Édouard's Raspberry Pi Course

edouard.md

Édouard's Raspberry Pi Course

Tags: Raspberry Pi, Electronics

Raspberry Pi For Beginners - 2021 Complete Course | Udemy

• The current limit for the Raspberry Pi is near 15 mA.
• When using an infinite loop, use time.sleep to consume less CPU usage.
• hostname -I for the IP address on the network.
• df -h for the available space on the SD card.
• sudo raspi-config for more Rasp configs.
• Use yagmail to send and receive emails (SMTP).
• You can use systemd to start your app when the Raspberry Pi boots up.

   [Unit]
   Description = Program that detects movements, takes a photo and sends an email with it
   After=multi-user.target
   
   [Service]
   ExecStart=/user/bin/python3 /home/pi/Documents/python_programs/project_step4.py
   User=pi
   
   [Install]
   WantedBy=multi-user.target

  • Then sudo systemctl enable project.service
• Taking photos: raspistill -o camera/img.jpg
  • You can also use rotation, width and height arguments.
  • And you can also record videos with raspivid
  • In Python:

   import picamera
   
   camera = PiCamera()
   camera.resolution = (1280, 720)
   camera.rotation = 180
   time.sleep(2)
   
   file_name = "path/to/file"
   camera.capture(file_name)
   print("Done.")
   
   # Or:
   camera.start_recording(file_name)
   camera.wait_recording(10)
   camera.stop_recording()

Python Management

• pip3 list to list all of the installed packages.
• except KeyboardInterrupt: captures the Ctrl + C exception.

# Use `"w"` to write
with open("/home/pi/text_file", "r") as f:
    # print(f.read())
	for line in f:
	    print(line)

if os.path.exists("/home/pi/text_file"):
    print("File exists")
	os.remove("/home/pi/text_file")

Web Server

from flask import Flask
import RPi.GPIO as GPIO

BUTTON_PIN = 26

GPIO.setmode(GPIO.BCM)
GPIO.setup(BUTTON_PIN, GPIO.IN)

app = Flask(__name__)

@app.route("/")
def index():
    return "Hello from Flask"
	
@app.route("/push-button")
def push_button_state():
    if GPIO.input(BUTTON_PIN) == GPIO.HIGH:
		return ""
	else:
	    return "Button is not pressed"

app.run(host="0.0.0.0", port=8500)