4.1.6 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/

Step 3: Run.

sudo python3 4.1.6_MagneticAlarmSystem.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. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3
import RPi.GPIO as GPIO
import time

BeepPin = 27
ReedPin = 17

def setup():
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(BeepPin, GPIO.OUT, initial=GPIO.HIGH)
    GPIO.setup(ReedPin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

def loop():
    while True:
        if GPIO.input(ReedPin) == 0:
            GPIO.output(BeepPin, GPIO.HIGH)
        else:
            GPIO.output(BeepPin, GPIO.LOW)
            time.sleep(0.1)
            GPIO.output(BeepPin, GPIO.HIGH)
            time.sleep(0.1)

def destroy():
    GPIO.output(BeepPin, GPIO.HIGH)
    GPIO.cleanup()

if __name__ == '__main__':
    setup()
    try:
        loop()
    except KeyboardInterrupt:
        destroy()

Code Explanation

def loop():
    while True:
        if GPIO.input(ReedPin) == 0:
            GPIO.output(BeepPin, GPIO.HIGH)
        else:
            GPIO.output(BeepPin, GPIO.LOW)
            time.sleep(0.1)
            GPIO.output(BeepPin, GPIO.HIGH)
            time.sleep(0.1)

We judge the state of the reed switch in the main loop. If the reed switch is closed, the buzzer does not work; otherwise, the buzzer beeps.