Refrigerator Door Alarm Circuit Using LDR

The alarm circuit enclosed into a small box is placed in the refrigerator near the lamp. With the door closed the interior of the refrigerator is in the dark, the LDR R2 presents a high resistance thus clamping IC1 by holding pin 12 high. When a beam of light enters from the opening, or the refrigerator lamp illuminates, the LDR lowers its resistance, pin 12 goes low, IC1 starts counting and, after a preset delay (20 seconds in this case) the piezo sounder beeps for 20 sec. then stops for the same lapse of time and the cycle repeats until the refrigerator door closes. D2 connected to pin 6 of IC1 allows the piezo sounder beeping 3 times per second.

Skema Rangkaian Refrigerator Door Alarm Using LDR

Note:

• Delay time can be varied changing C1 and/or R3 values.
• Quiescent current drawing is negligible, so SW1 can be omitted.
• Place the circuit near the lamp and take it away when defrosting, to avoid circuit damage due to excessive moisture.
• Do not put this device in the freezer.

List Component:

R1    : 10K
r2    : LDR any type
R3,R4 : 100K
C1    : 10nF
C2    : 100µF/25V
D1,D2 : 1N4148
IC1   : 4060 14 stage ripple counter and oscillator IC
Q1    : BC337
BZ1   : Piezo sounder (incorporating 3KHz oscillator)
SW1   : SPST slide Switch
B1    : 3V Battery

This alarm circuit from : http://www.redcircuits.com/

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Water Activated Alarm Using IC 555 Circuit

This Water Activated Alarm circuit uses a NE555 timer wired as an astable oscillator and powered by the emitter current of the transistor BC109C. Under dry conditions, the transistor will from have no bias current and be fully off. As the probes get wet, a small current flows Between the base and emitter and the transistor switches on. A larger current flows in the collector circuit enabling the IC NE555 osillator to sound.

Skema Rangkaian Water Activated Alarm

Probe/contacts may use a non-reactive metal. 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 the 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).

Circuit from: www.epanorama.net

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IC 555 Motorcycle Alarm Circuit

Rangkaian Motorcycle Alarm

This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike, flash the lights etc. I have used Andy's Asymmetric Timer as the basis for this design.

Skema Rangkaian IC 555 Motorcycle Alarm

Any number of normally-open switches may be used. Fit "tilt" switches that 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.

The alarm's standby current is virtually zero - so it won't drain your battery. Once activated - the rate at which the siren switches on and off is controlled by R7, R8 & C4. For example, increasing R7 will make the sound period longer - while increasing R8 gives longer silent periods.

The circuit is designed to use an electronic Siren drawing 300 to 400mA. It's not usually a good idea to use the bike's own Horn because it can be easily located and disconnected. However - if you choose to use the Horn - remember that the alarm relay 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, flash the lights etc.

The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Connect 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 alarm. Exactly how the system is fitted will depend on the make of your particular machine - so I'm unable to provide any further help or advice in this regard.

When you set the alarm - if one of the switches is closed - the siren will sound. This could cause annoyance late at night. A small modification will allow you to Monitor The State Of The Switches using LEDs. When the LEDs are all off - the switches are all open - and it's safe to turn the alarm on


Source: http://www.zen22142.zen

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Rangkaian Alarm Kebakaran

Alarm Kebakaran

This is a simple fire alarm circuit, which can help the user's color interested against fire accidents based on a LDR and lamp pairs an alarm for sensing the fire.The works by sensing the smoke Produced During fire.The circuit produces an audible alarm the fire breaks Pls out with smoke.

Skema Rangkaian Alarm Kebakaran

When a number of smoke passes Between a bulb and an LDR, the amount of light falling on the LDR decreases. This Causes the resistance of the LDR to Increase and the voltage at the base of the transistor is pulled high due to Which the supply to the COB (chip-on-board) is completed. Different cobs are available in the market to generate Different Musical. The choice of the COB depends on the user. The signal generated by COB is amplified by an audio amplifier. In this circuit, the audio power amplifier is wired around TDA2002. The sensitivity of the circuit depends on the distance Between bulb and LDR as well as the setting of preset VR1. Thus by placing the bulb and the LDR at appropriate distances, one May Vary preset VR1 to get optimum sensitivity. An ON / OFF switch is suggested to turn the circuit on and off as Desirable.

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Rangkaian Alarm|Sensor Cahaya

Alarm|Sensor Cahaya

This circuit is a loud alarm at the break of the daylight. The 555 timer IC is Used here. It is working as an astable multivibrator at a frequency of about 1kHz. This circuit can be used as an anti-burglar alarm in certain rooms, such as cupboard, cupboard in the open when the light will hit the circuit, so the alarm will be activated

Rangkaian Alarm|Sensor Cahaya

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.

IC 555 Pinning

function of each pin:

1. Ground, is the input pin of the negative DC voltage source
2. Trigger, the lower the negative input comparator (comparator B) that maintain low voltage oscillation capacitor in third Fcc and set RS flip-flop
3. Output, the output pin of the IC 555.
4. Reset, the pin which serves to reset the latch inside the IC which will affect the work to reset IC. This pin is connected to a PNP-type transistor gate, so the transistor will be active if given a logic low. Normally this pin is connected directly to avoid reset Fcc
5. Control Voltage, this pin serves to regulate the stability of the negative reference voltage input (comparator A). This pin can be left hanging, but to ensure the stability of the reference comparator A, usually associated with the order of about 10nF capacitor to pin groun
6. Threshold, this pin is connected to the positive input (comparator A) which will reset the RS flip-flop when the voltage on the capacitor started to exceed 2 / 3 Vc
7. Discharge, this pin is connected to an open collector transistor Q1 is connected to ground emitternya. Switching transistor serves to clamp the corresponding node to ground at a certain timing
8. VCC, this pin to receive a DC voltage supply. Usually will work optimally if given a 5-15V. the current supply can be viewed in a datasheet, which is around 10-15mA.

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Monitor|Sensor Arus AC Menggunakan LED

Monitor|Sensor Arus AC

This circuit functions to remotely monitor Pls help a couple of electric heaters have been left on. Its sensors must be placed in contact with the feeders to be Able to monitor Pls the power cable is drawing current, Thus causing the circuit to a switch-on LED. The circuit and its coil sensor Can be placed very far from the actual load, provided an easy access to the power cable is available.

Any type of high-current load or group of loads Can be monitored, eg: heaters, motors, washing machines, dish-washers, electric ovens. Etc., provided they want dissipate a power comprised in the 0.5 at least - 1KW range. This design features three versions. The basic one illuminates a LED Pls the load is on. The second version Pls drives a relay a pre-set current value flows into the power cable. The third version Pls D7 switches-on the load power is about 1KW, D6 Pls the load power is about 2KW and D5 Pls the load power is about 3KW

Skema Rangkaian Monitor|Sensor Arus AC

Notes:

• The pick-up coil L1 is a common 10mH miniature inductor. This inductor must be placed tightly against one wire of the power cable, leaving the other wire some centimeters apart.
• The sensitivity will be doubled if the inductor is placed tightly between the two wires as shown in the diagram, top left. On the contrary, do not place the inductor against paired wires as the signal tends to cancel and the circuit will not work.
• The LED limiting resistor R5 should have a value comprised in the 100R - 1K range, depending on the output voltage obtained.
• LED D1 and its limiting resistor R5 can be omitted in versions two and three of the circuit.

List Component

R1,R2,R8____________1K 1/4W Resistors
R3,R4_____________220K 1/4W Resistors
R5________________100R 1/4W Resistor
R6_________________10K 1/2W Trimmer
R7,R10______________1M 1/4W Resistors
R9_________________22K 1/2W Resistor
R11 to R17__________1K 1/4W Resistors
C1,C3_____________100Î…F 25V Electrolytic Capacitors
C2,C4_______________1Î…F 63V Electrolytic Capacitors
D1________________5mm. Red LED
D3,D4___________1N4002 100V 1A Diodes
D2,D5,D6,D7_______LEDs (Any color and size)
Q1_______________BC327 45V 800mA PNP Transistor
IC1______________TL061 Low current BIFET Op-Amp
IC1______________LM358 Low Power Dual Op-amp
IC1______________LM324 Low Power Quad Op-amp
L1________________10mH miniature Inductor
RL1______________Relay with SPDT 2A @ 220V switch
Coil Voltage 12V. Coil resistance 200-300 Ohm
J1_______________Two ways output socket



Source

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Rangkaian ALarm|Sirine Berbasis SCR

ALarm|Sirine Berbasis SCR

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.

Skema rangkaian alarm|sirine

SCR-based alarm circuit is It's easy to use. When you switch on the alarm - 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.

After about 10 minutes - the alarm will attempt to reset itself. If the trigger circuit has been restored - the attempt will be successful. But - if the loop is still open - the attempt will fail - and the alarm will re-activate. Of course - you can turn the Siren off at any time by switching off the alarm.

A conventional bell uses up to about 400mA. An electronic siren generally uses less. If you intend to draw a heavier current from either the Buzzer or Siren terminals - the SCR in question will need to be bolted to a metal heatsink - and the relay contacts may need upgrading.

If you do not want the timed "cut-off and reset" feature - leave out D5, D6, R11, R12, Q3, Q4, C6 and the relay.


Source

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Rangkaian Alarm Pintu Rumah

Rangkaian Alarm Pintu

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.

Q1 forms a free-running oscillator: its output bursts drive Q2 into saturation, so Q3 and the LED are off. When part of a human body comes in contact with a metal handle electrically connected to the wire hook, the body capacitance damps Q1 oscillations, Q2 biasing falls off and the transistor becomes non conducting. Therefore, current can flow into Q3 base and D3 illuminates. If SW1 is closed, a self-latching circuit formed by Q4 & Q5 is triggered and the beeper BZ1 is activated.When the human body part leaves the handle, the LED switches-off but the beeper continues to sound, due to the self-latching behavior of Q4 & Q5. To stop the beeper action, the entire circuit must be switched-off opening SW2. R3 is the sensitivity control, allowing to cope with a wide variety of door types, handles and locks.

Skema rangkaian alarm pintu rumah

Note:

• L1 is formed winding 20 to 30 turns of 0.4mm. diameter enameled copper wire on R2 body and soldering the coil ends to the resistor leads. You should fill R2 body completely with coil winding: the final turns' number can vary slightly, depending on different 1 or 2W resistor types actual length (mean dimensions for these components are 13 - 18mm. length and 5 - 6mm. diameter).
• The hook is made from non-insulated wire 1 - 2mm. diameter (brass is well suited). Its length can vary from about 5 to 10cm. (not critical).
• If the device is moved frequently to different doors, Trimmer R3 can be substituted by a common linear potentiometer fitted with outer knob for easy setup.
• To setup the device hang-up the hook to the door-handle (with the door closed), open SW1 and switch-on the circuit. Adjust R3 until the LED illuminates, then turn slowly backwards the screwdriver (or the knob) until the LED is completely off. At this point, touching the door-handle with your hand the LED should illuminate, going off when the hand is withdrawn. Finally, close SW1 and the beeper will sound when the door-handle will be touched again, but will not stop until SW2 is opened.
• In regular use, it is advisable to hang-up and power-on the device with SW1 open: when all is well settled, SW1 can be closed. This precautionary measure is necessary to avoid unwanted triggering of the beeper.

Component List

R1______________1M 1/4W Resistor
R2______________3K3 1 or 2W Resistor (See Notes)
R3_____________10K 1/2W Trimmer Cermet (See Notes)
R4_____________33K 1/4W Resistor
R5____________150K 1/4W Resistor
R6______________2K2 1/4W Resistor
R7_____________22K 1/4W Resistor
R8______________4K7 1/4W Resistor
C1,C2__________10nF 63V Ceramic or Polyester Capacitors
C3_____________10pF 63V Ceramic Capacitor
C4,C6_________100nF 63V Ceramic or Polyester Capacitors
C5______________2µ2 25V Electrolytic Capacitor
C7____________100µF 25V Electrolytic Capacitor
D1,D2,D4_____1N4148 75V 150mA Diodes
D3_____________5 or 3mm. Red LED
Q1,Q2,Q3,Q5___BC547 45V 100mA NPN Transistors
Q4____________BC557 45V 100mA PNP Transistor
L1_________________ (See Notes)
L2_____________10mH miniature Inductor
BZ1___________Piezo sounder (incorporating 3KHz oscillator)
SW1,SW2________SPST miniature Slider Switches
B1_______________9V PP3 Battery

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Rankaian Alarm Anti Pencuri Barbasis FM Radio

Alarm Anti Pencuri Barbasis FM Radio

This Circuit of FM radio-controlled anti- theft alarm can be used with any vehicle having 6- to 12-volt DC supply system. The mini VHF, FM transmitter is fitted in the vehicle at night when it is parked in the car porch or car park.

Skema Rankaian Alarm Anti Pencuri Barbasis FM Radio

The receiver unit with CXA1019, a single IC-based FM radio module, which is freely available in the market at reasonable rate, is kept inside. Receiver is tuned to the transmitter's frequency. When the transmitter is on and the signals are being received by FM radio receiver, no hissing noise is available at the output of receiver. Thus transistor T2 (BC548) does not conduct. This results in the relay driver transistor T3 getting its forward base bias via 10k resistor R5 and the relay gets energised. When an intruder tries to drive the car and takes it a few metres away from the car porch, the radio link between the car (transmitter) and alarm (receiver) is broken. As a result FM radio module gene-rates hissing noise. Hissing AC signals are coupled to relay switching circ- uit via audio transformer.

These AC signals are rectified and filtered by diode D1 and capacitor C8, and the resulting positive DC voltage provides a forward bias to transistor T2. Thus transistor T2 conducts, and it pulls the base of relay driver transistor T3 to ground level. The relay thus gets de-activated and the alarm connected via N/C contacts of relay is switched on. If, by chance, the intruder finds out about the wireless alarm and disconnects the transmitter from battery, still remote alarm remains activated because in the absence of signal, the receiver continues to produce hissing noise at its output. So the burglar alarm is fool-proof and highly reliable.

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Rangkaian Sound Effects Generator

This is a sound effects generator circuit used IC HT2884. There are 8 different sound effect can be produced that are 2 lazer guns, 1 dual tone horn sound, 2 bomb sounds, 2 machine gun sounds and a rifle shot sound.

Skema rangkaian sound effects generator

Power is a 3 Volt battery, but the IC will work with any voltage between 2.5 - 5 Volts. Switch S1 is the on / off switch. The output at pin 10 is amplified and drives a small 8 ohm loudspeaker. Pressing S3 once will generate all the sounds, one after another. S2 can be used to produce a single sound effect, next depression gives the next sound effect. Standby current is about 1 uA at 3 Volt, so battery life is very economical.

IC HT2844 Description

The IC HT2844 is a CMOS LSI chip designed for use in sound effect products. It is equipped with tone circuit, noise circuit, and other control logic to generate various sounds including rifle gun, machine gan, booming, door bell, alarm, and so forth. the feature of the customer's sound source can be analyzed and programmed into an internal ROM by changing a mask layer durimg device fabrication

Absolute maximum rating
Supply voltage....................................... 03 to 5 Volt.
Input voltage.......................................... Vss - 0.3 to VDD+0.3 Volt.
Storage temperature.............................. -50 to 125 C.
Operating temperature........................... 0 to 70 C.
.

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Rangkaian Sirine Sederhana 2 Transistor

This is a simple Siren circuit used 2 transistor . The siren circuit produced imitates the rise and fall of an American police siren. When first switched on the 10u capacitors is discharged and both transistors are off. When the push button switch is pressed to 10u capacitor will charge via 22k resistor. This voltage is applied to the base of the BC108B which will turn on slowly. When the switch is released the capacitor will discharge via the 100k and 47k base resistors and the transistor will slowly turn off. The change in voltage alters the frequency of the siren.

Skema rangkaian sirine sederhana

Current drain is fairly high in this circuit so a suitable power supply is required. The duration the tone takes to rise and fall is determined by the 10u and 22k resistor. These values may be varied for different effects.

Transistor 2N3702 description

This device designed for use as PNP general purpose amplifier and switches requiring collector currents to 300mA.



Absolute Maximum Ratings

• Collector-Emitter Voltage (VCEO ): -25 V.
• Collector-Base Voltage (VCBO ): -40 V.
• Emitter-Base Voltage (VEBO ): -5.0 V.
• Collector Current - Continuous (IC): -500 mA.
• Operating and Storage Junction Temperature Range (TJ, TST): -55 ~ +150 C.
• Current Gain (hFE DC ): 60 - 300.

Pin transistor BC 108

• Low current (max. 100 mA).
• Low voltage (max. 45 V).
• Current Gain (hFE DC) : 110 - 450.

.

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Rangkaian Pembangkit Suara Burung

This generate a sound like bird’s circuit. The trafo LT700 is a small audio transformer with primary is center tapped with an impedance of 1Kohms at 1KHz . The secondary has an impedance of 8 ohms.

Skema rangkaian pembangkit suara burung

The inclusion of R1 and C1 give this oscillator its characteristic “chirp”. As the 100u capacitor charges via the 4.7K resistor, R1 the bias for the transistor is cut off. This causes the oscillation to stop, the capacitor discharges through the base emitter circuit of the transistor and oscillations start again. Altering these components alters the frequency of the chirp. The chirp is also voltage dependent. When the push button switch is operated the 100u capacitor is charged. When its released, the oscillation decays and the chirp becomes faster.


Transistor BC177 description

NPN transistor in a TO-18; SOT18 metal package. PNP complement: BC177.

Data reverence Transistor BC177

• VCBO/ collector-base voltage open emitter: 30 V
• VCEO/ collector-emitter voltage open base: 20 V
• VEBO/ emitter-base voltage: 5 V
• ICM/ peak collector current - 200 mA
• Ptot/ total power dissipation Tamb £ 25 °C - 300 mW
• hFE DC current gain IC = 2 mA; VCE = 5 V: min 200 max 800
• fT transition frequency IC = 10 mA; VCE = 5 V; f = 100 MHz: min 100 MHz
• Tstg/ storage temperature: Min -65 max +150 °C
• Tj/ junction temperature max 175 °C
• Tamb/ operating ambient temperature min -65 max +150 °C

LT700 Tranformer is a small audio transformer with primary is center tapped with an impedance of 1Kohms at 1KHz . The secondary has an impedance of 8 ohms.

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Rangkaian Bell Pintu Rumah

This is a doorbell circuit use IC NE555.When some one presses switch S1 momentarily, the loud speaker sounds a bell tone as long as the time period of the monostable multivibrator (IC1). When the switch S1 pressed, IC1 is triggered at its pin 2 and output pin 3 goes high for a time period previously set by the values of POT R4 and POT R5.When the output of IC1 goes high it resets IC2 and it starts to oscillate to make a bell sound through the speaker.The IC2 is configured as an astable multivibrator whose oscillation frequency can be varied with the help of POT R5.By adjusting the values of R4 & R5, modifications on the tone are possible.

Skema rangkaian bell pintu

IC NE555 description

The NE555 monolithic timing circuit is a highly stable controller capable of producing accurate time delays or oscillation. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For a stable operation as an oscillator, the free running frequency and the duty cycle are both accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200mA. The NE555 is available in plastic and ceramic minidip package and in a 8-lead micropackage and in metal can package version.

Lay out and diagram IC NE555

Pin connnections IC NE555

1 - GND
2 - Trigger
3 - Output
4 - Reset
5 - Control voltage
6 - Threshold
7 - Discharge
8 – VCC

Absolute maximum ratings
Supply Voltage: 18 V
Operating Free Air Temperature Range for NE555: 0 to 70 oC
Junction Temperature 150 oC
Storage Temperature Range –65 to 150 oC.
.

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Rangkaian Ding dong bel Rumah

This simple circuit an low cost ding dong bell suitable for calling bell purposes. It is made around IC 8021-2 . IC 8021 has an in-built circuitry to produce ding dong sound each time its pin 3 is pulled low. The sound is stored in a 4 bit ROM.a complementary-pair, two-transistor amplifier is used to amplify the sound to a fair level of audibility. A piezo tweeter or an 8-ohm, 500mW speaker can be used at the output.

Skema Rangkaian bel Rumah

List Component bel Rumah:
R1: 1K 1/4W Resistance
C1: 10µF/12-25V Electrolytic Capacitance
T1: BC548/c8050 NPN transistor
T2: BC557/C8550 PNP transistor
IC1: 8021-2 ding dong sound generator
Ls1: Speaker tweeter 500 Mwatt - 5 watt
S1: switch on/off
S2: Switch Normally close
B1: 3V Cell

Each time when switch S2 is pressed, ding dong sound is produced twice. If you try to press switch S2 a second time when the first ding dong sound is still being produed, it has no effect whatever and the two ding-dong bell sounds will be invariably produced.S1 is the ON- OFF switch.Assemble the circuit on a good quality all pupose PCB.Don’t forget to use an IC holder for IC 8021.

IC 8021 Description

The 8021-2 is a ding-dong sound effect generator IC produced by LSI CMOS technology. With built-in RC oscillator and digital envelope circuits, minimal external components are required. This IC simulates the mechanical ding-dong sound, and is ideal for door bell application.

IC 8021 Features
- 1.3V to 3.3V operating voltage and low power consumption
- One-shot mode of 2 ding-dong playing sequences
- Standard TO-92 package form
- Dynamic speaker can be driven with external NPN transistor

IC 8021 Absolute Maximum Ratings
DC Supply Voltage ........................................... -0.3V to +5.0V
Operating Ambient Temperature .................... -10°C to 60°C
Storage Temperature ....................................... -55°C to 125°C

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Rangkaian Alarm LDR anti maling

Anti-theft alarm circuit it produces an audible alarm when fridge is left open for a preset time.Rangkaian This versatile alarm is based on two 555 timer IC's. Both ICS are wired as astable Multivibrators.An LDR is connected in parallel to the timing capacitor

C1 of IC 1.When is completely close door there will be no light inside the fridge and offers high resistance LDR R1 keeping fully charged.When door is left open, the lamp inside the fridge will remain glown, LDR will be illuminated, and its falls.This resistance makes
C1 stops charging and starts to discharge (In simple words, this is because at low resistance LDR bye passes much of the current in the parrallel path and capacitor gets less current). Now IC 1 starts oscillating slightly and after a preset time of 25 ( time T1) seconds high.This its output goes out put makes the Ic 2 to produce oscillations and results in a beeping sound for next 20 (time T2) seconds and cycle is repeated till door is closed.

Skema Rangkaian Alarm anti maling

List Component alarm anti maling:

• R1: 10K 1/4W Resistance
• R3: 2.2 M 1/4W Resistance
• R4: 1M 1/4W Resistance
• C1: 10µF/25V Electrolytic Capacitance
• C2: 100nF/63V Polyester Capacitance
• D1: 1N4001 Diode
• IC1,IC2: NE 555 Timer ICs
• BZ1: Piezo Buzzer
• B1: 3V Cell

Note:

Assemble the circuit on a good quality PCB .Time T1 & T2 can be adjusted by varying C1, C2, R1, R4 etc (Refer data sheet of 555). Place the LDR close enough to the lamp inside the fridge.

IC 555 Pin No Designation Description

1. Ground, is the input pin of the source of the negative DC voltage
2. Trigger, negative input from the lower comparators (comparator B) that maintain oscillation capacitor voltage in the lowest 1 / 3 Vcc and set RS flip-flop
3. Output, the output pin of the IC 555.
4. Reset, the pin that serves to reset the latch inside the IC to be influential to reset the IC work. This pin is connected to a PNP-type transistor gate, so the transistor will be active if given a logic low. Normally this pin is connected directly to Vcc to prevent reset
5. Control voltage, this pin serves to regulate the stability of the reference voltage negative input (comparator A). This pin can be left hanging, but to ensure the stability of the reference comparator A, usually associated with a capacitor of about 10nF to berorde pin groun
6. Threshold, this pin is connected to the positive input (comparator A) which will reset the RS flip-flop when the voltage on the capacitor from exceeding 2 / 3 Vc
7. Discharge, this pin is connected to an open collector transistor Q1 is connected to ground emitternya. Switching transistor serves to clamp the corresponding node to ground on the timing of certain
8. Vcc, pin it to receive a DC voltage supply. Usually will work optimally if given a 5-15V. the current supply can be seen in the datasheet, which is about 10-15mA.

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Rangkaian Pembangkit Melody|Musik Mainan

Circuit of musik|melody generator you can make using an IC.The UM66 series are CMOS IC’s designed for using in calling bell, phone and toys. It has a built in ROM programmed for playing music. The device has very low power consumption.Thanks for the CMOS technology.The melody will be available at pin3 of UM66 and here it is amplified by using transistor Q1 dan Q2 to drive the speaker.

Skema Rangkaian Pembangkit Melody Mainan

UM66 is a pleasing music generator IC which works on a supply voltage of 3V. the required 3V supply is given through a zener regulator. its out put is taken from the pin no1 and is given to a push pull amplifier to drive the low impedance lowd speker. A clss A amplifier before pushpull amplifier can be used to decrese the noise and improve out put. UM66 is a 3 pin IC pakage just looks like a BC 547 transistor.

Notes

• Power supply must be between 6V - 15V .
  
• Melody begins from the first note if power is reseted.
• Assemble the circuit on a good quality common board.

IC UM66 Description

The U66 series is a CMOS LSI designed melody generator IC for use in telephones and toys application. It has an on-chip ROM programmed for musical performance. Produced by CMOS technology, the device results in very low power consumption. And with built-in RC oscillator, a compact melody module can be constructed with only a few additional components.

Pin No Designation Description
-1. Out put Melody out put
-2. +Vdd Positive power supply
-3. -Vss Negative Power supply

Features of UM66T series
-62 Note ROM Memory
-Voltage rating: 1.3V to 3.3 V
-Power on reset
-

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Rangkaian Alarm pendeteksi Api menggunakan LDR

In the rooms are vulnerable to fire, such as a storage material flammable, required a system of prevention of the occurrence of fire. For example, using a fire alarm, so that eg arise if a flame, can be quickly and by others that can immediately fire it does not cause a fire is greater.

Here is a simple fire alarm circuit based on a LDR and lamp pair for sensing the fire.The alarm works by sensing the smoke produced during fire.The circuit produces an audible alarm when the fire breaks out with smoke.

Skema rangkaian alarm pendeteksi api|kebakaran

Note:

• The speaker can be a 8Ω tweeter.
• POT R4 can be used to adjust the sensitivity of the alarm.
• POT R3 can be used for varying the volume of the alarm.
• Any general purpose NPN transistor( BC548,BC148,2N222) can be used for Q1.
• The circuit can be powered from a 9V battery or a 9V DC power supply.
• Instead of bulb you can use a bright LED with a 1K resistor series to it.

When there is no smoke the light from the bulb will be directly falling on the LDR.The LDR resistance will be low and so the voltage across it (below .6V).The transistor will be OFF and nothing happens.When there is sufficient smoke to mask the light from falling on LDR, the LDR resistance increases and so do the voltage across it.Now the transistor will switch to ON.This gives power to the IC1 and it outputs 5V.This powers the tone generator IC UM66 (IC2) to play a music.This music will be amplified by IC3 (TDA 2002) to drive the speaker.

The diode D1 and D2 in combination drops 1.4 V to give the rated voltage (3.5V ) to UM66 .UM 66 cannot withstand more than 4V.

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Skema Rangkaian Sirine Polisi

Rangkaian sirine police will produce sound that is almost similar to the sirens and the police can plug in the car or motorcycle. Rangkaina consists of 2 pieces IC NE 555 that serves as the frequency (multivibrator astable) that the frequency can be set to play Vr1 and Vr2.

Gamabar Skema Rangkaian Sirine Polisi

If the sound output in the less hard (loud) you can add a brace power amplifier that has a higher brace misalanya series amplifier LM386. series has a power output greater tegangn and have the same input. To install this series you just menghubungakan output rangkain sirens and then enter in to the input. Move the speaker to the output ampilifier LM386

functions of each pin IC 555:

IC 555 pic

• Ground, is the input pin of the source of the negative DC voltage
• trigger, negative input from the lower comparators (comparator B) that maintain oscillation capacitor voltage in the lowest 1 / 3 Vcc and set RS flip-flop
• output, the output pin of the IC 555.
• reset, the pin that serves to reset the latch inside the IC to be influential to reset the IC work. This pin is connected to a PNP-type transistor gate, so the transistor will be active if given a logic low. Normally this pin is connected directly to Vcc to prevent reset
• control voltage, this pin serves to regulate the stability of the reference voltage negative input (comparator A). This pin can be left hanging, but to ensure the stability of the reference comparator A, usually associated with a capacitor of about 10nF to berorde pin groun
• threshold, this pin is connected to the positive input (comparator A) which will reset the RS flip-flop when the voltage on the capacitor from exceeding 2 / 3 Vc
• discharge, this pin is connected to an open collector transistor Q1 is connected to ground emitternya. Switching transistor serves to clamp the corresponding node to ground on the timing of certain
• vcc, pin it to receive a DC voltage supply. Usually will work optimally if given a 5-15V. the current supply can be seen in the datasheet, which is about 10-15mA.

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Simple circuit of elektronic buzzer

Gbr. Skema Rangkaian Elektronic buzzer

Simple Electronic buzzer series is a series that only use 2 resistor, 3 capacitor , NE555 Chip, switch, and speaker. string up series of simple electronic buzzer is also very easy and simple. IC NE555 is the frequency of 1 kHz when the switch is pressed. This frequency can be set using the potensiometer 10 KOhm. Picture a series of simple electronic buzzer can be seen above:


IC NE555

555 timer IC provides practical solutions and relatively inexpensive for a variety of electronic applications related to the timing (timing). Especially two of the most popular application is a series of monostable and astable timing.

• Pin 1: Ground, is the input pin of the source of the negative DC voltage
• Pin 2: trigger, negative input from the lower comparators (comparator B) that maintain oscillation capacitor voltage in the lowest 1 / 3 Vcc and set RS flip-flop
• Pin 3: output, the output pin of the IC 555.
• Pin 4: reset, the pin that serves to reset the latch inside the IC to be influential to reset the IC work. This pin is connected to a PNP-type transistor gate, so the transistor will be active if given a logic low. Normally this pin is connected directly to Vcc to prevent reset
• Pin 5: control voltage, this pin serves to regulate the stability of the reference voltage negative input (comparator A). This pin can be left hanging, but to ensure the stability of the reference comparator A, usually associated with a capacitor of about 10nF to berorde pin groun
• Pin 6: threshold, this pin is connected to the positive input (comparator A) which will reset the RS flip-flop when the voltage on the capacitor from exceeding 2 / 3 Vc
• Pin 7: discharge, this pin is connected to an open collector transistor Q1 is connected to ground emitternya. Switching transistor serves to clamp the corresponding node to ground on the timing of certain
• Pin 8: vcc, pin it to receive a DC voltage supply. Usually will work optimally if given a 5-15V. the current supply can be seen in the datasheet, which is about 10-15mA.

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