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Topic: Seismograph (Read 7 times) previous topic - next topic

tkbyd

Thanks for the interesting comments... keep 'em coming!

Want to measure: As much as possible... i.e. the direction and amplitude of the pendulum's movement relative to basement.

Live in earthquake zone: They are rare and small, but do occur. Mostly a "can I do it?" exercise.

Geophone: I suspect the pendulum would be more sensitive, and less prone to pick up the effect of footsteps or big vehicles going by the house. Also: Doesn't give information on direction of movement.

Laser/ Amplitude... I guess I'm just a digital junkie.... No problems of compensation for accumulation of dust, etc. Sounds like a good sensing idea to implement alongside the digital "answer", to see how they corespond.

Optical mouse.... interesting idea! Might be hard to position mouse close enough to reliably "read" target on bottom of pendulum... but probably not impossible. Avoids need to feed power across the pendulum's suspension. I wonder what the resolution/ response time trade offs would look like. Main dis-incentive: I don't wan't to deal with talking across the mouse's USB interface.

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Further new idea, prompted by the laser suggestion....

If two small mirrors were mounted at 90 deg to each other on outside of pendulum, at an to vertical, and each had a vertical beam of light bounce off it, the "spot" thrown off would move up and down the wall it hit. Two simple linear arrays of light detectors (probably something like the sensor in a scanner?) could determine the pendulum's position. Anyone know of the sort of sensor this would entail? One of the beauties of this solution is that by varying the angle the mirror was mounted at, you could change the sensitivity and range of the instrument.

robtillaart

idea:
you could place a horizontal line laser near the pendulum so a shadow is cast on the wall with sensitive detectors. If the laser is placed near the pendulum there is an angular magnification (I don't know how to call it otherwise).  A slight movement of the pendulum gives a larger displacement on the wall. It is easy if the pendulum is a cilinder to detect X and Y movements. Then one can calculate in which direction the cilinder moves first, and this might be indicative for the direction of the epicentre.

idea ?
I can imagine a sphere floating in a magnetic field as pendulum. Then 3 dimensions might be possible?
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

WillR


idea:
you could place a horizontal line laser near the pendulum so a shadow is cast on the wall with sensitive detectors. If the laser is placed near the pendulum there is an angular magnification (I don't know how to call it otherwise).  A slight movement of the pendulum gives a larger displacement on the wall. It is easy if the pendulum is a cilinder to detect X and Y movements. Then one can calculate in which direction the cilinder moves first, and this might be indicative for the direction of the epicentre.

idea ?
I can imagine a sphere floating in a magnetic field as pendulum. Then 3 dimensions might be possible?


Rob:

I think that idea might go to he11 in a hand basket if there is too much motion in three dimensions. You can't even be sure that the wall be there to hold the sensors in a large quake...  ]:)

Imaginative though...

Just another Hacker

robtillaart

Quote
You can't even be sure that the wall be there to hold the sensors in a large quake... 

If the quake is that large you don't wait for the Arduino to tell you there's a quake ...

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

WillR


Quote
You can't even be sure that the wall be there to hold the sensors in a large quake... 

If the quake is that large you don't wait for the Arduino to tell you there's a quake ...





Good point! INCOMING!!!!
Just another Hacker

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