Smart RGB LED Lamp — BLE Controlled (ESP32)

A Bluetooth Low Energy (BLE) controlled RGB LED lamp built on the ESP32 microcontroller. The lamp supports multiple lighting modes, real-time color and brightness control, and temperature monitoring — all controllable wirelessly via nRF Connect app. A dedicated mobile application is currently under development.

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PCB Design (Eagle)

Schematic and board layout designed in Eagle CAD.

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Printed & Assembled PCB

Physical PCB after printing and soldering.

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Control via nRF Connect

The lamp is currently controlled using the nRF Connect mobile app. Temperature readings are exposed as a BLE characteristic and visible directly in the app.

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Lighting Modes

Random Color — Physical Button

Press the physical button to apply a random color using ESP32's hardware RNG.

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Candle Mode

Simulates a realistic flickering candle effect.

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Pulse Mode

Smooth brightness breathing effect.

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Wave Mode

Seamless smooth transitions across the full RGB spectrum.

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Features

• Full RGB color control — set any color via BLE (values 0–255 per channel)
• Brightness control via MOSFET PWM (low-side configuration)
• Temperature monitoring — DS18B20 sensor exposed as a BLE characteristic
• Random color button — applies a random color using ESP32's hardware RNG
• Lighting modes:
• Candle (flicker simulation)
• Pulse (breathing effect)
• Wave (smooth RGB transitions)
• BLE communication — controlled via nRF Connect (dedicated app in development)

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Pin Configuration (ESP32 DevKit)

Pin	Function	Component
23	Red channel (PWM)	RGB LED — Red
24	Green channel (PWM)	RGB LED — Green
25	Blue channel (PWM)	RGB LED — Blue
9	1-Wire data	DS18B20 Temperature Sensor
11	Button input	Random color trigger

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Hardware Components

Component	Description
ESP32 DevKit	Main microcontroller with built-in BLE
RGB LED 3W (Star)	High-brightness point light source
MOSFET (×3)	Low-side PWM drivers for each RGB channel
LM2596 Buck Converter Module	Steps down 12V supply to 3.3V for ESP32
DS18B20	Digital 1-Wire temperature sensor
Resistor 33Ω 5W	Custom current-limiting resistor
Push Button	Physical control for random color

The repository includes pre-built external libraries for ESP32 DevKit, DS18B20, and the custom 33Ω 5W resistor component (Eagle library).

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Libraries

The project uses the following external libraries bundled in the repository:

• ESP32 BLE Arduino — BLE GATT server implementation
• DallasTemperature + OneWire — DS18B20 sensor support
• Custom Eagle component library — 33Ω 5W resistor footprint

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Setup

1. Open the project in Arduino IDE or PlatformIO
2. Select board: ESP32 Dev Module
3. Install libraries from the /libraries folder (or use the bundled ones)
4. Flash the firmware to your ESP32
5. Open nRF Connect on your mobile device
6. Scan for the device and connect
7. Use GATT characteristics to:
   • Write RGB values (3 bytes: R, G, B)
   • Write lighting mode
   • Read temperature

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BLE Control (nRF Connect)

Until the dedicated app is released, the lamp can be fully controlled via nRF Connect:

• Write [R, G, B] bytes to the color characteristic to set color
• Write a mode byte to switch lighting modes:
  • Candle — Candle
  • Pulse — Pulse
  • Wave — Wave
• Read the temperature characteristic to monitor the LED temperature

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Project Info

• University: Silesian University of Technology
• Faculty: Faculty of Automatic Control, Electronics and Computer Science
• Subject: Microprocessor and embedded systems
• Author: Maciej Porębski