Why This Project Matters

Most people only see their electricity consumption as a single number on a monthly bill. That makes it difficult to understand:

By collecting and visualising real-time measurements, this project makes electrical systems easier to understand and troubleshoot.

Potential applications include:

Hardware Requirements

ComponentsPurpose
Arduino UNO R4 WiFiMain controller with built-in Wi-Fi
PZEM-004T v3.0AC energy meter with Modbus interface
Current Transformer (CT)Non-invasive current measurement
SSD1306 OLED DisplayLocal readout
Push ButtonDisplay mode selection
ThingSpeakCloud dashboard
3D Printed EnclosureSafe and clean packaging
How It Works

The project follows a simple edge-to-cloud architecture.

  1. The PZEM-004T measures electrical parameters directly from the mains.
  2. The Arduino UNO R4 WiFi reads those values over Modbus RTU.
  3. Data is displayed on the OLED.
  4. The same values are uploaded to ThingSpeak using Wi-Fi.
  5. Historical graphs are generated automatically.

This provides both instant local feedback and long-term cloud logging.

System Architecture

AC Mains
   │
   ▼
PZEM-004T + CT Clamp
   │  (Modbus UART)
   ▼
Arduino UNO R4 WiFi
   ├── OLED Display
   └── ThingSpeak Cloud

Key Features

Measured Parameters

ParameterDescription
VoltageSupply health and stability
CurrentInstantaneous load demand
PowerReal power consumed
EnergyAccumulated usage over time
FrequencyGrid frequency
Power FactorElectrical efficiency

Why Arduino UNO R4 WiFi?

The UNO R4 WiFi is ideal for this project because it combines:

That means the firmware can read the meter, refresh the display, and upload to the cloud simultaneously without timing issues.

Firmware Design

The code uses a non-blocking timing structure based on millis().

Independent tasks run at different intervals:

This approach keeps the system responsive and easy to extend.

Local OLED Display

The OLED provides immediate access to the latest readings.

The push button cycles through:

This makes the monitor useful even without an internet connection.

Cloud Dashboard

ThingSpeak stores the uploaded data and plots it automatically.

This enables:

Viewing the graphs over time reveals patterns that are impossible to spot from a single utility bill.

Real-World Observations

Testing the project on household loads produced some interesting results:

These observations make the project both educational and practical.

Safety Notes

This project interfaces with mains voltage.

Important precautions:

If you are not experienced with AC systems, seek assistance from someone qualified.

Enclosure Design

To make the project deployment-ready, all electronics were installed inside a custom 3D printed enclosure with cutouts for:

The enclosure improves safety and gives the build a polished appearance.

Possible Upgrades

This platform can be expanded in several directions:

Build Challenges

A few practical issues surfaced during development:

Solving these challenges resulted in a reliable and responsive system.

What I Learned

This project provided hands-on experience with:

It sits in a sweet spot between beginner and intermediate embedded projects.

Performance Summary

The completed system successfully:

The result is a compact and practical smart-grid monitoring node.

Project Logs to Include on Hackaday.io

To maximize visibility and engagement, consider creating project logs for:

  1. Hardware assembly
  2. Wiring and safety tips
  3. Modbus communication setup
  4. OLED interface design
  5. ThingSpeak integration
  6. 3D printed enclosure
  7. Testing with real appliances
  8. Future improvements

Regular logs help attract followers and keep the project active in the Hackaday community.

Files to Share

Upload these assets to your Hackaday.io project page:

Conclusion

WattWise transforms a standard Arduino and energy meter into a powerful IoT instrument.

By combining real-time sensing, local visualization, and cloud analytics, the project provides meaningful insight into how electricity is actually used.

It is useful as a learning platform, a practical monitoring tool, and a foundation for larger Smart Grid in IoT and home automation projects.

If you enjoy projects that connect embedded systems, electrical engineering, and data visualization, this one is worth building.

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