Instructables
Picture of Earthquake Detector
I grew up in California, and have had the fortune of experiencing every major earthquake in this state since I was born. I love them and fear them at the same time! Earthquakes are exciting, but also mysterious. Living in such a seismically active state, there are earthquakes all the time that most people don't even feel! That is why I decided to build this Earthquake Detector



 
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Step 1: Tools and Materials

Picture of Tools and Materials
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(x2) 741 OpAmps (Radioshack Catalog #: 276-007)
(x1) 9V Relay (Radioshack Catalog #: 275-005)
(xvar) jumper wires (Radioshack Catalog #: 276-102)
(x2) Heavy duty 9V battery clips (Radioshack Catalog #: 270-324)
(x2) 9V batteries (Radioshack Catalog #: 23-866)
(x1) Prototyping PCB (Radioshack Catalog #: 276-170)
(x1) Piezo Buzzer (Radioshack Catalog #: 273-080)
(x1) 5K Ohm Potentiometer (Radioshack Catalog #: 271-1714)
(x1) Potentiometer cap (Radioshack Catalog #: 274-415)
(x1) 470 Ohm Resistor (Radioshack Catalog #: 271-1317)
(x1) 3" diameter acrylic tube
(x1) Magnet (Radioshack Catalog #: 64-1888)
(xvar) lamp-pull ball-chain


Tools:
Solder
Soldering Iron
Wire Snips
Hot Glue Gun

I used a laser cutter to make my own personal enclosure, but one could easily modify a pre-made project enclosure to suit the needs of this project.

Step 2: Modify the 9V relay

Picture of Modify the 9V relay
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The only part needed from the 9v Relay is the magnet coil, the rest of the pins are not needed.

I trimmed all of the leads off of the relay except the ones that attach to both ends of the coil. I then soldered wires from each of the leads from the coil.

The purpose of the magnet coil in this circuit is to detect when the hanging magnet from the cylinder passes over it. The magnet sways when the earth moves, triggering the piezo buzzer to sound, and the LED to illuminate.

thanks :) it works now.

thanks :) it works now.

thanks :) it works now.

thanks :) it works now.

Hi nice project. What if I use 6V relay.? what will happen? PLEASE REPLY. I copy your project.

audreyobscura (author)  john.bobadilla.710 days ago
should still work.

Hi nice project. What if I use 6V relay.? what will happen? PLEASE REPLY. I copy your project.

Elenapervez11 months ago
how can we add a sound alarm to it? PLEASE REPLY.i need to make this urgently!!
David971 year ago
I live in Christchurch, New Zealand. I wonder how sensitave this would be as we have just had an earthquake that caused us to loose water for 2 weeks and power for a month and killed 300. We are still getting aftershocks a day after 2 years!
nice work!
Attmos2 years ago
Every home in California should have one. ;)
static2 years ago
While not exactly the sme Forest Mimms II had a similar project in Science Probe. Simply used a wound coil, and had mineral oil to dampen the magnet movement. Also had an output that could go to a chart recorder or PC recorder software
Light_Lab2 years ago
If you want to focus on earthquake motions you probably want to detect the vertically moving primary waves. These have a frequency around 0.1 to 1 Hz.
http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/seismometers.html
The easiest way to do this is to have a fairly heavy weight on the end of a coil spring. This will increase the sensitivity to lower frequencies. The other thing to do is to have some sort of damper like a paddle in oil. This might reduce non-earthquake vibration detection like trucks and people walking around.
You could do some of this electronically with filters.
pfred22 years ago
We had an earthquake here last year. It sucked! When the Earth is moving there really isn't anything anyone can do about it now is there? It was really more like a wave here. I saw my garage floor come up, then sine wave fashion go back down again. I thought I was flipping out. I mean we're not known for having earthquakes in these parts. In any event the feeling of helplessness I felt was palpable. I like my terra firma!
audreyobscura (author)  pfred22 years ago
Agreed. I have been on the west coast my whole life, and have grown accustomed to earthquakes, I have noticed that my best earthquake detector is my dog - she goes and sits in my closet maybe 20 minutes before there is one.
couldnt you use a reed switch instead?
ppsailor2 years ago
Hi!
Years ago I built a motion sensor similar to the samples we.
Can you please show the circuit diagram clearer? FULL
To compare it with mine
THANKS
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audreyobscura (author)  ppsailor2 years ago
Circuit Diagram is now the main image for step 4.
ferjanyen2 years ago
Hi, a very nice project!!! I live in Spain, Torrevieja,(an earthquake aerea) and I would live to make this project but I would also like to see the circuit diagram for this project,
audreyobscura (author)  ferjanyen2 years ago
Circuit Diagram is now the main image for step 4.
devalpha_12 years ago
Great Idea. Kindly provide the circuit diagram.
audreyobscura (author)  devalpha_12 years ago
Circuit Diagram is now the main image for step 4.
TechGnostic2 years ago
My first Earthquake experience was when I soaking was in the tub. I hope that image doesn't violate the "be nice" policy : ))

Anyway, I was just lounging and enjoying the feel of the water when I noticed the water started to slowly sway side to side! I wasn't moving at all, and I couldn't understand what was going on at first. Since I live in a tectonically "stable" part of the planet, it took a few seconds to hit me that it was an Earthquake - a very mild one.

Since then I've always wanted to build a detector / data collector.

Not sure if you have this already - here's a link the the USGS Earthquakes data pages

http://earthquake.usgs.gov/earthquakes/


Thanks for some ideas on How-To.
AtomRat2 years ago
It's still great, can b used 4 many other things too! Ill still make one
AtomRat2 years ago
I have seen a different version of these where you can use the piezo buzzer as a mic to pick up the tremors, if you are interested, tell me and I'll find it for you, its an ebook ( like a '..For The Evil Genius' ebook collection. ) In the meantime, this one is much more simple, and I'll give it a go as I do need one at the moment for tremors that I swear can continue for days.

Is this kind of just a motion sensor 'switch', rather than a detector? Can you get a reading from this to log the strength of a quake / tremor, or is the relay just turning on an earthquake alarm for nearby people.
audreyobscura (author)  AtomRat2 years ago
It is more of an alarm. As long as the magnet is sweeping over the relay (triggered by the earth's motion), the buzzer will sound.