🌍 What is this project
🤔 Why did I make it
⚙️ How does it work
🏗️ Build Instructions
📸 Step 1: Breadboard Assembly
🔌 Step 2: Wiring Chart
💻 Step 3: Software Setup
⚙️ Step 4: Enable Autoboot
▶️ Operation Instructions
🔗 Video Link
🔗 GitHub Link

Published April 23, 2025

BreatheSafe: Pocket-Sized Environmental Monitor

BreatheSafe monitors air quality, temperature, and pressure in real-time, displaying the essentials instantly every time you power up.

IntermediateFull instructions provided56

BreatheSafe: Pocket-Sized Environmental Monitor

Things used in this project

Hardware components

BeagleBoard.org PocketBeagle

M5Stack PM 2.5 SENSOR USB POWER/SHT20 (PMSA003)

MyOctopus i2c Barometric Air Pressure Sensor BMP280

SparkFun Air Quality Breakout - CCS811

ElectroPeak 0.96" OLED 64x128 Display Module

Jumper wires (generic)

Software apps and online services

Cloud9

Hand tools and fabrication machines

Soldering iron (generic)

Story

🌍 What is this project?

This project is a PocketBeagle-powered air quality monitor that reads real-time temperature, pressure, and PM2.5 data, and displays it on a compact OLED screen. It’s designed to boot automatically when powered, requiring no buttons, logins, or user intervention. It acts as a plug-and-play environmental dashboard.

🤔 Why did I make it?

With rising air pollution in cities like Delhi, India, affordable DIY air quality monitors are essential. This project aims to provide an open-source, low-cost solution for measuring air quality in real-time.

I wanted to build a self-contained embedded system that mimics a real-world product that could be used in homes, labs, or classrooms to instantly show environmental data on power-up.

Key goals were:

Use only I²C-based components
Write all logic in Python
Make it autoboot reliably using systemd
Fit everything on a single breadboard powered by USB
Deploy it as a consumer-facing device (no command line!)

This project was also part of my university course assignment - it was the perfect challenge to combine hardware, software, and user experience design.

⚙️ How does it work?

A BMP280 sensor captures temperature and barometric pressure
A PMSA003I sensor measures PM2.5 concentration in the air
An SSD1306 128x32 OLED shows the results
The whole system runs on a PocketBeagle, a tiny Linux computer
When powered, the system auto-runs a Python script using systemd
The OLED shows "Starting...", then displays real sensor readings

The PocketBeagle is powered via USB, but could easily be powered by a battery pack to make this a portable sensor station.

🏗️ Build Instructions

📸 Step 1: Breadboard Assembly

🔌 Step 2: Wiring Chart

All sensors use I²C1:

💻 Step 3: Software Setup

Flash Debian onto the PocketBeagle if needed
SSH into PocketBeagle
Clone your GitHub project:

bash

git clone https://github.com/YOUR_USERNAME/project_01.git
cd project_01

Install requirements

bash

CopyEdit
python3.11 -m pip install -r requirements.txt

⚙️ Step 4: Enable Autoboot

bash

CopyEdit
sudo cp display_readings.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable display_readings.service
sudo systemctl start display_readings.service

OLED should now display "Starting..." followed by readings (or remain blank if PM2.5 = 0).

▶️ Operation Instructions

Power on the PocketBeagle using USB
OLED will show:Starting...
After 5 seconds, if PM2.5 is non-zero24.9 C 1014.8 hPa PM2.5: 6
If PM2.5 = 0, the screen remains blank

🔗 Video Link

https://drive.google.com/file/d/1_cilT0PCqG_cwNbC9SbayeKhWl5p9YLm/view?usp=sharing

🔗 GitHub Link

https://github.com/arjunkannan131/EDES301/tree/main/project_01

Code

Final code

import time
from smbus2 import SMBus
from bmp280 import BMP280
import board
import busio
import adafruit_ssd1306
from PIL import Image, ImageDraw, ImageFont

# I2C Setup
i2c_display = busio.I2C(board.SCL, board.SDA)
bus = SMBus(1)

# Display config
WIDTH = 128
HEIGHT = 32
display = adafruit_ssd1306.SSD1306_I2C(WIDTH, HEIGHT, i2c_display, addr=0x3C)

# Drawing setup
image = Image.new("1", (WIDTH, HEIGHT))
draw = ImageDraw.Draw(image)
font = ImageFont.load_default()

# Clear and show "Starting..." immediately
draw.rectangle((0, 0, WIDTH, HEIGHT), outline=0, fill=0)
draw.text((0, 10), "Starting...", font=font, fill=255)
display.image(image)
display.show()

# Sensor setup
bmp280 = BMP280(i2c_dev=bus)
PMSA003I_ADDR = 0x12

# Read PM2.5
def read_pm25(bus):
    try:
        data = bus.read_i2c_block_data(PMSA003I_ADDR, 0x00, 32)
        pm2_5 = (data[12] << 8) | data[13]
        return pm2_5
    except:
        return 0

# Main
def main():
    print("Warming up sensors...")
    time.sleep(5)

    try:
        temperature = bmp280.get_temperature()
        pressure = bmp280.get_pressure()
    except:
        temperature, pressure = 0.0, 0.0

    pm2_5 = read_pm25(bus)

    if pm2_5 != 0:
        draw.rectangle((0, 0, WIDTH, HEIGHT), outline=0, fill=0)
        draw.text((0, 0), f"{temperature:.1f} C", font=font, fill=255)
        draw.text((0, 10), f"{pressure:.1f} hPa", font=font, fill=255)
        draw.text((0, 20), f"PM2.5: {pm2_5}", font=font, fill=255)
        display.image(image)
        display.show()
        print("Displayed:", temperature, pressure, pm2_5)
    else:
        print("PM2.5 is 0  no display triggered.")

if __name__ == "__main__":
    main()

BreatheSafe: Pocket-Sized Environmental Monitor

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

🌍 What is this project?

🤔 Why did I make it?

⚙️ How does it work?

🏗️ Build Instructions

📸 Step 1: Breadboard Assembly

🔌 Step 2: Wiring Chart

💻 Step 3: Software Setup

⚙️ Step 4: Enable Autoboot

▶️ Operation Instructions

🔗 Video Link

🔗 GitHub Link

Schematics

Schematic

Code

Final code

Credits

Arjun Kannan

Comments

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BreatheSafe: Pocket-Sized Environmental Monitor

BreatheSafe: Pocket-Sized Environmental Monitor

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

🌍 What is this project?

🤔 Why did I make it?

⚙️ How does it work?

🏗️ Build Instructions

📸 Step 1: Breadboard Assembly

🔌 Step 2: Wiring Chart

💻 Step 3: Software Setup

⚙️ Step 4: Enable Autoboot

▶️ Operation Instructions

🔗 Video Link

🔗 GitHub Link

Schematics

Schematic

Code

Final code

Credits

Arjun Kannan

Comments

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