Construction of a Luggage Security Alarm Circuit System

Luggage Security System

During traveling on the bus or the train, we carry many things like luggage and costly things, but we have the fear that somebody might steal the luggage. So to guard our luggage, we usually lock our luggage through the old methods with the help of lock and chain. After all these, we still stay in fear that any thief may break the chain and take away all the valuable things. To overcome this problem, here is a system, namely luggage security alarm circuit which is based on the NAND gate. The main aim of this system is to generate an alarm when any unauthorized person tries to steal your luggage. This system is very useful when you travel in the night time. Another application of this luggage security alarm system is, you can use in your home for the security from the theft.

Luggage Security Alarm Circuit System

The project is built with some required electrical and electronic components like CD4011, LDR, capacitor, variable resistor, relay, and transistor.

Relay Switch

The relay is an electromagnetic switch device, used to separate two circuits electrically and attach them magnetically. These are very useful devices and let one circuit make another circuit ON while they are totally separate. They are frequently used to interface the electrical and electronic circuits which work at very high voltage. For instance, a relay is used to make a 5V DC battery circuit to change a 230V AC mains circuit. Therefore a sensor circuit can drive an electric bulb or a fan.

Relay Switch

Diode 1N4001

The 1n4001 diode is a rectifying device, that conducts simply from anode to cathode. This diode acts as an open circuited when the flow of current is from the cathode to anode. 1N4001 has a low forward voltage drop and a high surge current capability. It includes of diffused PN-junction and also has 5µA low reverse leakage current, and the DC blocking voltage is 50V. The cathode terminal of the diode is recognized by a bar symbol on diode case and the remaining terminal is the anode (p).

Diode 1N4001

Resistor

The resistor is a passive component used for controlling current in a circuit. Its resistance is given by the fraction of the voltage applied across its terminals to the current flowing through it. Thus, a specific value of the resistor, for static voltage, restricts the flow of current through it. They are universal in electronic circuits.

Resistor

Capacitor

A capacitor is a passive component used to store charge. The charge ‘q’ stored in a capacitor is the product of its capacitance and the voltage applied to it. The capacitor offers endless reactance to zero frequency so they are utilized for allowing the AC signals and blocking DC components. The capacitor undergoes over a recursive cycle of charging & discharging in AC circuits where the current and voltage across it depends on the RC time constant. For this reason, these are used for leveling power supply differences. Another include connecting the various stages of the audio system, changing in radio circuits etc.

Capacitor

2N2222 Transistor

The 2N2222 transistor is an NPN BJT-transistor. It is used for low-power switching and amplification applications. These transistors are designed for high-speed switching applications at CC (collector current) up to 800mA. It offers current gain over a wide range of CC (collector current), low saturation voltage and low leakage currents. The emitter terminal of this transistor is specified by an expanded edge in the transistor case. The base terminal is adjacent to the emitter terminal while collector-terminal lies in the other extreme of the casing.

Transistor 2N2222

Luggage Security Alarm Circuit System Working

It produces a threatening beep when somebody tries to open the locker. To know the working you must know about the truth table of NAND-gate which is as follows-

NAND Gate Truth Table

The above truth table of NAND gate shows that the o/p will stay HIGH when the i/p signal is LOW. If both the signals ho HIGH, then, in that case, the o/p will be LOW.

The o/p of the circuit depends on Pin-5. When the power supply is given to the circuit the voltage at pin-5 is zero as the loop is complete. So, the voltage at pin-4 becomes HIGH which connects to the pins 1&2 which are also high. As the truth table says that if both the i/ps are high, then the o/p is low. So we will get LOW at pin-3 of gate-1 which is interfaced to pins 12 and 13 for making them LOW. Therefore, pin-11 goes HIGH making pins 8 & 9 also HIGH and the voltage at pin-10 as LOW. As a result, transistor allied to it through a resistor will not be strengthened and we will not get the alarm.

Luggage Security Alarm Circuit System

Now imagine someone trying to steal the luggage, therefore, the loop which is connected to the luggage will breaks. When loop breaks pin 5 & 6 goes high and opposite action takes place. As a result, pin-10 will become higher, and the transistor will start conducting, then an alarm will generate the sound. This alarm sound will not turn off until the loop is intact again.

In the above luggage security system circuit, depending on the rating of the relay, the battery used can be 6-15V. The buzzer can also be connected directly without the need of a Relay. A relay can be used if the alarm works on AC supply an extra isolation would be required from unexpected current spikes. A diode can be used by the relay because any reverse voltage spike can lead to damage the circuit at the source.

Advantages of Luggage Security System

The advantages of a luggage security system include the following

• This security system is used to guard your valuable things when someone tries to steal by generating an alarm sound.
• It can be operated with 3V, so the power consumption is very less.
• It is portable while traveling because it has fewer components

From the above information, we can conclude that this electronic project kit can be used to stop the burglary attempt as when somebody tries to steal the luggage.We hope that you have got a better understanding of this concept. Furthermore, any doubts regarding this concept or to implement any security system based projects. Please give your valuable suggestions by commenting in the comment section below. Here is a question for you, What are the other applications of the luggage security system?