ALARM PROJECTS and CIRCUITS
Gate Alarm project
An electronic project that is cheap and simple.This gate alarm is made from a single CMOS Integrated Circuit.
Water Level Alarm project
A circuit that offers visual indication of fluid level in a vessel, with a switchable audible alarm. Example uses would be to monitor the level of water in a bath or cold storage tank.
Motorcycle Alarm circuit
Any number of normally open switches may be used. Fit the mercury switches so that they close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches to protect removable panels and the lids of panniers etc. While at least one switch remains closed, the siren will sound.
5 Zone Alarm System
-This is a complete alarm system with 5 independent zones suitable for a small office or home environment. It uses just 3 CMOS IC's and features a timed entry / exit zone, 4 immediate zones and a panic button. There are indicators for each zone a "system armed" indicator.
Miniature Loop Alarm
-construction, reliable operation, very small power consumption, and, most of all, small size alarm using only transistor components.
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.
Water Activated Alarm
-This simple circuit uses a 555 timer wired as an astable oscillator and powered by the emitter current of the a transitor. Under dry conditions, the transistor will have no bias current and be fully off. As the probes get wet, a small current flows between base and emitter and the transistor switches on. A larger current flows in the collector circuit enabling the 555 oscillator to sound.
Novel Buzzer
-This novel buzzer circuit project 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.
Radio Wave Alarm
-The circuit transmits on Medium Wave Together with a sensor oscillates at just over 1MHz. This circuit is modulated by an audio frequency produced by IC.
This simple circuit is capable of alerting you when it senses someone even before their footsteps fall on the area
5 Digit Alarm Keypad
-This project is an enhanced 5 digit keypad which may be used with the Modular Alarm System
4 Digit Alarm Keypad
-This is an enhanced 4 digit keypad which may be used with the Modular Alarm System.
Single Zone Alarm
A single zone alarm circuit with entry and exit delay and other facilities.
Single Zone CMOS Alarm project
-This circuit features automatic Exit/Entry delays, timed Bell Cut-off and System Reset. It has provision for normally open and normally closed switches and will accommodate the usual input devices such as Foil Tape, Pressure Mats, Magnetic Reed Contacts, Passive Infrared Detectors and Inertia (Shock) Sensors.
Mini Alarms
-This is a selection of small self-contained alarm circuits. They have a very low standby current; and are suitable for battery operation.
Car Alarm and Immobilizer project
-This circuit features exit and entry delays, an instant alarm zone, an intermittent siren output and automatic reset. By adding external relays you can immobilize the vehicle and flash the lights.
Hijack Alarm circuit
-This 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.
Snore Alarm project
-The idea behind this snore alarm project , is just to rouse the snorer, not the entire household. To wake the sleeper, vibration is used, not an audible alert. This circuit has a level control and peak display indicator, a variable trigger threshold and trigger indication.
Motorcycle Alarm No. 2
-This circuit features an intermittent siren output and automatic reset.
An SCR Based Burglar Alarm
-This is a simple SCR 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.
Multi-Zone Transistor Alarm
-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.
One Time Only Alarm
-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.
Battery Powered Burglar Alarm
-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.
Cmos 4060 Burglar Alarm
-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.
Security Monitor
-A remote listening circuit. The area to be monitored is connected via a cable and allows remote audio listening.
Hijack Alarm No. 3
-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.
6 Zone Alarm
-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.
Frost Alarm
-this is a basic temperature controlled alarmThe thermistor used has a resistance of 15k at 25 degrees and 45k at 0 degrees celsius. A suitable bead type thermistor is found in the Maplin catalogue. The 100k pot allows this circuit to trigger over a wide range of temperatures. A slight amount of hysteresis is provided by inclusion of the 270k resistor. This prevents relay chatter when temperature is near the switching threshold of this circuit.
Fridge door Alarm
-This circuit, enclosed in a small box, is placed in the fridge near the lamp (if any) or the opening. With the door closed the interior of the fridge is in the dark, alarm will not activate
Emergency Light and Alarm
-This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen.
When power supply is restored, the lamp or the alarm is switched-off. A switch provides a "latch-up" function, in order to extend lamp or alarm operation even when power is restored.
Low Voltage Alarm
-This low voltage circuit can be used to monitor batteries and other volatile sources of current for problems. The circuit sounds an alarm and lights an LED, but can be interfaced to any number of other circuits for many different uses.
Everything-that-moves ALARM
-A crucial failing of proximity detectors is their unreliable and tricky nature. This is where they are used to detect humans, not to speak of smaller living beings. One common approach is to detect eddy currents in a living body, which are induced in the body through a.c. mains wiring. However, such circuits become altogether unusable in the case of mains failure, or in the absence of mains electricity, or even where adjacent mains circuits are switched in and out.
Temperature Switch Project
-This project will provide you an understanding of the use of germanium diode and how it works compared to the more common silicon diode. It works on the principle that as the temperature surrounding the germanium diode increases, the back resistance decreases sharply.
Simple Home Security Monitoring Project
-This project is a standalone simple home security monitoring project that will trigger a buzzer when the magnetic contact is opened. Magnetic contacts are usually NC (Normally Closed) and are used on doors and windows. They consists of two parts namely a magnet and a reed switch. When the reed switch is in close proximity to the magnet, the switch will close and vice versa. Usually the magnet is fitted to the door and the reed switch is fitted to the door frame in close proximity to one another such that when the door is closed, the two parts are in close contact and hence the switch is closed. When the door is opened, the magnet will be a distance away from the reed switch and hence the switch will open.
Door Bell Chime Project
-This door bell chime electronic project provides the schematic and the parts list needed to construct a very simple wired door bell alarm that you can place on the door of your house. It is a very low cost and affordable project that every beginners to electronic design can hands on. Constructing this project will help the beginners to electronics to understand one of the applications of 555 timer that is configured in an astable mode. This project uses a 555 timer integrated circuit, a speaker, 5 resistors, 4 electrolytic capacitors, 1 ceramic capacitor, 3 diodes, 1 pushbutton switch and 9 V battery as power supply.
Construct a 9V Siren
-This project provides the schematic and the parts list needed to construct a very simple Siren. This project will help beginners to electronics understand one of the application of operational amplifers(OP AMP). In this case, the LM 358 operational amplifier is configured as a VCO(Voltage Controlled Oscillator).
Power Failure Alarm Project
-This project is a power supply monitoring device that will trigger a buzzer when the mains supply cuts off. At the same time, the light emitting diode will be turned ON. This device is helpful to inform the loss of power supply to some critical installation such as a pump in a fish tank. Once the buzzer sound, one will know that there is a loss of power supply and actions need to be taken to rectify the situation by providing alternative power supply or relocating the installation.
Construct a 6-15V Alarm
-This project provides the schematic and the parts list needed to construct a very simple Alarm. This is a simple project and will help the beginners to electronics to understand one of the functions of 555 timers and one of their application. 556 timers has 2 of 555 timers.
Simple Home Alarm
-This simple standalone home alarm project is a good project for those who are eager to know the concept of home security system. This circuit which consists of three 555 timers gets the input from a contact that could be connected to a motion detector or any momentary contact that monitors a certain process.
Constructing your own Light Alarm
-This project provides the schematic and the parts list needed to construct a simple Light Alarm. Protect your medicine cabinet, cash drawer or lolly cupboard with this alarm. It will sound as soon as the drawer is opened and light falls on the Darlington phototransistor. The project is a light alarm which will detect very low levels of light. It will not work as well as your eye in detecting light because the human eye is the most sensitive light detector there is.
MICRO POWER OVER-TEMPERATURE ALARM
-The circuit is powered for years by a single 3 volt lithium battery. It sounds an alarm when the temperature exceeds a certain point. With some minor changes the circuit could also be configured for an under temperature (freeze) alarm project.
POWER REMINDER BEEPER
-This circuit produces a short beep once each minute. It is powered directly off the 120vac power line to remind you that a device connected to the circuit is turned on. It is simple enough to be packaged inside a small plastic box. It might be ideal for computers, printers or some test equipment that shouldn't be left on all night
DOORKNOB ALARM
-Many companies offer simple alarm devices for personal use in bedrooms or hotel rooms. A metal chain attached to a box holding the electronics is placed around the inside doorknob of a wood door. Anyone grabbing the knob from the outside is detected by the electrical capacitance change that occurs from the human hand contact between the knob and the box.
WATER SEEPAGE ALARM
-This simple circuit sounds a beeper when its electrodes detect water. It is powered by a single 1.5v N cell. A small 1.5v button battery will also work.
Wire Loop Alarm
-This circuit is a simple wire loop alarm that can be used in doorways, hallways, or any other place the tripwire will be broken by intruders.
Water Level Indicator With Alarm
-Here is a simple, versatile circuit which indicates the level of water in a tank. This circuit produces alarm when water level is below the lowest level L1 and also when water just touches the highest level L12. The circuit is designed to display 12 different levels.
Water-Level Controller
-The simple circuit presented here makes this system automatic, it switches on the pump when the water level in the overhead tank goes low and switches it off as soon as the water level reaches a pre-determined level. It also prevents ‘dry run’ of the pump in case the level in the underground tank goes below the suction level.
Ultrasonics: remote control and Intruder detector
-this circuit is an ultrasonic intruder detector. It uses Doppler shift from a moving object. Ultrasonics aren't used much for this commercially as they can be a bit temperamental to set up and tend to detect cats and curtains moving in a draft. Modern detectors tend to use a narrow beam microwave system which only scans a small area such as a doorway. Ultrasonics tend to scan the whole room.
Touch Activated Switch
- The circuit is powered from a standard +5v supply. It has both a source and sink output that change state whenever a metal button connected to the circuit is touched. An earth ground reference is required.
TINY 2-ZONE ALARM
-Since I travel a lot during summer, I decided to build a really small alarm that could easily fit inside a pocket. However, I also demanded reliable operation, simple construction and very low power consumption. I started with CMOS logic gates, but was soon forced to abandon the concept after a few unsuccessful (and far too complicated) takes.
A snore alarm electronic device
-Here I describe a little electronic device that detects snoring. The principle though very simple is efficient and well protected against false triggerings. Upon detection, it generates a noisy and painfull alarm. Just what's necessary to wake up everybody except the snorer.
Simple Alarm System
-car alarm system based on PIC 12C508 Version 1.0
Refrigerator Door Alarm
- Here's a simple circuit that beeps whenever the door is open for an extended period of time (which will also put a little pressure on the fridge loiterers in the house).
KNOCK ALARM
-This circuit used in conjunction with a thin piezoelectric plate, senses the vibration generated on
knocking a surface
Build The Universal Alarm System
-universal alarm system that can be used everywhere and is very affordable.very simple to construct and only basic electronics is needed.
Home security system
-This application of the Basic Serial Interface circuit illustrates how easy it is to develop a sophisticated home security system
Fuse Monitor Indicator
- this project is a very simple way to check if a fuse has blown without removing it from its holder.
Electronic Card-Lock System
-The circuit presented here can be used as a lock for important electronic /electrical appliances. When card is inserted inside its mechanism.
Battery Low Voltage alarm
-This circuit provides an audible and visual low voltage warning for 12V battery powered devices. When the battery voltage is above the set point (typically 11V), the circuit is idle. If the battery voltage should fall below the set point, the LED will light and the speaker will emit a periodic beeping sound to warn of the impending loss of power.
UNPLUGGED POWER CORD ALARM
-circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of time
Infra-red Level Detector project
-This circuit is useful in liquids level or proximity detection. It operates detecting the distance from the target by reflection of an infra-red beam. It can safely detect the level of a liquid in a tank without any contact with the liquid itself. The device's range can be set from a couple of cm. to about 50 cm. by means of a trimmer.
Broken Charger-connection Alert
-The above circuit can be useful to detect if the load of any battery charger or plug-in adaptor supply is not properly connected. The load can be a set of batteries to be charged or any other type of battery or low dc voltage operated device.
Door Alarm
-This circuit emits a beep and/or illuminates a LED when someone touches the door-handle from the outside. The alarm will sound until the circuit will be switched-off.
The entire circuit is enclosed in a small plastic or wooden box and should be hanged-up to the door-handle by means of a thick wire hook protruding from the top of the case.
A wide-range sensitivity control allows the use of the Door Alarm over a wide variety of door types, handles and locks. The device has proven reliable even when part of the lock comes in contact with the wall (bricks, stones, reinforced concrete), but does not work with all-metal doors.
The LED is very useful during setup.
Emergency Light and Alarm
-This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen.
When power supply is restored, the lamp or the alarm is switched-off. A switch provides a "latch-up" function, in order to extend lamp or alarm operation even when power is restored.
Fridge door Alarm (2nd Version)
-The main purpose of this design was to obviate a small defect of the very popular Fridge Door Alarm circuit.
A simple cure to this shortcoming could be the substitution of the original IC specified with a 74HC4060 chip: this should allow circuit operation down to 2V but, unfortunately, this IC is not easy to locate.
For this reason, an equivalent circuit using about the same electronic parts counting was developed, in order to allow safe operation even when battery voltage falls down to about 1.3V.
Water-level Alert project
-This circuit will emit an intermittent beep (or will flash a LED) when the water contained into a recipient has reached the desired level. It should be mounted on top of the recipient (e.g. a plastic tank) by means of two crocodile clips, acting also as probes. If a deeper sensing level is needed, the clips can be extended by means of two pieces of stiff wire