Door Buzzer Systems | Electronic Project Circuits

Posts Tagged ‘door buzzer systems’

Fridge door Alarm

Beeps if you leave open the door over 20 seconds
3V battery operation, simple circuitry

This circuit, enclosed into 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, the photo resistor R2 presents a high resistance (>200K) thus clamping IC1 by holding pin 12 high. When a beam of light enters from the opening, or the fridge lamp illuminates, the photo resistor lowers its resistance (<2K), 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 fridge door closes. D2 connected to pin 6 of IC1 allows the piezo sounder beeping 3 times per second.

Parts:
R1____________10K 1/4W Resistor
R2___________Photo resistor (any type)
R3,R4________100K 1/4W Resistors
C1____________10nF 63V Polyester Capacitor
C2___________100µF 25V Electrolytic Capacitor
D1,D2_______1N4148 75V 150mA Diodes
IC1___________4060 14 stage ripple counter and oscillator IC
Q1___________BC337 45V 800mA NPN Transistor
BZ1__________Piezo sounder (incorporating 3KHz oscillator)
SW1__________Miniature SPST slide Switch
B1___________3V Battery (2 AA 1.5V Cells in series)

Read More Source : http://www.redcircuits.com/Page15.htm

Be the first to comment - What do you think? Posted by admin - February 17, 2011 at 8:42 am

Categories: Alarm systems, home alarm systems Tags: door buzzer systems, door stop alarm

Circuit Door Buzzer by NE555 + LM386

Someday I goes to visit a friend. He begs me helps to seek electric bell front door circuit. In model to be simple, use the a little equipment. I then choose the Door Buzzer circuit this give. Because of use , IC NE555 produce electric bell sound and use IC LM386 for amplify talk at one time. For R1 use fine decorate the sound as you like it. request have fun this circuit.

Be the first to comment - What do you think? Posted by admin - May 22, 2007 at 12:33 am

Categories: Audio diagram, Circuit diagram Tags: buzzer sound, door buzzer systems

Door buzzer with 555

This is easy circuit buzzer. It use IC 555, Speaker 25 -80 OHM.

I demolishes a store-room , see old loudspeaker and other equipment a little again. Then born the though builds Door Buzzer by use , IC 555. Perform sound electric bell origin. When press S1 as a result have a voice fair loud. This circuit almost must not do anything. Because divisible Amen! should use 25-80ohm size loudspeakers. will make good sound use force against electricity low work or economize the electricity. You will may use 9V batteries all right sir.