Efficient power management is crucial for embedded systems, particularly for industrial edge devices like the ALPON X4. Optimizing power consumption extends operational time, reduces thermal output, and enhances system reliability. This document provides a comprehensive guide to power-saving techniques for the ALPON X4.

Basic Power Saving

These simple steps can help reduce power consumption on your device.

1. Disabling WiFi If Not Used

If WiFi is not needed, turning it off can save power.

sudo rfkill block wifi

2. Disabling HDMI

If you do not need HDMI output, you can disable it to save power. Open the Raspberry Pi configuration menu:

sudo raspi-config

This menu also allows various other configurations.

3. Disabling Not Used Services

sudo systemctl disable bluetooth.service
sudo systemctl disable lightdm
... etc.

4. Disabling USB Ports

Shutting down unused USB ports can help reduce power consumption:

echo '1-1' | sudo tee /sys/bus/usb/drivers/usb/unbind

3. Stopping Background Applications

Terminating unnecessary applications and background services reduces CPU load. Note: Avoid terminating any processes started by the 'sixfab' user.

sudo killall [name]

Expert Power Saving

For advanced users, here are additional power-saving techniques that can significantly reduce power consumption on your device. Please note that some of these steps may impact system stability or performance, so proceed with caution.

1. Underclocking and Undervolting the CPU

Reducing the CPU’s clock speed and voltage can save energy, but it may cause instability. Ensure you test thoroughly and monitor system performance.

2. Managing CPU Cores Based on System Load

Dynamically enabling or disabling CPU cores according to system load can conserve power during low activity periods.

Example Code:
Save the following script as /usr/local/bin/manage-cores.sh to manage CPU cores based on load:

#!/bin/bash
// Disable cores when load is low
if [ $(cat /proc/loadavg | cut -d ' ' -f1 | cut -d '.' -f1) -lt 2 ]; then
    echo 0 > /sys/devices/system/cpu/cpu3/online
    echo 0 > /sys/devices/system/cpu/cpu2/online
fi
// Enable when load increases
if [ $(cat /proc/loadavg | cut -d ' ' -f1 | cut -d '.' -f1) -gt 4 ]; then
    echo 1 > /sys/devices/system/cpu/cpu2/online
    echo 1 > /sys/devices/system/cpu/cpu3/online
fi

3. Setting the CPU Governor

Setting a conservative CPU governor allows the system to adjust the CPU frequency dynamically, depending on the load, which helps in balancing performance and power savings.

Install and configure CPU frequency utilities:

sudo apt-get install cpufrequtils
sudo cpufreq-set -g conservative
echo 'GOVERNOR="conservative"' | sudo tee /etc/default/cpufrequtils

These expert-level strategies can help optimize power usage, especially in environments where battery life and power efficiency are priorities.

By following these power-saving practices, you can optimize energy efficiency while maintaining system functionality. For mission-critical applications, always test changes before applying them to production systems.