Python and Hardware Control | Raspberry Pi Tutorial

Why Python Is the Default Superpower

Python is not the only good language on Raspberry Pi, but it is usually the fastest route from idea to working prototype.

It is strong for:

automation scripts
GPIO control
small web apps and APIs
camera and sensor integrations
data logging and dashboards

Set Up a Clean Python Workflow

sudo apt install -y python3-pip python3-venv python3-dev
mkdir -p ~/projects/blink-demo
cd ~/projects/blink-demo
python3 -m venv .venv
source .venv/bin/activate
pip install --upgrade pip

Recommended Library Categories

Need	Good starting point
beginner-friendly GPIO	`gpiozero`
lower-level GPIO control	`lgpio` or `gpiod`-based tooling depending on stack
HTTP APIs	`FastAPI` or Flask
scheduling simple jobs	`APScheduler` or cron
camera and imaging	`picamera2`, OpenCV
MQTT and IoT messaging	`paho-mqtt`

First Example: Blink an LED

Wire an LED to a GPIO pin with a resistor and use gpiozero.

pip install gpiozero

from gpiozero import LED
from time import sleep

led = LED(17)

while True:
    led.on()
    sleep(1)
    led.off()
    sleep(1)

Second Example: React to a Button

from gpiozero import Button, LED
from signal import pause

button = Button(27, pull_up=True)
led = LED(17)

button.when_pressed = led.on
button.when_released = led.off

pause()

Structure Your Project Early

garden-monitor/
├── app/
│   ├── main.py
│   ├── sensors.py
│   ├── storage.py
│   └── web.py
├── requirements.txt
├── .env
└── systemd/
    └── garden-monitor.service

This is better than one giant script once the project becomes real.

Turning a Script Into a Service

Example systemd unit:

[Unit]
Description=Garden Monitor
After=network-online.target

[Service]
User=your-user
WorkingDirectory=/home/your-user/projects/garden-monitor
ExecStart=/home/your-user/projects/garden-monitor/.venv/bin/python -m app.main
Restart=always

[Install]
WantedBy=multi-user.target

Then enable it:

sudo cp systemd/garden-monitor.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now garden-monitor

Patterns That Work Well on Pi

Pattern	Why it works
Poll sensor, write to local file or DB, expose small API	Simple and robust
Separate collection loop from web UI	Easier debugging
Use env vars or config file for pin numbers and thresholds	Hardware changes without code edits
Keep long-running loops restartable	Pi projects do eventually crash

Example Automation Script

Turn on a fan relay when CPU temperature is high.

from gpiozero import OutputDevice
from time import sleep
from subprocess import check_output

fan = OutputDevice(18, active_high=True, initial_value=False)


def cpu_temp_c() -> float:
    raw = check_output(['vcgencmd', 'measure_temp'], text=True)
    return float(raw.split('=')[1].split("'")[0])


while True:
    temp = cpu_temp_c()
    fan.value = temp >= 60
    sleep(10)

When to Use Another Language

Language	Good reason to choose it
Go	Single binary services, low memory web backends, easy deployment
Rust	Performance-critical or reliability-critical services
Node.js	If your team already lives in JavaScript
C/C++	Tight hardware integration or performance-sensitive code

Python remains the best default until you have a strong reason otherwise.

Next Step

Move to 05-electronics-gpio-and-sensors.md to learn safe hardware patterns that keep your software projects from frying components.