Project Hub /IoT & Connected Devices/Smart Home & Building Automation/ESP32 Bluetooth Low Energy (BLE) – Connecting to Fitness Band to Trigger a Bulb

Intermediate

ESP32

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

ESP32 Bluetooth Low Energy (BLE) – Connecting to Fitness Band to Trigger a Bulb

Learn how to configure an ESP32 as a Bluetooth Low Energy (BLE) client to detect a nearby fitness band by its unique MAC address and automatically trigger a connected lamp via a relay module.

Originally published on CircuitDigest

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. 858.00
5V 1 Channel Relay Module Rs. 87.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
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 Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: LED Bulb / Lamp / AC Load

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How It Works

This project establishes an automated control system using an ESP32 microcontroller acting as a Bluetooth Low Energy (BLE) client. Programmed via the Arduino IDE, the ESP32 periodically scans its surroundings for specific BLE broadcast signals, looking for the unique MAC address of a target fitness band. When the fitness band comes within range, the ESP32 recognizes the designated hardware identifier and changes the state of one of its digital output pins. Because the ESP32 operates at 3.3V logic and cannot directly drive high-voltage alternating current appliances, this control signal is routed to a relay module. The relay uses an electromagnetic coil—potentially isolated or driven via a transistor circuit like a BC548 if needed—to physically actuate a heavy-duty switch. This mechanical switching action safely bridges or breaks the connection to the AC load, such as a lamp plugged into mains power, causing the light to turn on or off based on the proximity of your wearable device.

Why Build This

Design and implement a practical IoT context-aware home automation prototype using wireless proximity detection.

Gain hands-on experience bridging low-voltage microcontroller logic with high-voltage AC electrical loads safely.

Explore advanced microcontroller communication protocols by configuring the ESP32 as an active BLE client.

Real-World Application

Automated home lighting that turns on when you enter a room wearing a wearable device like a fitness band or smartwatch, and turns off when you leave.

Skills You'll Learn

BLE client scanning

MAC address filtering

GPIO digital output control

relay module interfacing

AC load switching

microcontroller firmware development

Safety Precautions

Warning: The circuit deals with direct 220V AC mains voltage. Exercise extreme caution with live wires and ensure no short circuits occur.

Technology Tags

ESP32

BLUETOOTH LOW ENERGY

BLE CLIENT

RELAY MODULE

SMART HOME AUTOMATION

ARDUINO IDE

C++

WIRELESS PROXIMITY

Frequently Asked Questions

How do I find the unique MAC address of my fitness band?

You can use the nRF Connect mobile application on your smartphone to scan for nearby Bluetooth Low Energy devices and read their hardware MAC addresses.

Can I connect the AC lamp directly to the ESP32 output pin?

No, absolutely not. The ESP32 outputs 3.3V DC signals which cannot handle AC mains voltage, and direct connection will destroy the board and pose a severe shock hazard. You must use a properly rated relay module to isolate the low-voltage control circuit from the high-voltage load.

Does this project require an active internet connection or router?

No, this system relies entirely on local Bluetooth Low Energy (BLE) communication between your fitness band and the ESP32, so an external Wi-Fi network or internet connection is not necessary.

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-00060