This Rental Car Alarm Mode

VIVAnews -for you, the entrepreneur must present more car rental alert. The action of the crime of theft of motor vehicles with the modus operandi of the world's first driver-vehicle rental is now central to occur.

Not only that, the perpetrator also often act by pretending to be applying for a driver and then bring the blurry car. In addition, the offender also falsified identity to darken the vehicle rented.

Based on data in units of the expertise of the General Directorate of Criminal Ranmor Polda Metro Jaya felony theft of four-wheeled motor vehicles during the period of June 2011, as much as 24 vehicles were stolen from the car rental company.

"Modusnya vary, first there was the perpetrator who commits the world's first driver of a vehicle lease, anyone applying for a driver and then his car taken so blurred, there's also a rental vehicle, bringing hazy embezzlement of the vehicle," said Kasubdit Ranmor Polda Metro Jaya Suyudi Aryo Seto when talking with VIVAnews.com, Thursday, June 23, 2011.

Then how to anticipate such modus operandi? According to Suyudi prevention efforts can be made the owner of the vehicle is known early life a personal driver to be recruited. "He Should know the identity of and other. At least the police can do investigations in case of theft, "he said.

Not only that, the installation of the Global Positioning System (GPS) is very necessary for vehicles to be direntalkan. "GPS need to be especially for rental cars and this facilitates the work of the police," he added.

Previously, a unit of the Directorate of Criminal Expertise Ranmor General Polda Metro Jaya uncover three specialist car theft syndicates with the rental evidence as much as 24 units.

Of the three syndicates thieves there are seven suspects, including thieves and penadahnya. Principal initials DF, SY and the US (residivis), FZ with mode rent a car, as well as AR, NARRATED by way of anesthetized driver and Charter a woman cast as penadah, ET.

Police arrested the perpetrators and the exhibits area pencuriannya results Jakarta, Bekasi (West Java), Central Java and East Java. Stolen cars to the perpetrator to sell at a price range of Rp20 penadah million-Rp30 million per unit with a falsified Letter number sign Vehicle (VEHICLE LICENSE) and the owner of a motor vehicle (REGISTRATION,).

As known, during the period of 2010 Polda Metro Jaya noted there has been a four-wheeled curanmor 1.598 with the highest theft rates in Jakarta as 411 cases. As for the period January-April 2011 takes place 285 theft of motor vehicles with four wheels the highest theft rates yet again at the West Jakarta as much as 51 cases.

This type of car that many stolen:
-Toyota Avanza
-Toyota Kijang
-Toyota Yaris
-Daihatsu Xenia
-Suzuki APV

Modus Operandi:
-Crime Rental
-Stealing in housing complex
-Intercept the victims on the road

View the original article here

Peliculas Online

5 Zone Alarm System

Each zone uses a normally closed contact. These can be micro switches or standard alarm contacts (usually reed switches). Zone 1 is a timed zone which must be used as the entry and exit point of the building. Zones 2 - 5 are immediate zones, which will trigger the alarm with no delay. Some RF immunity is provided for long wiring runs by the input capacitors, C1-C5. C7 and R14 also form a transient suppresser. The key switch acts as the Set/Unset and Reset switch. For good security this should be the metal type with a key. At switch on, C6 will charge via R11, this acts as the exit delay and is set to around 30 seconds. This can be altered by varying either C6 or R11. Once the timing period has elapsed, LED6 will light, meaning the system is armed. LED6 may be mounted externally (at the bell box for example) and provides visual indication that the system has set. Once set any contact that opens will trigger the alarm, including Zone 1. To prevent triggering the alarm on entry to the building, the concealed re-entry switch must be operated. This will discharge C6 and start the entry timer. The re-entry switch could be a concealed reed switch, located anywhere in a door frame, but invisible to the eye. The panic switch, when pressed, will trigger the alarm when set. Relay contacts RLA1 provide the latch, RLA2 operate the siren or buzzer.

Miniature Loop Alarm

A few months ago, I decided to build a compact, yet effective alarm. My demands were:- simple construction, reliable operation, very small power consumption, and, most of all, small size. I started with CMOS logic gates, but was soon forced to abandon the concept after a few unsuccessful (and far too complicated) attempts. Then I suddenly realized that a simple transistor switch might do the job and I was right.

As you can clearly see from the schematics, the circuit is utterly primitive and consists of two identical transistor switches. Each has its own alarm LED and they're coupled to a neat 82dB buzzer. The two 1N4148 diodes are used to prevent a signal from one sensor from triggering both LEDs. The sensors used are either wire loops or normally closed reed switches or even a combination of both. You could, for example, tie a wire loop to your suitcase and place a reed switch to the door of your hotel room.

Since this little alarm is intended to be kept in arms reach at all times, there aren't any provisions for automatic shutdown after a certain period of time. The buzzer will sound until you turn the whole circuit off or connect the wire loop back to the jumpers. The same goes for the two LEDs, each indicating its own zone.

Construction is not critical and there aren't any traps for the novice. The two 100n capacitors aren't really necessary, I just included them to make sure that there is no noise interference coming from the long wire loops. For transistors, you can use any NPN general-purpose audio amplifiers/switches (BC 107/108/109, BC 237/238, 2N2222, 2N3904...). Assemble the circuit on perf board. Together with the buzzer and a 9V battery, it should easily fit in a pocket-sized plastic box smaller than a pack of cigarettes. A fresh battery should suffice for weeks of continuous operation.

Modular Burglar Alarm

This circuit features automatic Exit and Entry delays and a timed Bell Cut-off. It has provision for both normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone. It is connected permanently to the 12-volt supply and its operation is "enabled" by opening SW1. By using the expansion modules, you can add as many zones as you require; some or all of which may be the inertia (shock) sensor type. All the green LEDs should be lighting before you open SW1. You then have up to about a minute to leave the building. As you do so, the Buzzer will sound. It should stop sounding when you shut the door behind you. This indicates that the Exit/Entry loop has been successfully restored within the time allowed. When you re-enter the building you have up to about a minute to move SW1 to the off position. If SW1 is not switched off in time, the relay will energise and sound the main bell. It will ring for up to about 40 minutes. But it can be turned off at any time by SW1. The "Instant" zone has no Entry Delay. If you don't want to use N/O switches, leave out R8, C8 and Q2; and fit a link between Led 3 and C7. The 24 Hour PA/Tamper protection is provided by the SCR/Thyristor. If any of the switches in the N/C loop is opened, R11 will trigger the SCR and the bell will ring. In this case the bell has no time limit. Once the loop is closed again, the SCR may be reset by pressing SW2 and temporarily interrupting the current flow. The basic circuit will be satisfactory in many situations. However, it's much easier to find a fault when the alarm is divided into zones and the control panel can remember which zone has caused the activation. The expansion modules are designed to do this. Although they will work with the existing instant zone, they are intended to replace it. When a zone is activated, its red LED will light and remain lit until the reset button is pressed. All the modules can share a single reset button. The Stripboard layout of the prototype is available.

Water Activated Alarm

The circuit uses a 555 timer wired as an astable oscillator and powered by the emitter current of the BC109C. Under dry conditions, the transistor will have no bias current and be fully off. However as the probes get wet the transistor will conduct and sounding the alarm.

An On/Off switch is provided and remember to use a non-reactive metal for the probe contacts. Gold or silver plated contacts from an old relay may be used, however a cheap alternative is to wire alternate copper strips from a piece of veroboard. These will eventually oxidize over but as very little current is flowing in the base circuit, the higher impedance caused by oxidization is not important. No base resistor is necessary as the transistor is in emitter follower, current limit being the impedance at the emitter (the oscillator circuit).

Battery Powered Burglar Alarm

Description:

This is a single zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off timers. It will accommodate the usual types of normally-closed input devices - such as magnetic-reed contacts, foil tape and PIRs.

When the alarm is activated - the Siren will sound for up to 20-minutes. Then it will switch off - and remain off. The alarm will not re-activate.

If you wish - you can use a mains power supply. But the extremely low standby current makes battery power a realistic option. I've used a 9-volt supply in the drawing - but the circuit will work at anything from 5 to 15-volts. All you need do is select a Siren, Buzzer, and Relay to suit the voltage you're using.

Schematic Diagram:

Notes:

The alarm is easy to operate. Sw1 can be any type of two-way switch. If the Buzzer sounds when you switch the alarm on - the normally-closed loop is open. Switch off again - and check the building for open doors or windows. If the Buzzer does not sound - the loop is intact.

Depending on the setting of R3 - you have up to about a minute to leave the building. As you do so - the Buzzer will sound. When you close the door behind you - it should stop sounding. This confirms that the loop has been restored within the time allowed.

When you return and open the door - the Buzzer will sound. Depending on the setting of R4 - you have up to about a minute to switch the alarm off. If you fail to do so - the Siren will sound.

Depending on the setting of R5 - the Siren will sound for up to about 20-minutes. Then it will switch off - and remain off. Of course - you can stop the noise at any time by moving Sw1 to the "off" position.

For this type of device - really precise times are not necessary. If you like - you can replace the pots with fixed resistors. For example - 2M2 resistors should give you exit and entry delays of about 30-seconds - and a Siren cut-off time of about 10-minutes.

After the cut-off timer has switched the Siren off - the Buzzer will continue to sound. So when you return - if the Buzzer is sounding - you'll know that the alarm has been activated.

The Support Material for this alarm includes a photograph of the prototype - a parts list - a detailed circuit description - a step-by-step guide to construction - and more.

Veroboard Layout:

Cmos 4060 Burglar Alarm

Description:
This is a single zone alarm - with automatic exit, entry and siren cut-off timers. It will accommodate all the usual types of normally-closed input devices - such as magnetic-reed contacts - foil tape - PIRs etc.

When the alarm is activated - the siren will sound for a fixed length of time. Then it will switch off - and remain off. The alarm will not re-activate.

I've used a 12-volt supply in the drawing - but the circuit will work at anything from 5 to 15-volts. All you need do is select a siren, buzzer, and relay to suit the voltage you're using.

Schematic Diagram:

Notes:

When you switch the alarm on - the buzzer will sound eight times. This is the exit delay. Before the end of the eighth beep - you can leave the building without activating the alarm.

R6 controls the length and speed of the beeps. It can be adjusted to give an exit delay of anything from about ten seconds - up to about a minute. After the eighth beep - the buzzer should stop sounding. This confirms that the loop has been restored within the time allowed.

If the buzzer does not stop - but changes instead to a continuous beep - the loop is open and the building isn't secure. When this happens - you should switch off the alarm - and check for open doors, windows etc.

When you return and open the door - the buzzer will sound again - and the entry delay will start. The entry delay is the same length as the exit delay. But to distinguish it from the exit delay - the buzzer will sound continuously.

If the buzzer is sounding continuously - the alarm has been activated - and the entry delay has begun. If you don't switch the alarm off before the entry delay expires - the siren will sound.

The siren will sound only once. Just as R6 sets the lengths of the exit and entry delays - it also sets the siren cut-off time. The siren cut-off delay is 30 times the length of the exit delay. With the exit delay set at 30-seconds - the siren will sound for about 15-minutes. Then it will switch off - and remain off.

Of course - you can stop the noise at any time by switching off the alarm.

After the cut-off timer has switched the siren off - the buzzer will continue to sound. So when you return - if the buzzer is sounding - you'll know that the alarm has been activated.

Note that D10 is optional. Its job is to sound the buzzer constantly during the entry delay. It's also responsible for keeping the buzzer going after the siren has stopped.

If you leave out D10 - the buzzer will beep eight times during both the exit and entry delays. And - when the siren cuts-off - the buzzer will cut off also.

Alternative Capacitor:

A regular electrolytic capacitor is polarised. If the charge on its plates is the wrong way round - DC current will flow through the capacitor. If the current is high enough - the capacitor will heat up and explode. The presence of R5 in the circuit means that this is not going to happen. But if you use a polarised capacitor - it may mean that the oscillator won't run - or won't run reliably.

While the oscillator is running - the polarity of the charge on C4 keeps reversing. So C4 needs to be non-polarised. However - you can simulate a non-polarised 10uF capacitor by connecting two 22uF polarised capacitors back to back - as shown.

How and why this works is explained in the Support Material - which also includes a photograph of the prototype - a detailed circuit description - a parts list - a step-by-step guide to construction - and more.

Because non-polarised capacitors aren't widely available - the prototype was built using two polarised capacitors.

Veroboard Layout:



To add a normally open loop contact

Power Failure Alarm

Description

This is a very basic alarm designed to let you know when the electricity supply fails. The alarm is powered from a battery which uses no current consumption at all in standby, a battery should therefore last its full shelf life.

Notes

In use, as long as the electric supply is healthy, relay RLY1 remains energized. Under this (standby) condition, the relay contacts are open and the buzzer will not sound. The battery drain is zero and should last its full shelf life of 2 years or more.

Should the power fail, the relay de-energizes, its contacts close and the alarm is sounded. BZ1 is the audible device and can be a loud piezo type sounder,bell or buzzer. The battery should be chosen to match the sounders operating voltage.
Although drawn with a full power supply; (transformer, bridge rectifier and smoothing capacitor) this can be substituted with a readily available DC adapter. In this case just chose a relay whose operating voltage matches the adapter.
Once power fails, there is no way to stop the sounder, this is why switch S1 is in circuit, to mute the alarm.

3 Zone Duress Alarm

Description

This is a 3 zone alarm for use in high risk areas or possible duress situations. Typical examples being banking or betting booths. The alarm consists of 3 normally open push button switches which can be hidden or in plain view. Once pressed the alarm will latch and a LED will light showing which zone has pressed the alarm.

Circuit Notes

The input trigger are switches S2, S3 and S4, zone 1, zone 2 and zone 3 respectively. These are push to make normally open press switches and can be concealed under a desk for example or in plain view. The input switches will be located in the remote location. S1 is the reset switch and is located on the control unit. D1 is the alarm LED for zone 1, D2 the LED for zone 2 and D3 the LED for zone 3.

The alarm itself uses two CMOS 4011 IC's. Each IC contains quad 2 input NAND gates. These gates are wired as SR flip flops, two gates per zone. U1 uses all four gates and IC U2 uses just two gates, all unused inputs should be tied to ground. The small black numbers on the schematic refer to the IC pinout, you also need to make sure that each IC has pin 7 wired to ground and pin 14 to Vcc; (these connections are not shown for clarity).

IC Pinout for the CMOS 4011 can be viewed in the Practical section, click here.

Power is derived via an external power supply and must be 14 Volts or higher. F1 is the input fuse, the supply is regulated by U3 a 78M12 regulator. C2 helps filter regulator output. At switch on, C3 quickly charges via the parallel combination of R2, R7 and R11 providing a reset pulse. All LED's and the piezo sounder, BZ1 will be off.

If any zone is triggered, the appropriate LED will light and the sounder will continue to bleep until reset by pressing S1. Q1, Q2 and Q3 amplify the output current from the NAND gates to send about 30mA through each LED. I used 10mm LED's in the prototype but lo-current type LED's (2mA) could easily be used and transistors eliminated if desired.

D4, D5 and D6 form a 3 input OR gate allowing the operation of the piezo sounder from any input zone.

When testing the prototype an unusual fault occurred. Pressing S2 or S3 would active the sounder and both D1 and D2. My immediate thought was some type of cable contact, however testing with a multimeter revealed no partial shortcircuits whatsoever. Cabling was about 20 metres total, so I wondered if cable capacitance was a factor. Small 100n filter capacitors were tried across the SR gates input, but to no avail. Eventually I found the cure and that was to include R15 a 220 ohm resistor into the supply line. CMOS can drive you crazy! It was either charge storage on the cabling of perhaps just the fact that I had used CMOS; however the inclusion of a 220 ohm resistor cured all this and allows proper operation. Below is a picture of my prototype.

Two-Zone Intruder Alarm

Description:
This is a two-zone alarm - with automatic exit, entry and siren cut-off timers. It can be triggered by the usual types of normally-closed input devices - such as magnetic reed contacts - foil tape - PIRs etc. I've used a 12-volt supply in the diagram - but the circuit will work at anything from 9 to 15-volts. All you need do is select a siren, buzzer and relay to suit the voltage you want to use.

Notes:
When you move Sw1 to the Set position - you have about 30 seconds to leave the building. If you re-enter through the Exit/Entry zone - the buzzer will sound - and you'll have about 30 seconds to switch the alarm off. The Instant zone has no entry delay. Anyone entering through the Instant zone - will sound the siren immediately.

About ten minutes after the normally-closed loops have been restored - the siren will switch off - and the alarm will return to standby mode. It can then be re-activated by a subsequent intruder. If you don't want the siren to sound a second time - add the One-Time-Only Module. It forces the siren to switch off after the first ten minutes. And it prevents the alarm from activating a second time. This module has other uses - so it's worth a look.

Veroboard Layout:

6 Zone Alarm

Description
This alarm system has 6 independent zones, 1 timed entry/exit zone, a 7 segment LED display and a test or walkthrough facility. Suitable for a small office or home environment, it can also be adapted to use a combination lock or keypad to set and reset the alarm.

Please Note: All orange +V terminals connect to the point marked +5V at the side of the set switch, S1. IC's U1,U2,U3,U4,U5 and U7 are drawn without power connections for clarity. The power connections need to go +5V and ground. See Practical Section for IC pinouts and relay contacts.

Circuit Notes:
All zones Z1 to Z6 use normally closed alarm contacts. Zone 1 is a timed zone which must be used as the entry and exit point of the building. Zones 2 to 6 are immediate zones, which will trigger the alarm with no delay. Some RF immunity is provided for long wiring runs by the input capacitors, C1 - C6. The key switch, S1 acts as the Set and Reset/Unset switch. For best security this should be the metal type switch with a key. All IC's except IC6 are CMOS types with buffered outputs, these are denoted by the suffix "B". Unbuffered CMOS IC's have a suffix starting "U" and will not work in this circuit. IC6 is a 5 Volt regulator providing power to the main CMOS IC's, the alarm power supply can be any suitable 12 to 15V power supply.
In operation the DPDT switch S2 is set to the "run" position. When keyswitch S1 is turned reset, this is the unset (off) state of the alarm. In this condition capacitor C8 will discharge via D9, R1 and Z1 and capacitor C7 will have discharged via D8, R17 and S1. Relay RLY1 will not be energized and all CMOS IC's and the display will have no power.
When S1 is turned to set all CMOS IC's receive 5 Volt power. C11 will briefly charge and apply a low input signal to one half of U7A a CMOS4001B, a dual input OR gate. The output of U5A will also be low (make sure all windows and doors zones 2 to 5 are shut) and the output of U7A is high. The output of U7A is then inverted by U7B and fed back via R18 to U7A's input keeping the circuit latched. The output of U7B is low and so Q1 and the relay RLY1 is off and no alarm will sound.
Also when S1 is set, C8 slowly charges via R13. C8 and R13 form the exit timer and allow time to vacate the building. The delay is approximately 1.1 x the value of C8 (in uF) or about 52 seconds with values shown. During the exit delay zone switch Z1 can be opened and closed without triggering the alarm. After the exit time ends, C8 will be charged and one half of the 2 input AND gate, U4A will now be high. Any opening of zones 2 through 6 will cause the alarm to trigger and relay RLY1 will energize. If an intruder attempts a break-in via zone 4 for example, the output of U1D will change state from low to high. When this happens, the high signal is forwarded by U2C a triple input OR gate CMOS4075 and is sent to input C on the CMOS4511 BCD to Decimal display driver. The binary code for four is 100 and input C is high, A abd B are low, and the LED display will illuminate digit 4. The high output from U2C is also forwarded to U5A, again a triple input OR gate. The output of U5A is now sent via S2 to the input of U7A. U7A and U7B form a bistable latch, the change in state causing the output of U7A to change to low, the output of U7B to become high and fed back via R18 to the input of U7A again. The circuit is now latched in the high state. The high output of U7B does two things. First it switches on Q1 and relay RLY1 sounding the alarm. Secondly the high output at U7B is applied to the blanking input of the CMOS4511B via S2 and also to the enable latching pin. The display will now continually show the number of the triggered zone, even if the zone switch is opened or closed again. It is a similar process for any of the other immediate zones.
As this alarm uses 6 zones, the CMOS 4511 BCD to decimal decoder must count to 6 which is 110 in binary. Therefore only inputs A,B and C are required, D is simply tied to ground. The pinout for the CMOS 4511 is shown below.

CMOS 4511

If the building is entered via Zone 1 then the entry timer starts. The output of U1A (in the set condition ) is low. Entry via Z1 triggers U1A to become momentarily high as the door is opened. U4A then produces a high output, as does U4B. The high signal is now passed via D7 to the input of U1A latching it in the high state. C7 then charges via R15. This is the entry delay and is approximately 1.1 x 0.47 x C7 or about 24 seconds with values shown. Once charged U4C will become high, trigger the alarm and cause the LED display to be latched, as per the preceding paragraph.
Switch S2 is normally used in the run position. However in the test position, this allows a useful "walkthrough" test of the alarm. In the test position the input of U7A is always low and will not trigger the alarm, also the blanking input is also high, meaning that the 7 segment display is always illuminated. With all zones closed, open any zone, the corresponding number will be shown on the display. Note that if two zones are opened the diplay will not necessarily indicate the correct zone, this is not a fault, just the way the circuit is designed. When in run mode, the first zone to trigger the alarm is "caught" and latched and will be displayed until the alarm is reset.


Features:
This alarm has a 7 segment LED display to indicate which zone triggered the alarm.
Each zone Z1 to 6 has its own indicator.
Switch S1 is a single pole, double throw switch. One position is set, the other is reset/unset.
Switch S2 enables a "walkthrough" test to test all zones and the display.
Zone 1 has independent exit and entry times.

Operation:
Turn S2 to run. The alarm is now set using S1, exit delay is determined by C8 and R13. Any entry via zones Z2 to Z6 will now immediately trigger the alarm. If alarm is triggered, reset using S1. Entering via Z1 starts the entry delay. Switch S1 to reset before the entry timer expires. If S2 is in test mode, then a walkthrough test of zones can be made.

Expansion:
R13 and R15 may be changed for preset resistors to create variable entry and exit delays. Using a 2M2 preset will allow larger entry and exit delays when set to maximum resistance. To use with a keypad e.g. Ron J's 5 digit enhanced keypad use a DPDT relay in the keypad. The unused DPDT relay contact will replace the switch S1 in this alarm circuit, see diagram below.

Parts List:

Designation   Value   Quantity
 BZ1    12V Buzzer or Siren 1
 C1,C2,C3,C4,C5,C6,C9,C11 100n   8
 C7,C8    47u   2
 C10    100u   1
 LED1 to LED6   Red LED   6
 D7,D8,D9   1N4148   3
 DISP1    7 segment CC  1
 Q1    2N3904   1
 R1,R4,R6,R7,R10,R11  100k   6
 R2,R3,R5,R8,R9,R12  270R   6
 R13    1M   1
 R14    4k7   1
 R15,R18    470k   2
 R16    100R   1
 R17    1K   1
 R19    10K   1
 RLY1           12V Relay Coil 500R  1
 Z1,Z2,Z3,Z4,Z5,Z6  NC Contacts  6 
 S1    SPDT   1 
 S2    DPDT   1
 U1    4050B   1
 U2,U5    4075B   2
 U3    4511B   1
 U4    4081B   1
 U6    7805   1
 U7    4001B   1

Hijack Alarm No. 3

Description:
Like the first two Hijack Alarms - this circuit was designed primarily for the situation where a hijacker forces the driver from the vehicle. If a door is opened while the ignition is switched on - the circuit will trip. After a few minutes delay - when the thief is at a safe distance - the Siren will sound.

Where it differs from the first two alarms - is in what happens next. I'm obliged to Victor Montanez from the USA who suggested that the engine cut-out should not operate - until the vehicle comes to a stop. That way - the engine will not fail suddenly or unexpectedly. And the hijacker will retain control.

I haven't been able to implement Victor's excellent suggestion completely - because I couldn't think of a simple, reliable and universally applicable way of sensing when the vehicle has come to a stop.

Instead - I have postponed engine failure until the ignition is switched off. Once the thief turns off the ignition - the engine will not re-start. Clearly - there is no certainty as to when this will occur. But I think it will occur sooner rather than later. Because there's a strong possibility that the hijacker will turn off the ignition - in an attempt to silence the siren.

As well as acting as a Hijack Alarm - this circuit offers some added protection. Like the Enhanced Hijack Alarm - it incorporates Jeff Chia's suggestion. That is - every time the ignition is switched on - the alarm will trip. So it will protect the vehicle whenever you leave it unattended with the ignition switched off - even overnight in your driveway. Before fitting this or any other engine cut-out to your vehicle - carefully consider both the safety implications of its possible failure - and the legal consequences of installing a device that could cause an accident. If you decide to proceed - you will need to use the highest standards of materials and workmanship.

Notes:
You're going to trip this alarm unintentionally. When you do - the LED will light and the Buzzer will give a short beep. The length of the beep is determined by C4. Its purpose is to alert you to the need to push the reset button. When you push the button - the LED will switch-off. Its purpose is to reassure you that the alarm has in fact reset.

If the reset button is not pressed then - about 3 minutes later - both the Siren and the Buzzer will sound continuously. The length of the delay is set by R8 & C5. For extra effect - fit a second siren inside the vehicle. With enough noise going on - you may feel that it's unnecessary to fit the engine cut-out. In which case - you can leave out C7, D8, R12, R13, Ty1 & Ry2.

When the ignition is switched on - C3 & R4 are responsible for tripping the alarm. By taking pin 1 low momentarily - they simulate the opening of a door. If you don't want the alarm to trip every time you turn on the ignition - simply leave out C3 & R4.

Because the voltage on C3 may be reversed - the capacitor needs to be non-polarized. But connecting two regular 22uF capacitors back to back as shown - will work just as well. Because non-polarized capacitors are not widely available - the prototype was built using two polarized capacitors.

To reset the circuit you must - EITHER turn off the ignition - OR close all of the doors - before you press the reset button. While BOTH the ignition is on - AND a door remains open - the circuit will NOT reset.

The reset button carries virtually no current - so any small normally-open switch will do. Eric Vandel from Canada suggests using a reed-switch hidden behind (say) the dash - and operated by a magnet. I think this is an excellent idea. As Eric said in his email: - "... that should keep any thief guessing for a while."

The Flow Chart is another of Eric's suggestions. It will help you to visualize how the alarm is operated. It also explains the sequence of events that lead to siren activation - and the engine's subsequent failure to re-start.

Veroboard Layout:

How you prevent the engine from starting is up to you. It should happen when Ry2 de-energizes. The contacts of Ry2 are too small to do the job themselves. So use them to switch the coil of a larger relay. Remember that the relay must be suitable for the current it's required to carry. Choose one specifically designed for automobiles - it will be protected against the elements - and will give the best long-term reliability. You don't want it to let you down on a cold wet night - or worse still - in fast moving traffic!!! Remember also that you must fit a 1N4001 diode across YOUR relay's coil - to prevent damage to the Cmos IC.

YOUR relay should drop-out when Ry2 de-energizes. Wire YOUR relay so that when it drops-out the engine will not start. Because turning-off the ignition will cause both Ry2 and YOUR relay to de-energize - the standby current will be low - and the engine will be disabled while the vehicle is parked.

The circuit board must be protected from the elements. Dampness or condensation will cause malfunction. Fit a 1-amp in-line fuse AS CLOSE AS POSSIBLE to your power source. This is VERY IMPORTANT. The fuse is there to protect the wiring - not the components on the circuit board. Please note that I am UNABLE to help any further with either the choice of a suitable relay - or with advice on installation.

Both the Siren and the Buzzer will go on sounding until the alarm is reset. The circuit is designed to use an electronic Siren drawing up to about 500mA. It's not usually a good idea to use the vehicle's own Horn because it can be easily located and disconnected. However, if you choose to use the Horn, remember that Ry1 is too small to carry the necessary current. Connect the coil of a suitably rated relay to the "Siren" output. This can then be used to sound the Horn.

Hijack Alarm

Description:

The first circuit was designed for the situation where a hijacker forces the driver from the vehicle. If a door is opened while the ignition is switched on - the circuit will trip. After a few minutes delay - when the thief is at a safe distance - the alarm will sound and the engine will fail.

Before fitting this or any other engine cut-out to your vehicle - carefully consider both the safety implications of its possible failure - and the legal consequences of installing a device that could cause an accident. If you decide to proceed - you will need to use the highest standards of materials and workmanship.

Notes:
You're going to trip this alarm unintentionally. When you do - the LED will light and the Buzzer will give a short beep. The length of the beep is determined by C3. Its purpose is to alert you to the need to push the reset button. When you push the button - the LED will switch-off. Its purpose is to reassure you that the alarm has in fact reset.

If the reset button is not pressed then - about 3 minutes later - both the Siren and the Buzzer will sound continuously. The length of the delay is set by R7 & C4. For extra effect - fit a second siren inside the vehicle. With enough noise going on - you may feel that it's unnecessary to fit the engine cut-out. In which case - you can leave out D8, D9, R11, R12, R13, C6, Q3, Q4 & Ry2.

Even if you missed the early warning provided by the Buzzer - there is still time to reset the alarm before Ry2 de-energizes - and the engine fails. This additional delay - currently about 1 minute - is set by C6 and R13.

To reset the circuit you must - EITHER turn off the ignition - OR close all of the doors - before you press the reset button. While BOTH the ignition is on - AND a door remains open - the circuit will NOT reset.

The reset button carries virtually no current - so any small normally-open switch will do. Eric Vandel from Canada suggests using a reed-switch hidden behind (say) the dash - and operated by a magnet. I think this is an excellent idea. As Eric said in his email: - "... that should keep any thief guessing for a while."

The Flow Chart is another of Eric's suggestions. It will help you to visualize how the alarm is operated. It also explains the sequence of events that lead to siren activation - and subsequent engine failure.

Veroboard Layout:

How you bring your vehicle to a standstill is up to you. It should happen when Ry2 de-energizes. The contacts of Ry2 are too small to do the job themselves. So use them to switch the coil of a larger relay. Remember that the relay must be suitable for the current it's required to carry. Choose one specifically designed for automobiles - it will be protected against the elements - and will give the best long-term reliability. You don't want it to let you down on a cold wet night - or worse still - in fast moving traffic!!! Remember also that you must fit a 1N4001 diode across YOUR relay's coil - to prevent damage to the Cmos IC.

YOUR relay should drop-out when Ry2 de-energizes. Wire YOUR relay so that when it drops-out the engine will stop. Because turning-off the ignition will cause both Ry2 and YOUR relay to de-energize - the standby current will be low - and the engine will be disabled while the vehicle is parked.

The circuit board must be protected from the elements. Dampness or condensation will cause malfunction. Fit a 1-amp in-line fuse AS CLOSE AS POSSIBLE to your power source. This is VERY IMPORTANT. The fuse is there to protect the wiring - not the components on the circuit board. Please note that I am UNABLE to help any further with either the choice of a suitable relay - or with advice on installation.

Both the Siren and the Buzzer will go on sounding until the alarm is reset. The circuit is designed to use an electronic Siren drawing up to about 500mA. It's not usually a good idea to use the vehicle's own Horn because it can be easily located and disconnected. However, if you choose to use the Horn, remember that Ry1 is too small to carry the necessary current. Connect the coil of a suitably rated relay to the "Siren" output. This can then be used to sound the Horn.

The Support Material for the First Hijack Alarm includes a parts list - a step-by-step guide to construction - a detailed circuit description - and more.

Enhanced HiJack Alarm

The second alarm is a variation on the first. My original idea was to have the circuit sit quietly in the background - and only require the driver to intervene if the alarm were tripped accidentally. However, I'm obliged to Jeff Chia from Canada who suggested the following enhancement.

By making the alarm trip automatically the moment the ignition is switched on - it will protect the vehicle in many more situations. For example at the Service Station - while you're filling the tank - checking the tyre pressure - paying at the cash desk etc. In fact it works whenever you leave the vehicle unattended with its ignition switched off - even overnight in your driveway.

Jeff's suggestion has made me reconsider the value of the initial design approach - and I think that having to press the reset button every time you turn on the ignition - is a small price to pay for the added protection.

If you've already built the original version - and want to add the modification - remove the 12-volt input terminals. That should provide enough space for the additional components.

The Flow Chart for the Enhanced Alarm will help you to visualize how it's operated. It also explains the sequence of events that lead to siren activation - and subsequent engine failure.

audio Security Monitor

Description:
A remote listening circuit. The area to be monitored is connected via a cable and allows remote audio listening.

Notes:
You can use this in your garden and listen for any unusual sounds, or maybe just wildlife noises. If you have a car parked in a remote location, the microphone will also pick up any sounds od activity in this area. The cable may be visible or hidden, screened cable is not necessary and you can use bellwire or speaker cable if desired.

Circuit Description:
Starting from the right hand side, the power supply. I have used 12V as a standard power supply voltage, or a 12V car battery may be used. The circuit is in two halves, a remote microphone preamp, and an audio amplifier based around the National Semiconductor LM386 audio amplifier.

The remote preamp uses an ECM microphone to monitor sound. A direct coupled 2 stage amplifier built around Q1 and Q2 amplify the weak microphone signal. Preset resistor R2 acts as a gain control, and C1 provides some high frequency roll off to the overall audio response. Q1 is run at a low collector current for a high signal to noise ratio, whilst Q2 collector is biased to around half the supply voltage for maximum dynamic range. The power supply for this preamp is fed via R10 and R6 from the 12V supply. C4 ensures that the preamp power supply is decoupled and no ac voltages are present on the power lines. The amplified audio output from Q2 collector is fed onto the supply lines via C6 a 220u capacitor. The output impedance of Q2 is low, hence the relatively high value of C6. C6 also has a second purpose of letting the output audio signals pass, whilst blocking the dc voltage of the power supply.

At the opposite end, C7 a 10u capacitor, brings home the amplified audio to the listening location. The signal is first further amplifier by a x10 voltage gain amplified using the TL071. C8, a 22p capacitor again rolls off some high frequency response above 100kHz. This is necessary as long wires may pick up a little radio interference. After amplification by the op-amp, the audio is finally passed to the LM386 audio amplifier. R14 acts as volume control. R13 and C12 prevent possible instability in the LM386 and are recommended by the manufacturer. Audio output is around 1 watt into an 8 ohm loudspeaker, distortion about 0.2%. If preferred headphones could be used, although I'd recommend a series resistor of the same value impedance as the headphones.

One Time Only Alarm

Description:

This alarm is designed to sound its Siren only once. That is - when the alarm is activated - the Siren will sound for a preset length of time. Then it will switch off and remain off. The alarm will not re-activate.

The basic circuit has a single zone with independently adjustable Exit and Entry delays. The zone will accommodate the usual types of normally-open and normally-closed input devices - such as pressure mats, magnetic-reed contacts, micro switches, foil tape and PIRs.

A range of Expansion Modules allow you to add any number of Instant Alarm Zones, Personal Attack Zones and Tamper Zones to your system. There's also an Untimed Output Module. It will keep an internal sounder, strobe-light, lamp or whatever going after the siren has stopped.

Schematic Diagram:

Notes:
The alarm may be operated by a simple hidden two-way switch - such as a light switch. If you want more security - you can use a key switch - or one of a number of code operated Keypad Switches.

Before you set the alarm - make sure that the building is secure - that ALL of the Green LEDs are lighting - and that the Yellow LED is off. If the Yellow LED is lighting - there's a fault in one of the zones - and THE ALARM WILL NOT SET.

Depending on the setting of R9 - when you move Sw1 to the "set" position - you have up to about a minute to leave the building. When you return and open the door - the Buzzer will sound. Depending on the setting of R8 - you have up to about a minute to switch the alarm off. If you fail to do so - the Siren will sound.

Depending on the setting of R14 - the Siren will sound for up to about 20-minutes. Then it will switch off - and remain off. Of course - you can stop the noise at any time by moving Sw1 to the "off" position.

When you return - if the Buzzer does not sound and the Yellow LED is lighting - then there's been an activation while you were away.

The Support Material for this alarm includes a detailed circuit description - a parts list - a step-by-step guide to construction - and more.

Veroboard Layout:

Multi-Zone Transistor Alarm

Description:

This is a simple transistor-based burglar alarm circuit. Its features include automatic Exit and Entry delays - together with a timed Bell cut-off and Reset. It's designed to be used with the usual types of normally-closed input devices such as - magnetic-reed contacts - micro switches - foil tape - and PIRs.

The basic alarm has an "Exit/Entry" zone and an "Instant" zone. This will be adequate in many situations. However - larger buildings are best divided into a number of smaller zones. The design allows you to Add As Many Zones As You Like to the basic system. They are "Instant Zones" - and may be triggered by both normally-open and normally-closed input devices.

Schematic Diagram:

Notes:

It's easy to use. Make sure that the green LED is lighting - then switch the alarm on using Sw1. You have about 30 seconds to leave the building. When you return and open the door - the Buzzer will sound. You have about 30 seconds to switch off the alarm. If you fail to do so - the Siren will sound.

While at least one of the trigger switches remains open - the Siren will continue to sound. However - if the trigger circuits have been restored - the alarm will reset itself after about 10 minutes. Of course - you can turn the Siren off at any time by switching off the alarm.

Because of manufacturing tolerances - the precise length of any delay depends on the characteristics of the actual components you've used in your circuit. But - to some degree - by altering the values of R2, R7 & R9 you can adjust the Exit, Entry and Reset times to suit your requirements. Increasing the values increases the time - and vice-versa.

If you don't want the "Instant" zone - leave out D7, D8, D9, R12, R13, C8 and the Green LED.

The Support Material for this alarm includes a detailed circuit description - a parts list - a step-by-step guide to construction - and more.

Veroboard Layout:

Battery Powered Burglar Alarm

Description:

This is a single zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off timers. It will accommodate the usual types of normally-closed input devices - such as magnetic-reed contacts, foil tape and PIRs.

When the alarm is activated - the Siren will sound for up to 20-minutes. Then it will switch off - and remain off. The alarm will not re-activate.

If you wish - you can use a mains power supply. But the extremely low standby current makes battery power a realistic option. I've used a 9-volt supply in the drawing - but the circuit will work at anything from 5 to 15-volts. All you need do is select a Siren, Buzzer, and Relay to suit the voltage you're using.

Schematic Diagram:

Notes:

The alarm is easy to operate. Sw1 can be any type of two-way switch. If the Buzzer sounds when you switch the alarm on - the normally-closed loop is open. Switch off again - and check the building for open doors or windows. If the Buzzer does not sound - the loop is intact.

Depending on the setting of R3 - you have up to about a minute to leave the building. As you do so - the Buzzer will sound. When you close the door behind you - it should stop sounding. This confirms that the loop has been restored within the time allowed.

When you return and open the door - the Buzzer will sound. Depending on the setting of R4 - you have up to about a minute to switch the alarm off. If you fail to do so - the Siren will sound.

Depending on the setting of R5 - the Siren will sound for up to about 20-minutes. Then it will switch off - and remain off. Of course - you can stop the noise at any time by moving Sw1 to the "off" position.

For this type of device - really precise times are not necessary. If you like - you can replace the pots with fixed resistors. For example - 2M2 resistors should give you exit and entry delays of about 30-seconds - and a Siren cut-off time of about 10-minutes.

After the cut-off timer has switched the Siren off - the Buzzer will continue to sound. So when you return - if the Buzzer is sounding - you'll know that the alarm has been activated.

The Support Material for this alarm includes a photograph of the prototype - a parts list - a detailed circuit description - a step-by-step guide to construction - and more.

Veroboard Layout:

4 Digit Alarm Keypad

Description

This is an enhanced 4 digit keypad which may be used with the Modular Alarm System.

Notes

The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 terminals will NOT do. The Alarm is set by pressing a single key. Choose the key you want to use and wire it to 'E'. Choose the four keys you want to use to switch the alarm off, and connect them to 'A B C & D'. Your code can include the non-numeric symbols. With a 12-key pad, over 10 000 different codes are available. Wire the common to R1 and all the remaining keys to 'F'. When 'E' is pressed, current through D2 and R9 switches Q5 on. The relay energises, and then holds itself on by providing base current for Q5 through R10. The 12-volt output is switched from the "off " to the "set " terminal, and the LED lights. To switch the Alarm off again it is necessary to press A, B, C & D in the right order. The IC is a quad 2-input AND gate, a Cmos 4081. These gates only produce a high output when both inputs are high. Pin 1 is held high by R5. This 'enables' gate 1, so that when 'A' is pressed, the output at pin 3 will go high. This output does two jobs. It locks itself high using R2 and it enables gate 2 by taking pin 5 high. The remaining gates operate in the same way, each locking itself on through a resistor and enabling its successor. If the correct code is entered, pin 10 will switch Q4 on and so connect the base of Q5 to ground. This causes Q5 to switch off and the relay to drop out. Any keys not wired to 'A B C D or E' are connected to the base of Q3 by R7. Whenever one of these 'wrong' keys is pressed, Q3 takes pin 1 low. This removes the 'enable' from gate 1, and the code entry process fails. If 'C' or 'D' is pressed out of sequence, Q1 or Q2 will also take pin 1 low, with the same result. You can change the code by altering the keypad connections. If you need a more secure code use a bigger keypad with more 'wrong' keys wired to 'F'. A 16-key pad gives over 40 000 different codes. All components are shown lying flat on the board; but some are actually mounted upright. The links are bare copper wires on the component side. Two of the links must be fitted before the IC.

Veroboard Layout

Radio Wave Alarm

Description:

This simple circuit is sure to have the police beating a path to your door- however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat.

Circuit Notes

The circuit transmits on Medium Wave (this is the small problem with the police). IC1a, together with a sensor (try a 20cm x 20cm sheet of tin foil) oscillates at just over 1MHz. This is modulated by an audio frequency (a continuous beep) produced by IC1b. When a hand or a foot approaches the sensor, the frequency of the transmitter (IC1a) drops appreciably.

Suppose now that the circuit transmits at 1MHz. Suppose also that your radio is tuned to a frequency just below this. The 1MHz transmission will therefore not be heard by the radio. But bring a hand or a foot near to the sensor, and the transmitter's frequency will drop, and a beep will be heard from the radio.

Attach the antenna to a multiplug adapter that is plugged into the mains, and you will find that the Medium Wave transmission radiates from every wire in your house. Now place a suitably tuned Medium Wave radio near some wires or a plug point in your house, and an early-warning system is set up.

Instead of using the sheet of tin foil as the sensor, you could use a doorknob, or burglar bars. Or you could use a pushbutton and series resistor (wired in series with the 33K resistor - the pushbutton would short it out) to decrease the frequency of IC1a, so activating the system by means of a pushbutton switch. In this case, the radio would be tuned to a frequency just below that of the transmitter.

Novel Buzzer

Circuit Notes

This novel buzzer circuit uses a relay in series with a small audio transformer and speaker. When the switch is pressed, the relay will operate via the transformer primary and closed relay contact. As soon as the relay operates the normally closed contact will open, removing power from the relay, the contacts close and the sequence repeats, all very quickly...so fast that the pulse of current causes fluctuations in the transformer primary, and hence secondary. The speakers tone is thus proportional to relay operating frequency. The capacitor C can be used to "tune" the note. The nominal value is 0.001uF, increasing capacitance lowers the buzzers tone.