Smart Node

This project uses a Raspberry Pi 5 to:

• Read sensor data from DHT11 (temperature & humidity) and BH1750 (light intensity).
• Display the sensor values on an ILI9341 LCD screen.
• Publish the sensor data to an MQTT server.
• Control an LED using PWM.

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Wiring Details

🔹 BH1750 Light Sensor

BH1750 Pin	Raspberry Pi 5 Pin
VCC	Pin 1 (3.3V)
SCL	Pin 5 (GPIO 3 / SCL1)
SDA	Pin 3 (GPIO 2 / SDA1)

🔹 DHT11 Temperature & Humidity Sensor

DHT11 Pin	Raspberry Pi 5 Pin
Data	Pin 7 (GPIO 4)

🔹 LED (PWM Controlled)

LED Pin	Raspberry Pi 5 Pin
Anode	Pin 32 (GPIO 12 / PWM0)

🔹 ILI9341 LCD (SPI Interface)

LCD Pin	Raspberry Pi 5 Pin
LED	3.3V
SCK	Pin 23 (GPIO 11)
SDI/MOSI	Pin 19 (GPIO 10)
D/C	Pin 12 (GPIO 18)
RESET	Pin 16 (GPIO 23)
CS	Pin 24 (GPIO 8 / SPI0_CE0)
GND	GND
VCC	5V

🔹 Paho MQTT

• sudo apt update
• sudo apt install git cmake build-essential libssl-dev

Paho MQTT C

Clone Paho MQTT C

• git clone https://github.com/eclipse/paho.mqtt.c.git
• cd paho.mqtt.c

Build

• cmake -Bbuild -H. -DPAHO_WITH_SSL=TRUE
• sudo cmake --build build/ --target install
• sudo ldconfig

Paho MQTT C++

Clone Paho MQTT C++

• cd ..
• git clone https://github.com/eclipse/paho.mqtt.cpp.git
• cd paho.mqtt.cpp

Build

• cmake -Bbuild -H. -DPAHO_WITH_SSL=TRUE -DPAHO_BUILD_STATIC=FALSE
• sudo cmake --build build/ --target install
• sudo ldconfig

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Features

• Real-time sensor readings displayed on LCD.
• MQTT communication for remote monitoring.
• PWM control for LED brightness based on ambient light.