Introduction: Earthquake/knock Alarm

this inexpensive project can be used as knock/vibration activated alarm.If you are outside India,look at the parts list given below.
RESISTORS                                                             CAPACITORS                          OTHER PARTS
R1=680Ω                                                            C1=22µF/25V                                 D1,D2=IN4148
R2=120Ω                                                            C2,C5=[104]100KPF                     LD1=LED[5mm]
R3=220KΩ                                                          C3,C4=100µF/25V                        Q1=BC557B
R4=22KΩ                                                            C6=[102]1KPF                                Q2,Q3,Q4,Q5=BC547B
R5,R8=1KΩ                                                                                                                   Q6=BC549
R6=2.7KΩ[2700Ω]                                                                                                        B1=Continuous 3-24Vdc buzzer
R7=100KΩ                                                                                                                     PIEZO=35mm 2 C/O piezoelectric sensor
R9,R12=4.7KΩ[4700Ω]                                                                                               a 9V snapper
R10=10KΩ
R11=270KΩ
R13=1MΩ
you have to design your own pcb for this project.
the kit costs only Rs 77.
I bought the kit from my electronics teacher.
see the piezoelectric sensor.its a metallic disk

Step 1: Determining Color Code of Resistors

first and second band                         third band[multiplient]
0-black -------------------------------------------- 1                     
1-brown ------------------------------------------ 10=10^1
2-red ----------------------------------------------100=10^2
3-orange ----------------------------------------1000=10^3
4-yellow ----------------------------------------10,000=10^4
5-green---------------------------------------- 100,000=10^5
6-blue------------------------------------------1,000,000=10^6
7-violet----------------------------------------10,000,000=10^7
8-grey                                                       gold=0.1
9-white                                                     silver=0.01

Step 2: Put It Together-resistors

can you see the resistors?the resistors doesn't have any polarity.so it can be mounted in any direction.

Step 3: Put It Together-capacitors

capacitors C1,C3 and C4 have polarity.the white strip on the capacitor represents its -ve.others are disk capacitors so they can be soldered in any direction.

Step 4: Put It Together-diodes

the two geranium diodes have a black strip on one side.it is the cathode.

Step 5: Put It Together-LED

the led is also a diode.so it also have polarities.but how to find the polarities?there are no strips or colors.but there is a marking on an led.there is a flat portion on the led.you can see it when you are viewing the upside part.

Step 6: Put It Together-transistors

do it in order.look at the diagram of the transistor.

Step 7: Put It Together-piezo,snapper and Buzzer

piezo sensor has no polarity.so connect it as in the schematic.
connect the buzzer as shown in the schematic.
do the same for the snapper.

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