Note

Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

Why Join?

• Expert Support: Solve post-sale issues and technical challenges with help from our community and team.

• Learn & Share: Exchange tips and tutorials to enhance your skills.

• Exclusive Previews: Get early access to new product announcements and sneak peeks.

• Special Discounts: Enjoy exclusive discounts on our newest products.

• Festive Promotions and Giveaways: Take part in giveaways and holiday promotions.

👉 Ready to explore and create with us? Click [here] and join today!

4.1.1 Magnetic Induction Alarm System

Introduction

When you get a precious vase, you can make a magnetic induction alarm system for it, no matter who moves it, you can hear the alarm in time.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Raphael Kit	337	Raphael Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION	PURCHASE LINK
GPIO Extension Board	BUY
Breadboard	BUY
Jumper Wires	BUY
Resistor	BUY
Buzzer	BUY
Transistor	BUY
Reed Switch Module	BUY

Schematic Diagram

T-Board Name	physical	wiringPi	BCM
GPIO17	Pin 11	0	17
GPIO27	Pin 13	2	27

Experimental Procedures

Step 1: Build the circuit.

Step 2: Get into the folder of the code.

cd ~/raphael-kit/python-pi5

Step 3: Run.

sudo python3 4.1.6_MagneticAlarmSystem_zero.py

If the reed switch is affected by the magnet (for example, the reed switch is placed on the base and the magnet is placed in the vase), the object is safe. At this time, the reed switch is in the closed state, and the buzzer is silent. After removing the magnet (such as the vase being stolen), the reed switch is not affected by the magnetic, the switch opens, and the buzzer sounds an alarm.

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python-pi5. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3
from gpiozero import Buzzer, Button
import time

# Initialize the buzzer on GPIO pin 27
buzzer = Buzzer(27)
# Initialize the reed switch on GPIO pin 17 with pull-up resistor enabled
reed_switch = Button(17, pull_up=True)

try:
    while True:
        # Check if the reed switch is pressed
        if reed_switch.is_pressed:
            # Turn off the buzzer if reed switch is pressed
            buzzer.off()
        else:
            # If reed switch is not pressed, beep the buzzer
            buzzer.on()
            time.sleep(0.1)  # Buzzer on for 0.1 seconds
            buzzer.off()
            time.sleep(0.1)  # Buzzer off for 0.1 seconds

except KeyboardInterrupt:
    # Turn off the buzzer when the program is interrupted (e.g., keyboard interrupt)
    buzzer.off()
    pass

Code Explanation

1. This imports the necessary classes Buzzer and Button from the gpiozero library, and the time module from Python’s standard library.

   #!/usr/bin/env python3
   from gpiozero import Buzzer, Button
   import time
   

2. The Buzzer object is linked to GPIO pin 27, and a Button (acting as a reed switch) is connected to GPIO pin 17 with the pull_up=True argument, enabling the internal pull-up resistor.

   # Initialize the buzzer on GPIO pin 27
   buzzer = Buzzer(27)
   # Initialize the reed switch on GPIO pin 17 with pull-up resistor enabled
   reed_switch = Button(17, pull_up=True)
   

3. The try block contains an infinite loop (while True) checking the state of the reed switch. If pressed (is_pressed), the buzzer is turned off. Otherwise, the buzzer beeps (0.1 seconds on, 0.1 seconds off).

   try:
       while True:
           # Check if the reed switch is pressed
           if reed_switch.is_pressed:
               # Turn off the buzzer if reed switch is pressed
               buzzer.off()
           else:
               # If reed switch is not pressed, beep the buzzer
               buzzer.on()
               time.sleep(0.1)  # Buzzer on for 0.1 seconds
               buzzer.off()
               time.sleep(0.1)  # Buzzer off for 0.1 seconds
   

4. The except block handles a KeyboardInterrupt (like a Ctrl+C in the terminal) to turn off the buzzer safely.

   except KeyboardInterrupt:
       # Turn off the buzzer when the program is interrupted (e.g., keyboard interrupt)
       buzzer.off()
       pass