Project Hub /IoT & Connected Devices/Smart Home & Building Automation/Smart Plug with Android Interface

Intermediate

ANALOG / DISCRETE

Project Specific

3 – 6 Hours

Partial Kit

Smart Plug with Android Interface

A DIY smart plug project that measures voltage, current, power, and Watt-hours of a load and allows wireless control and monitoring via an Android smartphone.

Originally published on ElectronicsForU

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

ESP32 WiFi+Bluetooth CP2102 Development Board Rs. 520.00
5V 1 Channel Relay Module Rs. 45.00
10pcs 5mm RED Diffused Light Emitting Diodes - LEDs Set Rs. 39.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: Current Sensor ACS712
Transformer
Diodes (1N4007 / 1N4148 / Schottky / Zener)
Renesas GR Peach Controller
Voltage Divider Circuit

Browse all components

How It Works

The Smart Plug system integrates power management, sensing, and wireless communication around the Renesas GR Peach Controller. To monitor energy usage, the appliance connects through a 230V to 5V rectifier circuit that powers the low-voltage electronics while stepping down the high-voltage input for measurement. A voltage divider circuit scales the AC voltage down to a safe level readable by the controller. Simultaneously, the ACS712 current sensor measures the electrical current drawn by the load, providing an analog feedback signal proportional to the current. The Renesas GR Peach processes these voltage and current measurements to calculate real-time parameters such as power and cumulative Watt-hours. For system status, a supervisory LED provides visual feedback. User interaction and monitoring take place remotely via an Android smartphone developed using App Inventor. The smartphone communicates wirelessly with the system using an HC-06 Bluetooth module, transmitting commands to toggle a relay module that physically connects or disconnects the 230V AC mains power to the load, while simultaneously receiving calculated energy consumption metrics for display.

Why Build This

Design and implement a functional Internet of Things (IoT) home automation node that tracks real-time voltage, current, power, and cumulative Watt-hours.

Develop custom mobile applications using App Inventor to interface with embedded hardware over Bluetooth for remote appliance management.

Gain practical experience safely integrating high-voltage AC mains circuits with low-voltage microcontroller logic.

Real-World Application

Home automation, energy monitoring, and remote appliance management to track and optimize power consumption.

Skills You'll Learn

AC-DC power conversion

analog signal scaling with voltage dividers

current sensing with Hall-effect sensors

relay control of high-voltage loads

wireless serial communication via Bluetooth

graphical mobile app development

Safety Precautions

Exercise extreme caution when working with 230V AC mains electricity to avoid electric shock or short circuits.

Technology Tags

BLUETOOTH

ANDROID

APP INVENTOR

CURRENT SENSOR

RELAY

AC POWER MEASUREMENT

Frequently Asked Questions

Can I connect the Bluetooth module directly to the 230V mains?

No, the HC-06 Bluetooth module operates on low-voltage DC and must be isolated entirely from the high-voltage AC mains section, communicating only with the low-voltage microcontroller logic.

How does the Android phone communicate with the Renesas GR Peach?

The Android smartphone pairs and communicates wirelessly with the HC-06 Bluetooth module, which passes serial data back and forth with the Renesas GR Peach controller.

What is the purpose of the 230V to 5V rectifier circuit?

It steps down and rectifies the high-voltage AC mains supply to provide a stable low-voltage DC power source necessary for running the microcontroller, sensors, and logic circuitry.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

PRJ-00583