The article shows an earthquake sensor circuit idea which incorporates an innovative way of detecting the minutest of shocks caused by a possible earthquake tremor. The circuit is so sensitive that it is able to detect tremor of 4 on the Richter scale, yet remains unaffected to loud sounds or irrelevant bangs or noises.
Introduction
I have seen a number of different circuits of seismic sensors on the net, however most of these have utilized a piezo transducer as the sensor element, God knows how a piezo would detect earthquake tremors.
It simply appears absurd because a piezo transducer would be solely able to sense high frequency vibrations and never a swaying action.
An earthquake will never generate a shrill noise rather it produces a gentle swaying pattern, when it hits.
Therefore using a piezo element is a flop idea, according to me.
Of course a piezo would detect tremors only if it were used in the form of a load-cell, by integrating some kind of load, assembled for implementing an oscillating action during tremors.
In the present earthquake sensor circuit, I have used water as the detecting agent.
After some experimentation I found that water is an excellent sensor of vibrations as well as a swaying kind of motions.
You can test waters behavior by keeping a bowl of water on the table and giving a gentle knock on the table.
Even the slightest of legit vibration is enough to create a nice ripples on the surface of the water.
I could have used an LED/LDR arrangement for detecting these ripples, however since we are not interested in sensing vibrations rather only swaying actions, I made a little out of the way approach.
Through a few of my previous posts I have already discussed water level sensor circuits where the water's conducting property is well exploited for the purpose.
The same property has been harnessed for getting the intended results.
How the Earthquake Sensor is Designed to Operate
Looking at the circuit diagram we see that the configuration in fact has nothing serious.
The electronic part consists of a couple of transistors rigged into a latch circuit.
The input to this circuit is achieved from a small half round container filled with water.
The positive supply from the circuit is dipped inside the water while the hot end of the input is placed in such a way that it stands just a mm above the water.
During a possible earthquake (God Forbid) the water responds to the tremor and starts generating a swaying movement.
The moment the water moves, its level gets disturbed and connects the hot end of the circuit with the positive terminal, dipped inside the water..
The positive of the supply immersed in the water instantly makes contact with the HOT end of the circuit via the water, the circuit gets triggered and immediately latches.
The connected buzzer sounds, sending an alarm signal.
The container can be made by cutting a small children plastic ball into half.
After doing the required settings inside this half cut ball, it may be filled with water as shown in the diagram and sealed.
The container then should be fixed somewhere such that the level off water inside the ball retains perfectly horizontal position without any deviations.
Deep says
I have got an electrolytic capacitor…. Which end of it should be connected to the transistor?
Swag says
positive lead will connect with the positive line, negative to the transistor
Deep says
Sir is the capacitor used in the circuit a ceramic capacitor or any other type?
Swag says
Deep, it can be any type, polar or non-polar, ceramic whatever you can get.
Unknown says
Hi, iam a mechanical engineer iam working on a hydroponic farm project now and I need some help on a timer circuit can you please help me out I need yor email id so that i can share my project setup with
Swagatam says
Hi, my email is in the contact page, or you can also find it at the top portion of the sidebar.
Gomnic Asuncion says
sir can I ask what is the radius of the sound that the buzzer can make? at least what approximately 1 room or what? thank you
Swagatam says
Gomnic, you can replace BC557 with a TIP127 transistor and use a high power car siren in place of the buzzer, that would upgrade the sound to a huge level.
the shown buzzer will be able to alert only around the area where it's installed
Gomnic Asuncion says
sir once the water touch the hot wire and the circuit was closed.. will the buzzer continuously alarm even the hot end don't touch the water anymore?
Swagatam says
the buzzer will latch and sound continuously until the power is switched OFF and ON again
Susan says
what shud be the specification of buzzer
Swagatam says
it can be a 12V piezo buzzer….
Kwizera Yannick says
hello sir i want to ask if is possible you can tell me where i can found the working principle of the circuit please answer me
Swagatam says
hello Kwizera, the working principle is explained in the article itself.
Swagatam says
for biasing the transistors so that they can turn ON
Swagatam says
….sorry that was for R1/R2….T1 and T2 are connected such that they latch up when triggered.
Kwizera Yannick says
sir what's meaning of latches bcz you have said cap will prevent the latches and R100 latches the ckt plz tell me and T1andT2 will latch up what it mean
Swagatam says
why did you delete the earlier comment?
cap will prevent accidental switch ON latching of the circuit….but when actual earthquake ir detected the circuit will latch through the 100k resistor and T1/T2 combination
Kwizera Yannick says
sorry sir i was thinking that my comment is no more needed but i will never delete it again but sir did you mean that T1 and T2 will work as suitch
Kwizera Yannick says
sir is any problem when i say that 100k will work as feedback
Swagatam says
T1 and T2 are configured to switch ON and latch when the input is triggered via the water movement.
the 100k is the feedback link which initiates and sustains the latching effect
Kwizera Yannick says
hello sir i want to ask if this circuit can measure the strong of an earthquake bcz you have said it in the introduction that is so sensitive to detect tremor on 4 Richter scale and i have seen that Richter scale is measure of strong of an earthquake and if it can detect tremor before people hear it plz tell me.
Swagatam says
hello Kwizera,
the circuit is designed to detect and sound an alarm, it will not measure the level of the earthquake…and it cannot detect tremors before it actually takes place
Kwizera Yannick says
then sir in which distance it can detect the tremor? and if it can detect it before someone who is close to the ckt hear it
Swagatam says
as soon as the building experiences a slightest bit of movement due to the tremor, this circuit will activate and sound the alarm.
Kwizera Yannick says
hello sir, i want to ask what did you mean Richter scale because i found that it is the measure of strength of an earthquake but earlier comment you told me that it cannot measure but it will detect then tell me how it can detect detect on 4Richter scale? thank you.
Swagatam says
Hello kwizera, it will not measure, it will only get triggered at approximately 4 Richter scale
as soon as there's a slight tremor detected, it will sound a alarm.
Anonymous says
hello.sir i want to ask if this circuit will give us signal when earthquake is happening or before it happen and i want to know the application of that capacitor
Swagatam says
hello, the circuit will sound an alarm as soon as the house begins trembling.
nothing has been invented in this world so far that has the capability of producing a prior warning indication.
Anonymous says
hi, what if Bc557 is not available? can i replace it with other transistor?
Allen Wang says
Yes, You Can Replace Your Bc557 With Other Transistor And You'll Figure It Out By Yourself And If Any Trouble You Can Always Reach
Me By Contacting Through Email? Thanks, Man You're The Best!
Sanjeev Tyagi says
I am confused about your other circuit "Cheap Semi Automatic, Tank Water Over Flow Controller Circuit". In that circuit has no positive supply at the collector of Darlington pair. Kindly clear it for me.
Swagatam says
T1/T2 are kept for grounding the base of T3 when the water level reaches the top of the tank, here the base voltage of T3 becomes the positive for the Darlington.
Sanjeev Tyagi says
I am using this circuit after some modification as water level cum pump controller circuit. But unable to upload modified circuit.
Swagatam says
you can send it to hitman2008@live.in
Sanjeev Tyagi says
circuit is sent to hitman2008@live.in . power supply for motor is used when relay is inactive and when relay activated power supply of motor stopped. means when water touches touch point relay activated and power of motor is stopped.
Swagatam says
thanks, I got it, it's a very simple and useful design for controlling water over flow in tanks.
Susan says
can i get this circuit sir…my email is susanlama12@gmail.com…plz email me the design
Anonymous says
hi i tried this circuit ,but the buzzer sound occurs even if the contact points to be placed in the water are placed in air
Swagatam says
use 33uF or above for C1.
gaurav maneral says
Sir how can i test this project. I have made this And want to know how wii it work.
Swagatam says
ruffle the water level manually so that it bridges the given contacts, this action should activate the alarm and keep it sounding until the power is switched OFF. This will confirm its operation.
Allen Wang says
Well. Did You Try To Shake This Up With A Table And It Might Work
Unless You Have A Right Tool For Your Earthquake Project? Right,
Maneral? Good? Thanks For Your Nice Post!
Anonymous says
Will this circuit work with 12 V battery ?
Swagatam says
yes it will work
Allen Wang says
Yes, Anonymous If You Have The Right Tool For Your Earthquake
Project You Can Use 12 V Battery?
Valencia says
if i want to put switch so the buzzer will stop ringing, where should i put that ? i made this one and if it detects tremor then the buzzer will ringing continuously right ? i want to put switch where if it detects tremor then when i open the circuit by the switch then when i close again the circuit by the switch the buzzer wil stop ringing. if i want to make it that way, where i should put the switch ? thank you in advance~
Swagatam says
you can put the switch in series with the 100K resistor, it will do the required function.
erin says
Sir, I made this circuit but my buzzer is on even though it's still an open circuit. i made it correctly following your picture. do you know what's wrong? my friend said it because of the transistor 557. please help me.
Swagatam says
Hi Erin,
Make C1 = 10uF and add a 1K resistor across it, this will rectify the issue.
erin (erin.coklat@hotmail.com) says
thankyouuu vry much for your help 🙂 i made a mistake in connecting the pnp transistor. so i use the same circuit as you and add LED as the output. if i may ask, if there's an earthquake, the buzzer will still on right until we cut the source? could you explain what is happening? is it because of the capacitor become the source ? or anything else? and if i may know why did you chose those resistors? thank you in advance:D
Swagatam says
the 100k resistor latches the circuit when it detects a tremor, that is when the water level shorts the sensor points. this locks the circuit and the buzzer keeps sounding continuously.
Anonymous says
Hi sir, can I ask what is the function of capacitor here? if i want to add LED as an output how big the resistance should i use ?
Swagatam says
the capacitor prevents the circuit from latching when switched ON.
use a 1k resistor for an LED
Kevin Venasquez says
Thankyou for this circuit.Finally we've make it work! Godbless!
Swagatam says
you are welcome!
Allen Wang says
Aw, That's Of Sweet Of You? Thank You, Mr. Kevin! God Will Bless Y
ou No What Matter What Happens He's Always There For You Whate
ver You Need Him Just Fear Him And Pray To Him And Confess!
PS God Will Never Let You Perish In A Storm or Disaster And Alw
ays Faithful And Good In Hard Times And Trouble Coming You
r Way In Life!
Charlene Rivas says
Hi. May I ask what IC number may be used for this circuit? I'm not an EE or ECE student, but we have to make one of these for our class. Your help will be very much appreciated.
Anonymous says
Hello sir, may we know what part number is the IC you used here?we are planning to do it in your account.thanks.
Kevin Venasquez says
Hello sir, may we ask what is the part number of the IC? yours is a good idea to make,hence it is simple to understand. THANKS!
Swagatam says
Hi Kevin, where's the IC??? I can't see any.
Anonymous says
hi sir,
what is the 'hot end of the circuit' mentioned above? Is it the other end of 1K resistor?
Swagatam says
yes that's right!