Smart Energy Meter: Real-Time Power Monitoring with ESP32 and PZEM-004T

Why a Smart Energy Meter Is a Strong FYP Choice

Electricity monitoring projects have a rare advantage: the problem statement writes itself. Rising TNB tariffs, household energy waste, and sustainability targets are all things a panel immediately understands without you having to justify the topic for five minutes.

It's also a project with real depth — you're working with actual AC power measurement (not just a simulated sensor), pushing live data to a dashboard, and optionally adding cost calculation and appliance-level breakdown. That range of technical work is exactly what separates a pass from a distinction.

Hardware Components

Component	Purpose	Cost (RM)
ESP32 Development Board	Microcontroller + WiFi	RM 20–30
PZEM-004T v3	AC voltage/current/power sensor	RM 30–45
Current Transformer (CT) Clamp	Non-invasive current sensing	Included with PZEM
OLED Display 0.96"	Local readout	RM 10–15
Relay Module 5V	Remote appliance cut-off (optional)	RM 5–8
Enclosure	Safety housing for AC wiring	RM 15–25

Total hardware cost: RM 80–125

Safety note: this project involves live AC mains wiring. The PZEM-004T is designed to be safe when installed correctly, but supervise any mains-side wiring with your supervisor or an experienced technician before your first test.

How It Works

1. The PZEM-004T sensor clamps around the live wire (non-invasive, no need to cut the wire) and measures voltage, current, active power, and energy consumed over time
2. The ESP32 reads this data from the PZEM module over UART (Modbus protocol)
3. Readings are displayed locally on the OLED and pushed to a cloud dashboard (Blynk, Firebase, or a custom web app) every few seconds
4. The system calculates estimated cost using Malaysia's TNB tariff structure
5. Optionally, if power draw exceeds a threshold you set, the relay can automatically cut power to a connected appliance

Wiring Overview

PZEM-004T to ESP32 (UART):

• PZEM TX → ESP32 RX2 (GPIO 16)
• PZEM RX → ESP32 TX2 (GPIO 17)
• PZEM GND → ESP32 GND

PZEM AC side: live and neutral wires pass through the module per the manufacturer's diagram, with the CT clamp around the live wire only.

OLED (I2C):

• SDA → GPIO 21
• SCL → GPIO 22

Core Logic (Pseudocode)

void loop() {
  float voltage = pzem.voltage();
  float current = pzem.current();
  float power = pzem.power();
  float energy = pzem.energy();

  float estimatedCost = calculateTNBCost(energy);

  displayOnOLED(voltage, current, power, estimatedCost);
  pushToDashboard(voltage, current, power, energy, estimatedCost);

  if (power > THRESHOLD_WATTS) {
    triggerRelayOff();
    sendAlert("High power draw detected");
  }

  delay(2000);
}

For the TNB cost calculation, Malaysia uses a tiered tariff (higher rate per kWh above certain thresholds) — implementing this tiered logic instead of a flat rate is a nice technical detail that examiners notice.

Dashboard Options

• Blynk — fastest to set up, good for a simple gauge + graph demo
• Firebase + custom web app — more work, but lets you show historical trends and per-day/per-month breakdowns, which scores well for "software depth"
• ThingSpeak — free, simple, good for showing data logging over weeks

Presentation Tips

• Show live readings while plugging in and unplugging an appliance — the number changing in real time is the strongest part of the demo
• Have a week or two of logged data ready before your viva; a live demo with only 10 minutes of history looks thin
• Be ready to explain how the CT clamp measures current without direct electrical contact — it's a common examiner question

Scope Recommendations

For a Diploma FYP: Live readings on OLED + basic dashboard For a Degree FYP: Add TNB tariff cost calculation + historical logging For Merit/Distinction: Add automatic relay cut-off, mobile app, and per-appliance monitoring with multiple PZEM units

Need This Project Done?

Rectronx Circuits builds complete smart energy monitoring systems — safe AC wiring, dashboard setup, and full FYP documentation included. WhatsApp us for a free quote within 2 hours.

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