Linux Embedded Power Control Unit (PCU)

University Capstone Project — Open source Linux embedded power control unit with a Python REST API for control and monitoring.

This project is a comprehensive solution for controlling power outlets and monitoring power consumption via a Raspberry Pi. It features a custom hardware interface, a Python backend, and a RESTful API designed for reliability and ease of use in embedded environments.

Features

• Smart Control — independent toggle of 8 relays via GPIO.
• Real-time Monitoring — voltage, current, and power measurement via MCP3008 ADC.
• REST API — full programmatic control using Flask and JWT authentication.
• System Optimization — RAM disk storage for high-frequency logs to prevent SD card corruption.
• Automated Services — self-healing background services managed via cron and Pipenv.

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Installation Guide

Follow these steps to set up the Power Control Unit from a fresh Raspberry Pi installation.

1. OS Preparation

1. Use Raspberry Pi Imager to write Raspbian Lite OS on your SD card.
2. Connect the Pi to a screen and keyboard for initial setup.

2. Raspbian Configuration

Update the system:

sudo apt-get update
sudo apt-get upgrade

Run the config tool:

sudo raspi-config

• System Options — set a new password and the PCU hostname.
• Interface Options — enable SPI and SSH.
• Localisation — set local system time (critical for logs).
• Reboot — restart the system.

3. Install Dependencies

Install Python pip, network utils, and bridge-utils:

sudo apt-get install python3-pip bridge-utils
pip3 install pipenv

4. Mount a RAM Partition (Optimization)

To prevent SD card wear from frequent log writes, create a temporary RAM disk.

Create the directory:

mkdir /var/tmp

Edit fstab:

sudo nano /etc/fstab

Add this line at the end (400MB RAM disk):

tmpfs /var/tmp tmpfs nodev,nosuid,size=400M 0 0

Mount the disk:

sudo mount -a

5. Sync PCU Files

Clone the repository or copy files via SCP. For Windows (using SCP), replace {hostname} with your Pi hostname:

scp -prq software/pcu pi@{hostname}.local:/home/pi

Set up the Python environment:

cd pcu
python3 -m pipenv install

6. Setup Auto-Launch

Use cron to launch PCU services at boot:

crontab -e

Add these commands at the end of the file:

@reboot cd /home/pi/pcu && python3 -m pipenv run init_gpio > /home/pi/gpio_log.txt
@reboot cd /home/pi/pcu && python3 -m pipenv run adc      > /home/pi/adc_log.txt
@reboot cd /home/pi/pcu && python3 -m pipenv run serve    > /home/pi/serve_log.txt
@reboot cd /home/pi/pcu && python3 -m pipenv run logger   > /home/pi/logger_log.txt

7. Network Bridge

Add ethernet bridge configuration to the end of /etc/network/interfaces:

auto br0
iface br0 inet dhcp
    bridge_ports eth0 eth1

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Documentation

• Hardware — Hardware Pinout
• API — API Documentation