Free Electronic Circuit Schematics » Security circuit

Intelligent Wire Loop Alarm Circuit With IC

admin — Fri, 11 Feb 2011 06:57:17 +0000

Wire Loop Alarm Circuit

Integrated circuit anti-theft alarm system, wire or other lack of a simple circuit.
When the lack of wires or cords lacking. MOSFET, it is working or has input voltage at pin G and thus it has a high current flows through the pin D-S that Micro piezo siren was so loud.

Electronic Part List

R1 100K 1/2W 1% Resistor
R2, R4 10K 1/2W 1% Resistor
R3 1 Meg 1/2W 1% Resistor
C1, C3 0.1uF Ceramic Disc Capacitor
C2 0.01uF Ceramic Disc Capacitor
IC1 4001UBE Quad 2-i/p NOR Gate
Q1 MPSA14 Low Power NPN Transistor
SIREN Micro piezo siren 12V DC 150mA, 110dB @ 1M
LOOP See “Notes”
The loop can be any type of hookup wire, with a maximum resistance of about 90K. Using very thin wire (40AWG, for example) will make a very sensitive trip wire, but will shorten the distance it can be strung due to the high resistance.

The siren can be replaced with a relay to drive external loads.

Digital Touch On/Off Switch Circuit With CD4001

admin — Tue, 23 Nov 2010 09:49:46 +0000

digital touch circuit

Specially designed to showcase animation useful for many types of controls, the purpose of this circuit is to animate the windows using a capacitive sensor placed behind a banner postcard-like. The card is placed against the window pane, and the visitor can activate the relay placing his hand on the paper

This touches on a simple switch of the new circuit. Use the digital chip is a major equipment and supply 9V voltage low-power single. Metal single-use, works with character on and off. In the first time when I touch, but enough to extinguish the second time. The circuit consists of IC CD4001 take a finger into an electrical signal by the digital signal for change. The CD4020 circuit chip has two or divide the circuit for two. Then come forward to next unit load transistor.

Security Door Locks Circuit with IC 4022

admin — Fri, 19 Nov 2010 08:52:24 +0000

security door circuit

This circuit can apply to many hobby project .

An electronic door lock circuit different, which is very simple, and we do not need lots of materials for the UN it is produced. The key to a line of code should be strengthened by the straight line, so you optocupler Enable IC1.

If by mistake and stepped spy who does not belong in combination, then the block is trapped. To recover, we adjust the unit for the block, you must press the switches S1 or S10 for correct the password.

The external reset button S1 is inside and lock the S10,

The Code of the circuit, it is connected, and IC4022 and can be easily modified by changing the connections in the keyboard switch.

The Q2 BD679 can lead to everything, etc. external circuit relay events, while providing electrical insulation of the circuit due. In addition, the circuit can be powered by a 9V ..

Electronic Part List

R1-7=4.7K ohm
R8=15Kohm
R9=1Mohm
R10-13=10Kohm
R11=100 ohm
R12=220 Kohm
R14=1.2Kohm
D1-2=1N4148
D3=RED LED 3mm
IC1=4022
C1-3=100nF 100V
C2=4.7uF 25V
Q1=BS170
Q2=BD679
S1-10=Push button or keyboard

Toxic Gas Detector and Alarm Circuit with TGS813

admin — Sun, 24 Oct 2010 07:20:39 +0000

toxic gas detector circuit

The danger always exists, when the fuel gases such as propane or gas are confined to a small area. The alarm of toxic gases figs. 1-45 utilizes a tin-oxide-semiconductor. A coil of thin wire heated by a battery 12 V via IC1 and IC2, which pulses the voltage to the coil of the sensor, saving a significant amount of energy. Diode Zener Dl provides a constant voltage to the filament coil sensor. resistance of the sensor reduces the sensor is exposed to toxic gases such as hydrogen, carbon
carbon monoxide and propane. To reduce the resistance of the sensor, the SCR gate voltage increases. When the gate threshold voltage is reached, the SCR fires and a buzzer alarm is activated. Once activated, the bell and the switch S1 should be used to reset the alarm. Since the sensor has a good deal of thermal inertia, S1 must be off or open for about three or four minutes after the initial activation, allowing the sensor to stabilize, thus avoiding false alarms. R7 sensitivity control set to the desired value, before the activation of SCR.

The toxic gas alarm is sensitive to less than 100 ppm of carbon monoxide. This alarm is useful for simple gas boats, sheds and cabins. You could save a life. Some of the companies listed in the Appendix to offer plans and kits for various toxic gas sensors.

Part List
Part Description

C1 0,01-MFD, 25-V capacitor (disc)
1 9-V zener diode D1 (NTE139A)
1 D2 4-V diode zener (NTE5068A)
1 SCR D3 (NTE5408)
1 Q1 Transistor 2N2222
U1 1 CD4013 CMOS flip-flop
1 U2 CD4049 CMOS Inverter Hex
1 siren piezo BUZ 6-9V
1 S1-TGS203 toxic gas sensor (Figaro or equivalent)

TGS812

5 zone anti theft circuit

admin — Mon, 11 Oct 2010 14:25:31 +0000

5 zone anti-theft circuit

The anti-theft circuit is simply alarm points 5 points (zone1 – zone5) , If the work which will be controlled or buzzer sound the Contact add relay RLA1.

Overview
The circuit was built to trigger a small office or home environment, which consists of seven-segment LED display from which zone the alarm, while adjusted five independent zones

Function Detail

Zone – refers to input a control unit card from a protection circuit that the alarm system may comprise in separate zones according to independent security function, the medical fire, intrusion or monitoring of critical conditions shall
7-segment – is a form of electronic display device for displaying a decimal number that is an alternative to the more complex dot-matrix screens are also known as seven-segment display is
Declaration of the circuit
The design of the circuit was described in the operation of three CMOS buffers, built by the suffix B. They were used because the profit is very high, are sensitive to changes in the parameters of the oscillator circuit and are less stable unbuffered IC. This series of CMOS chips are generally characterized by small variations of the power supply has very high input impedance, it does not affect the part of the circuit in which it is connected, outputs can sink and the source of only 1 mA maintain the proper output voltage to CMOS inputs can drive up to 50 inputs, the signal propagation time soon with the right degree of tension, has a frequency of up to 1 MHz and has a very low consumption.

The function of the circuit, it is important to remember that all areas are from 1 to 5 generally closed by means of alarm contacts. Zone 2-5 direct or immediate areas in which delays are not present when the alarm is triggered while the zone is a zone as a time of work that you want in the main entry and exit point of a building, where the functions S1 as the set and reset button, usually a key-type metal. Capacitors C1 to C5 provide radio frequency protection, as long wires were used. C7 and resistor R14 function as a transient suppressor, in which they react to sudden or momentary overvoltage.

The capacitor C6 is charged through R11 when the switch is on, what seems like a delay of about 30 seconds. The delay time can by changing the value of a C6 or R11 can be varied. LED 6 May set the outside visual identification that the system was adjusted to provide. If the system, 6-LED lights will be activated once the duration of the delay is over. The area triggers an alarm when a contact open after setting the plant. The hidden switch back must be enabled to transfer the alarm to prevent the entrance of the building. Thus, the entry timer and capacitor C6 discharges. The switch of return can be located anywhere in a door frame, but obviously is not visible and must be hidden. The alarm is triggered when the panic will set down. RLA2 controls the siren or horn RLA1 while for detention, because the relay is energized.

Application
Seven-segment displays are widely used in digital watches, used electronic counters, digital tools, equipment and other electronic equipment to display numerical information. In general, LEDs can be used as indicators and signs, lighting and lighting in non-visual light sources to the circuit systems.The machine vision is used in high-security premises such as offices, buildings used to be government and government-guaranteed places to prevent unauthorized access.

New Fire Alarm Circuit with TDA2002

admin — Sun, 06 Jun 2010 05:32:58 +0000

New fire alarm circuit

This system prevents users from fire. It depends on the smoke, which consists of a fire.

When the smoke takes the bulb and LDR, the amount of light falling LDR decreases.

This causes the resistance LDR increases, and voltage transistor base pulled high which makes the provision of COB (chip on board) will be completed. Different ears available in the market to create different sounds.
COB select depends on the user. Signal generated by COB supplemented by audio amplifier.

Under this system, audio power amplifier is connected to some IC TDA 2002. Sensitivity of the system depends on the distance between the lamp and LDR, and create a pre-VR1. This may be a lamp and LDR at an appropriate distance, you can toggle between pre-VR1, to obtain optimal sensitivity.
ON / OFF switch is proposed to contain the system or outside.

DEW Sensor Circuit with LM358N

admin — Sat, 05 Jun 2010 05:25:35 +0000

DEW sensor circuit

Dew (condensed moisture) ad- versely affects the normal per- formance of sensitive electronic devices.A low-cost circuit described here can be used to switch off any gadget automatically in case of excessive humidity.At the heart of the circuit is an inexpensive (resistor type) dew sensor element.

Although dew sensor elements are widely used in video cassette players and recorders, these may not be easily available in local market. However, the same can be procured from authorised service centres of reputed companies. The author used the dew sensor for FUNAI VCP model No. V.I.P. 3000A (Part No: 6808-08-04, reference no. 336) in his prototype. In practice, it is observed that all dew sensors available for video application possess the same electrical characteristics irrespective of their physical shape/size, and hence are interchangeable and can be used in this project. The circuit is basically a switching type circuit made with the help of a popular dual op-amp IC LM358N which is configured here as a comparator.

(Note that only one half of the IC is used here.) Under normal conditions, resistance of the dew sensor is low (1 kilo-ohm or so) and thus the voltage at its non-inverting terminal (pin 3) is low compared to that at its inverting input (pin 2) terminal. The corresponding output of the comparator (at pin 1) is accordingly low and thus nothing happens in the circuit.

When humidity exceeds 80 per cent, the sensor resistance increases rapidly. As a result, the non-inverting pin becomes more positive than the inverting pin. This pushes up the output of IC1 to a high level. As a consequence, the LED inside the opto-coupler is energised.

At the same time LED1 provides a visual indication. The opto-coupler can be suitably interfaced to any electronic device for switching purpose. Circuit comprising diode D2, resistors R5 and R6 and capacitor C1 forms a low-voltage, low-current power supply unit. This simple arrangement obviates the requirement for a bulky and expensive step-down transformer.

Air Flow Detector Circuit

admin — Thu, 03 Jun 2010 05:09:58 +0000

air flow detector circuit

Parts List

R1 100 Ohm 1/4W Resistor
R2 470 Ohm 1/4W Resistor
R3 10k 1/4W Resistor
R4 100K 1/4W Resistor
R5 1K 1/4W Resistor
C1 47uF Electrolytic Capacitor
U1 78L05 Voltage Regulator
U2 LM339 Op Amp
L1 #47 Incandescent lamp with glass removed (See “Notes”)
D1 LED

Notes:
1. The glass will have to be removed from L1 without breaking the filament. Wrap the glass in masking tape and it in a vise. Slowly crank down until the glass breaks, then remove the bulb and carefully peel back the tape. If the filament has broken, you will need another lamp.

Combination Lock circuit with IC4013

admin — Thu, 25 Jun 2009 01:18:11 +0000

Combination Lock circuit

This circuit is very basic to build. To open a the lock which is connected to the K1 Load. you must press each momentary switch in the correct sequence. The sequence used in this circuit is S1,S2,S3,S4. If any of the other switchs are pressed the circuit will reset and you will need to start over. Depending on how you wire the switchs, you can use any 4 switch combination

Motorcycle Alarm Circuit and PCB for Prevent steal.

admin — Tue, 16 Jun 2009 13:23:21 +0000

This project is prevented steal circuit which be kit to be easy the system is simple. but We thinks the project should be help to protect your motorcycle or accessories. This principle is simple be the system Close Wire Loop.

: motorcycle alram circuit

The circuit is going to make a noise to warn that circuit turn , with the circuit used power electric energy while standby very low 0.5 uAmp. When relay working as a result use current about 70mAmp . The usability can use in an automobile,house door, leak round a house or the other. That time an electric line turn system , Relay command sent beep danger circuit work immediately.