What is embedded Linux?
Embedded Linux is an operating system based on Linux optimized for embedded devices. Unlike traditional distributions, it is designed to operate in resource-constrained environments and offer a high degree of customization.
- Embedded Linux: Ideal for systems with a graphical interface, advanced connectivity, and higher processing capacity.
- RTOS (such as FreeRTOS): More efficient in real-time critical systems, such as industrial controllers or medical systems.
Why use Raspberry Pi for embedded systems?
- Accessibility and low cost.
- Large community and documentation.
- Compatible with various embedded Linux distributions.
- Adequate processing capacity for IoT and automation.
Getting started
Hardware description
- Raspberry Pi Models: Raspberry Pi 4, 3B+, Zero W, among others.
- Compatible Peripherals: Camera modules, sensors, touch screens.
Required components
- SD Card (minimum 8GB, class 10 recommended).
- USB-C or micro-USB power supply depending on the model.
- HDMI cable (optional for configuration with a monitor).
- USB keyboard and mouse (optional).
Setting up
Downloading and installing the operating system
- Download Raspbian (Raspberry Pi OS) or Ubuntu Core from their official sites.
- Use other options such as:
- Yocto Project: To fully customize the operating system.
- Buildroot: Lightweight and optimized for embedded systems.
- OpenWrt: Ideal for network systems.
- Use tools like Raspberry Pi Imager or balenaEtcher to write the image to the SD card.
- Insert the SD card into the Raspberry Pi and turn it on.
Initial setup
- Wi-Fi network connection using raspi-config.
- Enabling SSH for remote access.
- Configuration of time zone, keyboard, and language.
To configure Wi-Fi manually without GUI:
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
Add:
network={
ssid=”ReadWifi”
psk=”password”
}
Basic Linux commands
File system navigation
- ls, cd, pwd, cp, mv, rm.
Process and service management
- ps, top, kill, systemctl.
Software installation
- apt-get install package for software from the official repository.
- pip install package for Python packages.
Embedded development
Cross-Compilation setup
- Use of gcc and make in cross-development environments.
- Installation of appropriate toolchains for Raspberry Pi.
Writing and deploying applications
- Programs in C and Python for execution on the Raspberry Pi.
- Use of libraries such as RPi.GPIO and gpiozero for GPIO control.
Example of UART usage in Python:
import serial
ser = serial.Serial(‘/dev/serial0’, 115200) # UART on Raspberry Pi
ser.write(b’Hello Embedded Linux!’)
Example projects
- Remote monitoring system (sensors + web server).
- Headless operation (running without a monitor).
- Custom Linux image for embedded use.
- IoT Gateway with MQTT to connect sensors and devices.
- Automation with Node-RED or Python + Flask for an embedded web server.
Example of a Flask server on Raspberry Pi:
from flask import Flask
app = Flask(__name__)
@app.route(“/”)
def home():
return “¡Hi from Raspberry from Embedded linux!”
if __name__ == “__main__”:
app.run(host=”0.0.0.0″, port=5000)
Advanced topics
Kernel and device tree customization
- Compiling a custom kernel for Raspberry Pi.
- Modifying the Device Tree to enable or disable specific hardware.
Real-Time processing and performance optimization
- Use of PREEMPT_RT for real-time applications.
- Optimization of memory and CPU usage.
Debugging and event logging
- Use of dmesg, journalctl, and gdb for error diagnosis.
- Configuration of logs for remote monitoring.
Security
Disable SSH root login and change ports.
- Use of firewall with ufw.
- Mount the SD in read-only mode to avoid corruption in critical systems.
Example to protect SSH:
sudo nano /etc/ssh/sshd_config
Change:
PermitRootLogin no
Port 2222
Final thoughts on this tutorial
As you can see, embedded Linux on Raspberry Pi offers a versatile environment for the development of embedded applications. From basic setup to advanced kernel tuning, there is ample room for exploration and continuous improvement. we invite you to implement these steps and continue on the path of creativity.
Also, check these additional resources:
- Official Raspberry Pi and Embedded Linux documentation
- Raspberry Pi forums and Stack Overflow
- Projects on GitHub and tutorials on online learning platforms
- Raspberry Pi Pico tutorial
- Smart home assistant with Raspberry Pi
- How to run a program on Raspberry Pi
- Home automation with Raspberry Pi
- Build Raspberry Pi projects
