SECURITY ALARM Done by RINKESH KURKURE
This project serves as a detecting mechanism to indicate the presence of an object or person in undetected cases. This system uses an LED transmitter and LDR sensor unit to identify the arrival of a person It makes a beep sound using a buzzer.
This is basically a detecting mechanism project. This system switches on the gate light when surrounding light is HIGH. It helps a lot in saving electricity.
This circuit has two stages. Transmitting unit and receiving unit. Transmitting unit consists of LED Receiving unit consists of LDR sensor.
IC 555 TIMER
An IC 555 working in mono stable mode gives the time delay. IC 555 is a highly stable controller capable of producing accurate timing pulses. It can operate with a supply voltage in the range of 4.5 to 18V.
It is a pulse generating circuit. The duration of this pulse is determined by the RC network connected externally to the 555 timer. In a stable state, the output of the circuit is approximately zero or a logic-low level.
When external trigger pulse is applied output is forced to go high (» VCC) At the end of the timing interval, the output automatically drawn back to its low stable state.
It is a two stage switching circuit. This free running multi-vibrator generates square wave without any external triggering pulse. It switches back and forth from one state to another. It remains in each state for a time depending upon the discharging of the capacitive circuit
L D R L I G H T D E P E N D E N T R E S I S T O R
AAn LDR is a variable resistor. IIts value decreases with increasing incident light intensity. AAnd it conducts when light falls on it.
It can have a wide range of resistance. In bright light resistance is less than 100Ω & in darkness its excess of 10 MΩ. The cells are capable of reacting to a broad range of frequencies, including infrared (IR), visible light, and ultraviolet (UV).
When the light source to the semiconductor is interrupted by a person walking through the beam of light, a switch is activated that triggers the alarm. Burglar alarms sometimes have electric eyes that operate on the principle of photoconductivity.
In an image u can see that when a light falls on LDR the LED glows it is a basic principle of its working.
RELAY
A relay is an electrically operated switch. It can be used to electrically isolate different parts of a circuit When electricity flows through a coil, it becomes an electromagnet. Relays allow one circuit to switch a second circuit which can be completely separate from the first.
The switch's motion (ON and OFF) is controlled by the current flowing to the coil, or not.
CIRCUIT DIAGRAM
Home and business owners can now choose a new type of keypad control panel designed to help reduce false alarms. Newer model alarms have technology to measure the size/weight of the object causing the disturbance so we are able to decide how serious the threat is. When we use high intensity alarms it turns out to be a domestic as well as security purpose project.
The project provides the detecting mechanism of objects or person at unexpected timings. It has the advantage of saving of electricity since the bulb glows in the dark only for a short interval of time. Another main advantage is the height adjusting mechanism which we could implement.
ADVANTAGES High sensitivity Low cost Simple construction Easy to install and maintain Less power consuming Requires less space Reliable
Thank You