The Prepaid Energy (kWh) Meter using RFID Technology is an intelligent energy management system designed to monitor electricity consumption based on prepaid credit. The system uses an RFID reader and RFID tags/cards for recharging the energy balance. Users can recharge the meter by scanning an RFID tag containing a predefined amount of credit. A keypad is provided to select different tariff rates such as ₹10, ₹20, and ₹30 per unit, allowing flexible billing according to user requirements. The PIC microcontroller continuously receives pulse signals from the energy meter through an optocoupler and calculates the consumed energy. The available balance and energy consumption details are displayed on an LCD screen. As electricity is consumed, the corresponding amount is deducted from the prepaid balance. When the balance reaches zero, the microcontroller automatically activates a relay to disconnect the power supply to the load, preventing further energy usage. A buzzer and LED indicators provide alerts for low balance and recharge status. This system helps consumers manage electricity usage efficiently, eliminates manual meter reading, and ensures transparent and controlled energy consumption.    

The main objectives of the project are:  

  To design and develop a prepaid energy meter for monitoring and controlling electricity consumption based on available credit.

  To implement RFID-based recharge functionality for quick, secure, and user-friendly balance updating.

  To provide tariff selection through a keypad, enabling users to choose different rates such as ₹10, ₹20, and ₹30 per unit.

  To display energy consumption and remaining balance in real time using an LCD display.

  To automatically disconnect the power supply using a relay when the prepaid balance is exhausted and restore supply after recharge.      

The major building blocks of this project are:

1. Regulated Power supply.
2. PIC Microcontroller.
3. RFID Reader.
4. RFID TAG.
5. Digital Energy Meter.
6. Optocoupler.
7. Keypad (Three Buttons).
8. Crystal oscillator.
9. Electromagnetic Relay with driver.
10. LCD Display with driver.
11. LED indicators.
12. Buzzer with driver.

      Software’s used:  

1. PIC-C compiler for Embedded C programming.
2. PIC kit 2 programmer for dumping code into Micro controller.
3. Express SCH for Circuit design.

      Regulated Power Supply:

         

Block Diagram:        

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