Seismometers for Schools and Others on a Budget!

Jacob’s Adventure

Jacob, Age 12
Feb. 25, 2012

Builds a Seismometer

 


 

Jacob, a 6th grader with a vision and a mission, from Lowell Scott Middle School, in Meridian, Idaho, sets out on an adventure to build a

SLINKY VIII

Seismometer and then record earthquakes near and far, from

around the world.


Can a man of limited years pull this off?

Boise State University, Dr. Van Wijk, Mr. Channel, and Jacob’s Mom think so,

and so does Jacob!

 

Chapter 1

An Overview

Jacob will need a computer with special software.

His teacher, Mr. Rosato, will provide that, with guidance from BSU.

His friend, Mr. Channel, will provide plans, encouragement, and hand him tools.

Jacob will need an amplifier that he will build from a “NERdaq Parts Kit.”

Jacob will need a seismic sensor. He will build it from a box of parts, called “Slinky Seismometer Parts Kit” provided by BSU.

He could have obtained it fully assembled, but Jacob wants to build it himself.

When it is finished, it should look something like this:


 

 

 

 

 

Chapter 2

The Amplifier

This very important part will amplify the faint electrical signal coming from the sensor’s coil. Like the sensor, the amplifier will be made from many small parts—electronic components soldered onto a printed circuit board.

Here are the electronic components:

 

 

 

Here is Jacob beginning the process of building the “NERdaq” amplifier.


He has a schematic, which is like a map or a set of directions showing where all the parts go. All the parts are in bags with their names and numbers on them.


 

 

This is a more technical view; Jacob will not need to understand all this, but simply place C5 through the holes in the board, marked C5. Really easy!


 


 

 


 

Here he is placing C5 (capacitor #5) into the holes on the board marked “C5”; R3 (resistor #3) into the holes on the board marked “R3,” and so on.


 

He will continue this process until all the parts have been inserted and soldered into place.

Here he is clipping off the excess wires from some of the components.


The finished printed circuit board attaches to the Arduino Uno, to complete the amplifier.

 


 

 

 

When he is finished, the amplifier will looks like this.

 

 


 

 

 

 

 

 

 

 

 

 

Chapter 3

The Slinky VIII Seismic Sensor

Jacob opens the box and finds all these parts, plus an installation assembly sheet.

 

 


 

 


 

He begins by assembling the 5″ eyebolt and three magnets.

 

 


 

 

 

 

 

First, two magnets go onto the eyebolt, and then one nut.

 

 

 

 

 

 

Next, the second nut, followed by the third magnet. All three magnets are stacked North-South, North-South, North-South. Now he assembles the top ABS cap.


 

 

The 4″ eyebolt and one nut go into the hole in the cap.

He flips the cap over, adds the second nut, and then one plate.

 

 

 

 

 

He inserts the second plate into the slinky spring, leaving about 17 coils below the plate. He inserts these over the 4″ eyebolt and secures them with a nut, finger-tight.

This forms a sandwich to retain some of the spring between the two plates, and some coils free to stretch. If more or less spring length is needed, he can change how many coils are below the plate.


 


He joins the Magnet assembly to the ABS cap by looping the eyebolt over the end of the spring.


 

 

 

 

The Base assembly:



 

 

As illustrated…………………..He attaches all three legs.

 


 

He flips the base over and adds all three feet……3″ eyebolts.


Assembling the Acrylic tube:

He inserts the RCA cable, from the outside into the smallest hole in the tube. The larger 6 holes are for screws. He pulls the bare ends of the wire out the bottom of the tube.


He attaches the coil to the two leads…..it does not matter which wire goes where, and finger-tightens both wires between the first and second nuts on the coil.



He inserts the coil and attaches the cable, from the bottom of the tube, up to the top three holes.


He inserts three brass screws through the holes and threads them into the larger white ring of the coil, three or four full turns are enough. Jacob makes sure to not thread the screws so far that they are visible on the inside of the white ring.

 

The large white ring of the coil faces down as shown:



 

He turns the tube so he can see down the center and positions the coil to the very center of the tube, like a Bulls Eye, then finger-tightens all three nuts to hold it in the center.


He repeats this process for the copper damper tube.

Adding three brass screws, he centers the copper tube and finger-tightens the three nuts.


Again, he makes sure not to thread these screws too deep into the copper, about one or two rotations is enough.

 

Looking down the tube again, he makes sure both the coil and the copper damper are centered in the acrylic tube.


 

Jacob now inserts the acrylic tube assembly into the base assembly and adds the small plastic clip to the base to secure the RCA cable.


Now he lowers the ABS cap with spring and magnets into the top of the acrylic tube.



 

The top two magnets need to be centered in the coil and not touching the walls.

The same for the bottom magnet, centered in the copper damper tube.

 

 


 

Jacob achieves centering, as seen from above, by adjusting the three legs, and when all the magnets are perfectly centered, the nuts on the legs can be finger-tightened.


The top of the two coil magnets, as seen from the side, need to be even with the top of the coil. This can be done by adding or subtracting coils of spring.

He can also turn the nut on the top cap, raising or lowering the entire spring/magnet assembly and, lastly, the magnets can be independently raised or lowered by threading them up or down the magnet eyebolt threads.

The damper magnet needs to be about even with the top of the copper damper tube.

Now he plugs the sensor into the amplifier, and the amplifier into the computer via the USB cable.

Jacob has just finished his Slinky VIII Seismic Sensor….

 

 

 

 

 

Once the USB is plugged into the computer containing the software,

AmaSeis, Winquake, and Arduino, and some drivers loaded,

Jacob sees his first signal, but it is just noise from footsteps.


However, later that night, an Earthquake: 6.8M in Siberia, Russia


Mr. Channel spoke with Jacob before, during, and after the building of this seismometer, and asked these questions:

1. Do you think you can assemble the NERdaq amplifier?

J: Yes, I do.

2. Have you ever used a soldering iron before?

J: Yes, I have when I did stained glass.

3. Do you think you can assemble the Slinky VIII sensor?

J: I’m a little nervous but I think I can do it.

4. After you finished, what was the easiest part?

J: It was building the base.

5. After you finished, what was the hardest part?

J: There wasn’t a hard part.

6. What changes to the “Slinky Seismometer Parts Kit” or instructions would you suggest?

J: I wouldn’t change anything.

7. Would your experience, doing the assembly, be helpful in training other students to build theirs?

J: Yes, I would be able to point them in the right direction.

8. How long did it take you to build the NERdaq amplifier?

J: It took about 15 to 20 min.

9. How long did it take you to build the Slinky VIII?

J: About 10 to 15 min.

 

10. What do you expect the seismometer to do?

J: Read the vibrations in the ground.

11. Who would you contact for questions about your new seismometer?

J: Mr. Channel
tchannel@cableone.net

12. Was it fun?

J: Definitely!

 

A few comments from Jacob to the readers:

I thought it was cool to set up the amplifier with the computer and tap on top of the Slinky VIII and watch the reader.

I touched the soldering iron to my finger and it dried out the skin there. It only stung a little.

I think my teacher should take the seismometer and use it in the future.

Jacob M.

 

 

 

 

 

 

 

 

BSU, Boise State University, Dr. Kasper Van Wijk, ssis@cgiss.boisestate.edu

His helper, Mr. Channel, tchannel@cableone.net 208-286-4787

 

Visit: http://cgiss.boisestate.edu/~kasper/geoph297wiki/index.php/BSU_Network

 

Here is a BSU site which tells where to get the software:

http://cgiss.boisestate.edu/~kasper/geoph297wiki/index.php/Home-built_Seismometer_Hardware_and_Software

 

Here are additional instructions:

http://cgiss.boisestate.edu/~kasper/geoph297wiki/index.php/

Slinky_Seismometer_Sensor_Assembly_Instructions


 

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