Esp32 Smart Plug Energy Monitor — this practical project guide shows you how to build a complete working system from scratch, with affordable components available in India.
Table of Contents
- Project Overview and Use Cases
- Components and Bill of Materials
- Circuit Diagram and Wiring
- Code Walkthrough
- Web Interface and Controls
- Testing and Calibration
- Enclosure and Deployment Tips
- Frequently Asked Questions
Project Overview and Use Cases
This project combines the power of ESP32, Smart Plug, Energy to create a practical, real-world solution that Indian makers and engineers can build at home. The total component cost stays under ₹1,500 for most configurations, making it accessible for students and hobbyists. Whether you are building this for a college project, a personal smart home, or a prototype for a startup idea, the architecture is designed to be reliable and extensible.
The ESP32 microcontroller handles all the processing, WiFi connectivity, and sensor interfacing in a single chip. No additional modules are needed for basic functionality — just power it up, flash the firmware, and connect to your WiFi network.
Components and Bill of Materials
Here is the complete bill of materials for this project:
- ESP32 Development Board — the main controller (₹400–₹600)
- Sensor/Module — specific to this project (₹150–₹400)
- Breadboard and Jumper Wires — for prototyping (₹100)
- USB Cable — for programming and power (₹50)
- 5V Power Supply — for standalone deployment (₹150)
Total estimated cost in India: ₹850–₹1,300. All components are readily available from Zbotic with fast shipping across India.
Circuit Diagram and Wiring
Connect the components following this wiring guide. The ESP32 uses 3.3V logic levels — do not connect 5V signals directly to GPIO pins without a level shifter. Use short jumper wires to minimise noise, especially for analog sensors and communication buses.
For permanent installations, solder the connections on a perf board or custom PCB. Indian PCB fabricators like PCBPower offer 10 boards for ₹200–₹500 with 2-3 day delivery. Use JST connectors for modules you might want to replace later.
Code Walkthrough
The firmware is written in Arduino C++ and uses the following key libraries. Install them via Arduino IDE Library Manager before compiling.
#include <WiFi.h>
const char* ssid = "Your_WiFi";
const char* password = "Your_Password";
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("nConnected: " + WiFi.localIP().toString());
// Initialise sensors and peripherals
initHardware();
}
void loop() {
// Read sensors
float reading = readSensor();
// Process and transmit
if (millis() - lastSend > interval) {
sendData(reading);
lastSend = millis();
}
}Adjust the sensor reading interval based on your application. For temperature monitoring, every 30 seconds is sufficient. For motion detection, read as fast as possible (10ms intervals).
Web Interface and Controls
The built-in web interface provides a responsive dashboard accessible from any device on your WiFi network. Open a browser and navigate to the ESP32’s IP address to see real-time data, control outputs, and configure settings.
The HTML interface uses modern CSS Grid layout with touch-friendly buttons sized at 48px minimum for comfortable mobile use. Data updates automatically via JavaScript fetch() calls every 2 seconds, giving a smooth, app-like experience without page reloads.
Testing and Calibration
After assembling the hardware and uploading the firmware, follow these testing steps:
- Open Serial Monitor at 115200 baud and verify WiFi connection
- Check the IP address and open it in a browser
- Test each sensor reading against a known reference
- Verify all control outputs respond correctly
- Run the system for 24 hours and check for memory leaks or disconnections
For sensor calibration, take multiple readings at known reference points and apply a linear correction factor in code. Document your calibration values for reproducibility.
Enclosure and Deployment Tips
For permanent deployment, house the electronics in a suitable enclosure. IP65-rated junction boxes from local electrical shops cost ₹50–₹150 and protect against dust and water splashes. Use cable glands for wire entry points. Add ventilation holes (covered with mesh) if the enclosure contains heat-generating components like relays.
Mount the ESP32 on standoffs inside the enclosure. Use hot glue to secure loose wires and prevent vibration-related disconnections. Label all connections for future maintenance.
Frequently Asked Questions
How much does an ESP32 board cost in India?
ESP32 development boards are available in India from ₹400 to ₹800 depending on the variant and features. Basic ESP32-WROOM-32 boards start at ₹400 while ESP32-S3 with display can cost up to ₹2,500. Zbotic offers competitive prices with fast domestic shipping.
How accurate are the sensor readings?
Accuracy depends on the specific sensor module and calibration. Most hobby-grade sensors achieve ±2-5% accuracy, which is sufficient for monitoring applications. For precision measurement, invest in calibrated industrial sensors and apply correction factors in code.
How long will the battery last?
Battery life depends on sleep mode configuration and transmission frequency. With deep sleep (10 µA) waking every 15 minutes to send data, a 2000 mAh LiPo battery can last 6-12 months. Active WiFi mode draws 80-240 mA.
Where can I buy ESP32 boards in India?
Zbotic.in offers a wide range of ESP32 boards and accessories with competitive prices and fast shipping across India. We stock genuine and high-quality components suitable for both prototyping and production use.
Can I use this project for my college engineering project?
Absolutely! This project covers concepts from embedded systems, IoT, and wireless communication — all relevant to B.Tech and M.Tech curricula. Add proper documentation, a literature survey, and performance metrics to make it submission-ready.
Conclusion
The ESP32 platform continues to impress with its versatility and value for money. This project demonstrates just one of hundreds of applications possible with affordable microcontrollers. Indian makers have a unique advantage — access to affordable components, a growing community, and endless real-world problems to solve with technology. Whether you are building this for learning, a college project, or a commercial product prototype, the fundamentals covered here will serve you well.
Ready to start building? Browse our complete range of ESP32 development boards and modules at Zbotic for the best prices in India with fast shipping!
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