Circuit panel

Description

               Circuit showing a Burglar Alarm.Here we have used a ldr and a switching transistor for making this circuit
.When the light coming towards the ldr during the period the ldr have low resistance so the buzzer will on.When the light going away the ldr during the period the ldr have high resistance so the transistor will off.Here you need a 12 volt power supply

 Components Required

      Resistor

                   10 k(preset)

      Transistor


                   BC 548

       LDR


        Buzzer



Source by : http://www.electronics-circuits.in/2012/03/burglar-alarm-ldr-bc-548.html

This is a design circuit diagram of a light activated switch. This circuit is based on National Semiconductors comparator IC LM 311 and a LDR for operation. This is the figure of the circuit.


The circuit is based on a voltage comparator circuit wired around IC 1. The non-inverting in put of IC1 is given with a reference voltage of 6V using resistors R3 and R4. The input to the inverting input will be the voltage across the LDR that is light dependent. At darkness the resistance of the LDR will be high and so do the voltage across it. At this condition the voltage at the inverting input will be higher than the reference at non inverting pin and the out put of the comparator will be low(~o V). Adjust POT R1 to set the desired light intensity for switching the relay. For this illuminate the LDR with the desire intensity light.

The relay will be either on or off. Adjust POT R1 slowly so that the state of the relay changes. That’s it. Now the circuit is set for the given intensity of light. When the LDR is illuminated, its resistance drops and so do the voltage across it. Now the voltage at inverting input will be lower than that at non inverting input and the out put of the comparator goes high (~12 V). This makes transistor Q1 on and it drives the relay. As a result we get a relay switching according to the intensity of the light falling on the LDR.
You can use either a 12 V battery or a well regulated & filtered 12V DC mains operated power supply. The pin out of LM311 is also given together with the circuit diagram. The pin 5&6 (Balance & Balance/Strobe) of IC LM311 are shorted to minimize the chance of oscillations.

BURGLAR ALARM USING IC TIMER 555/556 ELECTRONIC DIAGRAM

The series of touch this switch be an Touch Switch made ​​using FET. This circuit serves to activate electronic devices only when we touch touch sensors.
Once we release a touch to the sensor, the electronic device that is connected is turned off again. The series of touch switch or touch switch is very simple, composed only of a FET, resistor and capacitor. The series of touch switches / touch switches work with source voltage 12VDC. Detailed series of touch switches / touch switch can be seen in thethe following figure .

FET Touch Switch

The series of touch switches / touch switch can only be used to illuminate DC, 12V DC lamp when it replaced the relay, the circuit can be used safely to load the AC network. Sensor touch to this series was made with 2 pieces of plate are arranged close together (within 1-2mm).

This circuit is which enables switching ‘on’ and ‘off’ of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls. The circuit described here can be used to switch up to nine appliances (corresponding to the digits 1 through 9 of the telephone key-pad). The DTMF signals on telephone instrument are used as control signals. The digit ‘0’ in DTMF mode is used to toggle between the appliance mode and normal telephone operation mode. Thus the telephone can be used to switch on or switch off the appliances also while being used for normal conversation. The circuit uses IC KT3170 (DTMF-to-BCD converter), 74154 (4-to-16-line demulti-plexer), and five CD4013 (D flip-flop) ICs.


The working of the circuit is as follows. Once a call is established (after hearing ring-back tone), dial ‘0’ in DTMF mode. IC1 decodes this as ‘1010,’ which is further demulti-plexed by IC2 as output O10 (at pin 11) of IC2 (74154). The active low output of IC2, after inversion by an inverter gate of IC3 (CD4049), becomes logic 1. This is used to toggle flip-flop-1 (F/F-1) and relay RL1 is energized. Relay RL1 has two changeover contacts, RL1(a) and RL1(b). The energized RL1(a) contacts provide a 220-ohm loop across the telephone line while RL1(b) contacts inject a 10kHz tone on the line, which indicates to the caller that appliance mode has been selected. The 220-ohm loop on telephone line disconnects the ringer from the telephone line in the exchange. The line is now connected for appliance mode of operation. If digit ‘0’ is not dialed (in DTMF) after establishing the call, the ring continues and the telephone can be used for normal conversation. After selection of the appliance mode of operation, if digit ‘1’ is dialed, it is decoded by IC1 and its output is ‘0001’. This BCD code is then demulti-plexed by 4-to-16-line demulti-plexer IC2 whose corresponding output, after inversion by a CD4049 inverter gate, goes to logic 1 state. This pulse toggles the corresponding flip-flop to alternate state. The flip-flop output is used to drive a relay (RL2) which can switch on or switch off the appliance connected through its contacts. By dialing other digits in a similar way, other appliances can also be switched ‘on’ or ‘off’.

Once the switching operation is over, the 220-ohm loop resistance and 10kHz tone needs to be removed from the telephone line. To achieve this, digit ‘0’ (in DTMF mode) is dialed again to toggle flip-flop-1 to de-energize relay RL1, which terminates the loop on line and the 10kHz tone is also disconnected. The telephone line is thus again set free to receive normal calls. This circuit is to be connected in parallel to the telephone instrument

The
two seven segment LED displays are multiplexed together and their data
lines are connected to Port0  of the microcontroller. Transistors Q1
and Q2 drives the corresponding displays D1 and D2. The driving signals
for there transistors are obtained from P1.1 and P1.2. Push button
switch S1,capacitor C1 and resistor R10 forms a debouncing reset
circuit. Resistor R9, capacitor C2 and pushbutton switch S2 will
provide an active low harware  interrupt signal at INTO (pin12) when
ever S2 is pressed. Here also R9 and C2 are meant for debouncing. After
power ON the display will show blank and when push button S2 is
pressed the display will show a random number between 0 and 99. For
another try you have to press the reset switch and then switch S2. If
you need a single digit setup only, the remove display D2 and
its associated components. Everything else is same.

ORG 000H
SJMP MAIN
ORG 003H // sets the starting address for the ISR
ACALL ISR // calls the ISR subroutine when S2 is pressed
RETI // return from interrrupt

MAIN:SETB IP.0 // this part sets the initial conditions
     SETB TCON.0
     SETB IE.0
     SETB IE.7
     MOV P0,#00000000B
     MOV P1,#00000000B
     MOV DPTR,#LUT // moves the starting address of LUT to DPTR

LABEL:MOV R6,#99D // this part generates the random number
      LOOP:MOV A,R6
      DJNZ R6,LOOP
      SJMP LABEL

ISR: MOV A,R6 // Subroutine ISR displays the current random number
     MOV B,#10D
     DIV AB
     SETB P1.2
     ACALL DISPLAY
     MOV P0,A
     ACALL DELAY
     MOV A,B
     CLR P1.2
     SETB P1.1
     ACALL DISPLAY
     MOV P0,A
     ACALL DELAY
     CLR P1.1
     SJMP ISR
     RET

DELAY: MOV R3,#02H // this subroutine creates 1mS delay for switching the displays
DEL1: MOV R2,#0FAH
DEL2: DJNZ R2,DEL2
      DJNZ R3,DEL1
      RET

DISPLAY: MOVC A,@A+DPTR // produces the digit drive pattern for the current digit in A
         RET

LUT: DB 3FH // Look up table
     DB 06H
     DB 5BH
     DB 4FH
     DB 66H
     DB 6DH
     DB 7DH
     DB 07H
     DB 7FH
     DB 6FH
     END

The
first part of the program is the portion labelled MAIN which sets the
initial conditions and the interrupt parameters. The next part is the
loop named LABEL which loads 99D to register R6  then decrements it by 1
until 0 and then repeats the cycle again. This is the part which
generates the random number. Every time R6 is decremented the resultant
value is moved to accumulator A. Next part is the interrupt service
routine which is written as a subroutine named ISR. When ever there is
an interrupt at INT0 (push button S2 is pressed), the ISR is called.
The ISR perfoms necessary mathematical manipulations on the content of A
in order to split out the two digits and then proceeds to show it on
the display. Subroutine DELAY produces roughly 1ms delay for switching
the displays. Subroutine DISPLAY adds the current value in A with the
address stored in DPTR (starting address of LUT) and moves the target
content to A. The result will be the digit drive pattern for the
current digit in A.

This is a simple LED flasher project that uses a common 555 timer IC for its operation. It is configured as an astable mode which means that its output is a square wave oscillator. Two LEDs are connected to its output in such a way that when one LED is ON, the other LED will turn OFF. 

It uses only 10 simple parts that are easily available at any electronic shops. Capacitor C2 charges exponentially through resistors R1, R2 and the resistance of the trimpot. When C2 has charged to about 2/3 VCC it stops charging and it discharges to about 1/3 VCC through R2 and the trimpot resistance via pin 7. This is the standard operation of a 555 timer. When a Vcc of 5 V to 15 V DC is applied to the circuit, the LED will start to flash.

The frequency of the flashing can be changed by varying the resistance of the potentiometer or trimpot.Parts List The parts list of the simple LED project is as shown below.

This is a design circuit diagram of an infrared motion detector that can be used to sense intrusions. Infra red rays reflected from a static object will be in one phase, and the rays reflected from a moving object will be in another phase. The circuit uses this principle to sense the motion. This circuit is work based on LM11458 IC as the controller of the circuit. This is the figure of the circuit.


The operation of the circuit is the following. The IC1 (NE 555) is wires as an astable multi vibrator .The IR diode connected at the output of this IC produces infrared beams of frequency 5Khz. These beams are picked by the photo transistor Q1. At normal condition, when there is no intrusion the output pin (7) of IC2 will be low. When there is an intrusion the phase of the reflected waveforms has a difference in phase and this phase difference will be picked by the IC2. Now the pin 7 of the IC 2 goes high to indicate the intrusion. An LED or a buzzer can be connected at the output of the IC to indicate the intrusion. Comparators IC2a and IC2b are belonging to the same IC2 (LM11458). So the power supply is shown connected only once. When there is disturbance in the air or vehicles passing nearby, the circuit may get false triggered. POT R5 can be used for sensitivity adjustment.