced by the concept of credit power before consumption. The advent of microprocessor based devices and meters has greatly improved the ease of operation, making the system user friendly. The GSM technology is used so that the consumer would receive messages about the consumption of power and automatically alert the consumer to recharge when the recharge reaches minimum amount. The automated billing system will keep track of the real time consumption.

Keywords: Microcontroller, Energy meter, GSM module, Opto-coupler, Relay.