Introduction to IoT - Lecture 3

What is Raspberry Pi?

Raspberry Pi is a credit-card-sized computer that plugs into a TV and a keyboard, functioning almost like a full-fledged computer. It was developed in the United Kingdom by the Raspberry Pi Foundation to promote computer science education in schools.

Key Features:

• Fully featured microcomputer on a circuit board.
• Uses Raspberry Pi OS (Linux-based) as the recommended operating system.
• Small footprint ($9\times 6$ cm) and affordable (priced between $5–35).
• Can connect to a monitor, keyboard, and mouse.
• Includes GPIO (General Purpose Input/Output) pins for interfacing with sensors and actuators.
• Ideal for learning programming, IT, and technical skills.
• Uses a microSD card as its hard drive.

Raspberry Pi Models

Aspect/Model	Raspberry Pi 1 Model A	Raspberry Pi 1 Model A+	Raspberry Pi 1 Model B	Raspberry Pi 1 Model B+	Raspberry Pi 2 Model B	Raspberry Pi 3 Model B	Raspberry Pi Zero
Release Date	2013	2014	2012	2014	2015	2016	2015
SoC	Broadcom BCM2835	Broadcom BCM2835	Broadcom BCM2835	Broadcom BCM2835	Broadcom BCM2836	Broadcom BCM2837	Broadcom BCM2835
CPU Speed	700 MHz ARM-1176JZF-S	700 MHz ARM-1176JZF-S	700 MHz ARM-1176JZF-S	700 MHz ARM-1176JZF-S	900 MHz ARM-Cortex-A7	1.2 GHz ARM-Cortex-A53	1 GHz ARM1176JZF-S
Cores	1	1	1	1	4	4	1
SDRAM	256 MB	256 MB	512 MB	512 MB	1 GB	1 GB	512 MB

Raspberry Pi Features

• Uses a Broadcom SoC with an ARM CPU and VideoCore IV GPU.
• CPU speeds range from 700 MHz to 1.2 GHz, with 256 MB to 1 GB RAM.
• SD/MicroSD cards store the OS and programs.
• Includes 1 to 4 USB ports, HDMI, composite video output, and a 3.5mm audio jack.
• GPIO pins provide lower-level output for hardware interfacing.
• Networking:
  • B-models have Ethernet.
  • Pi 3 and Pi Zero include Wi-Fi (802.11n) and Bluetooth.

Raspberry Pi 3 Highlights

• 1.2GHz 64-bit quad-core ARMv8 CPU.
• Built-in 802.11n Wi-Fi and Bluetooth 4.1 (BLE).
• Ideal for IoT projects, with multiple sensor connectivity.
• Features a 40-pin GPIO connector for external sensors and hardware integration.

Raspberry Pi Zero

• Smallest Raspberry Pi model.
• Less powerful than the Pi 3 but ideal for embedded projects like wearables due to its compact size.

Raspberry Pi Hardware

Raspberry Pi vs. Arduino

Arduino	Raspberry Pi
Development circuit board	Single-board computer
Microcontroller-based	Microprocessor-based
No OS	Runs Raspberry Pi OS (Linux)
Executes simple tasks	Can multitask with a full OS
Uses Arduino Shields	Uses Raspberry Pi HATs (Hardware Attached on Top)
Programmed in C/C++	Supports Python, Scratch, Ruby, C, C++
Logic voltage: 5V	Logic voltage: 3.3V
Requires shields for internet connectivity	Built-in Wi-Fi and Ethernet
Open-source: Can be modified by the public	Closed-source: Cannot be altered by the public
Standard boards cost $16–$20	Standard boards cost ~$35

Strengths

Arduino:

• Analog input and PWM support
• Real-time control for motors and sensors

Raspberry Pi:

• Full Linux OS with multi-threading
• Supports multiple programming languages
• Ideal for IoT, AI, and web applications

Raspberry Pi or Arduino

• Arduino: Best for precise software timing and simple tasks.
• Raspberry Pi: Ideal for internet connectivity, video display, and camera use.
• Both: Can be used together via I2C or SPI for advanced projects.

Getting Started with Raspberry Pi

Hardware Requirements:

• Essential:
  • Raspberry Pi board
  • MicroSD card
  • USB keyboard
  • Display (HDMI, DVI, or Composite input)
  • Power supply
• Recommended extras:
  • USB mouse
  • Internet connection (LAN or Wi-Fi)
  • Heat sink for the processor
  • Protective case

Operating System (OS):

• The Raspberry Pi OS (formerly Raspbian) is recommended.
• Can also run Ubuntu MATE, Windows 10 IoT Core, and other third-party OS.
• Installed using the Raspberry Pi Imager tool.

Connecting to Wi-Fi

To connect your Raspberry Pi to Wi-Fi:

1. Insert the microSD card.
2. Connect a monitor, keyboard, and mouse.
3. Power on the device and follow on-screen instructions to set up Wi-Fi.

Using the Linux Terminal

Raspberry Pi OS (Linux based) comes with a GUI but relies heavily on terminal commands for system management.

Updating Raspberry Pi OS:

# Update package repositories
sudo apt update

# Upgrade all installed packages
sudo apt full-upgrade

Shutting Down Properly:

Unlike other devices, the Raspberry Pi has no off switch.

• Do not unplug it directly.
• Use the terminal to shut it down safely:

sudo shutdown # or sudo poweroff

This ensures a clean shutdown before unplugging the power source. To turn it back on, simply plug it in.

Remote Access

To remotely access your Raspberry Pi from a desktop computer, you can use:

• SSH – Command-line access
• Remote Desktop software, such as:
  • XRDP/RDC (not for root user)
  • TeamViewer
  • VNC

Python with Raspberry Pi

Python, an older language (1991) compared to C# (2000), Swift (2014), Java (1995), and PHP (1995), comes pre-installed on Raspberry Pi OS with the built-in Thonny editor for coding.

LED Blinking Example:

This simple script continuously blinks an LED connected to GPIO pin 16.

from gpiozero import LED  # Import LED control from gpiozero
from time import sleep    # Import sleep for delays

pin = 16          # Define the GPIO pin where the LED is connected
led = LED(pin)    # Create an LED object

while True:       # Infinite loop to blink the LED
  led.on()        # Turn the LED on
  sleep(1)        # Wait for 1 second
  led.off()       # Turn the LED off
  sleep(1)        # Wait for 1 second