GSM Based Prepaid Electricity Energy Meter using Arduino

Overview

In this project, we will make a GSM Based Prepaid Electricity Energy Meter using Arduino. Prepaid Electricity Energy Meter is one of the best concepts for the current electricity payment system. In this system, you can recharge the device and update the balance as we do on our mobile phones.

By sending a simple SMS, you can recharge the electricity balance through this system. It can also disconnect the home power supply connection if there is a low or zero balance in the system. And this system will read the energy meter readings and automatically send some updates to the user’s mobile phone like low balance alert, cut off alert, resume alert and recharge alert. The Anti-Theft Alert can also be detected when someone tries stealing the meter by opening the lid. So, let us see how we can build this project.

There is an advance version of this project based on Internet of Thing, which you may look into:
1. IoT AC Energy Meter using Old Blynk
2. IoT AC Energy Meter using New Blynk
3. IoT DC Energy Meter

Bill of Materials

Following is the list of materials that you need to make an Arduino & GSM Based Prepaid Energy Meter. You can purchase all the components from the following link.

Hardware Setup & Circuit Diagram

The circuit diagram for GSM Based Prepaid Energy Meter is very simple. The Analog Electricity Energy Meter input terminal connects to 220V AC Power Supply. Its output terminal connects to the output of the single-channel Relay Module. All the loads for electricity also connect to the Relay as shown in the circuit.

The 16×2 I2C LCD Display connects to the I2C Pins of the Arduino UNO Board. We have used SIM800 GSM Module for GMS SMS functions which is the most important part of this project. The GSM has UART Pin as Tx & Rx which connects via Software Serial to digital pins 11 and 12 of Arduino. The GSM Module requires 9V Power Supply. So an external 9V DC power supply like DC Power Adapter can be used. Hence the GSM and Arduino both are powered via 9V DC Adapter.

The Relay, Buzzer, and Limit Switch are connected to D8, D7 & A0 of Arduino. Remember to take precautions as this circuit is dangerous due to AC Mains.

As shown here, you can assemble the circuit in a combined board. The top of the board has only the analog meter and LCD Display. Inside the box, the Arduino Board, GSM Module, Relay, and 4N35 Optocoupler IC are placed together. The Limit switch is placed at the opening of the meter door. It is used to check whether the box is opened or not and can prevent theft.

In this project, you can connect anything to the load such as Fan, Bulb, Heater, and everything that you use at home. To test this system you can connect the whole device directly to the 220V AC power supply.

How to Connect the Analog Meter to Arduino

The most important thing is how do you connect the meter to the Arduino. For this open the meter first. At the back of the meter, there is a Pulse LED or Cal LED terminals which are basically cathode and Anode.

You need to solder two wires to these terminals. After these, connect the anode & cathode terminal of the LED at pin number 1 and pin number 2 of the optocoupler. Now, this optocoupler is connected to digital pin D2 of Arduino.

Project PCB Gerber File & PCB Ordering Online

If you don’t want to assemble the circuit on a breadboard and you want PCB for the project, then here is the PCB for you. I used EasyEDA to design the PCB & Schematic. The Schematic & PCB Board for Prepaid Energy Meter looks something like the below.

The Gerber File for the PCB is given below. You can simply download the Gerber File and order the PCB from ALLPCB at 1$ only.

You can use this Gerber file to order high quality PCB for this project. To do that visit the ALLPCB official website by clicking here: https://www.allpcb.com/.

You can now upload the Gerber File by choosing the Quote Now option. From these options, you can choose the Material Type, Dimensions, Quantity, Thickness, Solder Mask Color and other required parameters.

After filling all details, select your country and shipping method. Finally you can place the order.

You can assemble the components on the PCB Board.

Source Code/program: Arduino GSM Prepaid Energy Meter

The complete program for GSM Based Prepaid Energy Meter using Arduino is given below. The code is mostly formatted for GSM AT Commands to recharge and test the system along with output feedback messages.

You need to make changes to the above lines in this code. Replace the mobile number in the following lines of the code with the number you want the SMS to send.

You can copy the code and upload it to the Arduino Board.

Project Working & Demonstration

When you power on the device, the LCD will display the unit, pulse, and price as zero.

Now we need to send an SMS to operate this device. Before that, we need to recharge this meter as there is no money to operate this device. You can recharge 100, 200, 300 & 400 at a single time. With the recharged money the electricity load will always be active as long as the amount doesn’t reach to zero.

To recharge with 100 balance, type ATrech1 & send. Here 1 means 100. If you want to recharge it with 200 simply replace 1 with 2. You will get a feedback message as an SMS that says “recharge is done”. The LCD will also display the same. Immediately the load will turn on.

As long as the pulse LED blinks, the counting goes on and the pulse count is displayed on LCD Screen. Also, there is a deduction in the recharged amount. We also set the limit to 60. As the amount goes to 60, the GSM will send an SMS saying the balance is low and you need to recharge it again. So basically, it’s an indication as well as a warning.

When the power consumption increases and the price goes further down till the amount reaches zero. In this instance, the load will turn off and there is an electricity cut-off. You will receive an SMS saying the balance is finished and you need to recharge it again.

So you can recharge again. A similar process continues again and again.

This process continues even after there is a power cut. This is because the last pulse count and price value are stored in the EEPROM of the microcontroller.

Video Tutorial & Guide