Burglar Alarms circuit and explanation
For those who want the effort to prevent theft in the neighborhood, home burglar alarms become an important tool. To realize an alarm s
ystem for your home can be complicated and expensive. Many home security systems are offered ranging from sirens to the video monitor, but still must consider the cost should be excluded.
This page does not mean to do not care about safety, just trying to explain in simple information on how to design home burglar alarms base
d on the following circuit with several features that are pretty good if you want to build it.
Simple Home Burglar Alarm Circuit
The following home burglar alarm circuit using the active components 4011 CMOS IC and transistor BC547 with features, including automatic Exit and Entry delay and timed Bell / Siren Cut-Off. This home burglar alarm circuit is des
igned for use with the ordinary-type input device is usually covered such as – magnetic reed contacts – micro switches – foil tape – and PIRs.
Home Burglar Alarm Circuit
Home Burglar Alarm Circu
it Parts List
Transistor BC547
Diodes 1N4148
CMOS 4011
Capacitor Electrolytic 25 Volt
C2 100 uF
C3 220 uF
C5 100 uF
Capacitors Ceramic 63 Volt
C1 100n
C4 100n
Resistor 0.25 watt
3 x 1k
4 x 2k7
2 x 330k
1 x 4M7
Simple Home Burglar Alarm Using SCR
This home burglar alarm circuit is a loud alarm at the break of the daylight. It uses a 555 timer IC that has a function as an astable multivibrator at a frequency of about 1kHz. Home burglar alarm is placed in a specific space, like cupb
oards as an anti-burglar alarm. The alarm is activated when the cupboard is open when the light will hit the circuit.
When no light falls on the LDR, the transistor is pulled high by the variable resistor. Hence the transistor is OFF and the reset pin of the 555 is pulled low. Due the this the 555 is reset. When light falls on the LDR, its resistance decreases and pulls the bases of the transistor low hence turning it ON. This pulls the reset pin 4 of the 555 high and hence enables the 555 oscillator and a sound is produced by the speakers. The 100K variable resistor has to be adjusted to set the light intensity that triggers the alarm.
