This device may not work. Then again, it might. But until it is tested thoroughly, we will not know if it works or how well it works. My hope is that several of these can be built and installed in several cities across the country. Then, when an earthquake occurs in one of those cities, we will know if this device will work properly or not work at all. If it does work, then a history of various earthquakes will have to be collected in order to be able to accurately predict the time and severity of an upcoming earthquake. This method of predicting earthquakes is based on the following facts.

1. Contrary to what scientists teach, earthquakes ARE predictable. In every case, animals have behaved abnormally for hours to days before an earthquake. In Kobo, Japan, the zoo animals were acting so strange that the zoo keepers took it as an omen that something terrible was about to happen. In other cases, dogs have barked wildly, or pets have simply run away in mass. Scientists attribute this behavior of animals to what they call "micro tremors." These are believed to be earthquake tremors so small no instrument can measure them, but somehow animals can still detect them.

2. Animals are sensitive to, and can even navigate by, magnetic fields. Stories of long lost animals finding their way home abound. Cats and dogs have found their way back home from thousands of miles away, sometimes from the other side of the country. In an attempt to understand this ability of animals to find their way, scientists studied sea turtles. They can return to the same beach where they were born 30 years later. How do they find that beach? Scientists discovered that baby sea turtles, when placed in a pool, swam exactly East to West. When a magnetic is placed by the pool, they swim around the magnetic field of the magnet. It is a little known fact that magnetic fields are strongest at the North and South poles and weakest at the equator. If you can sense the strength and direction of magnetic fields, you can navigate by them. (The information on animal navigation is from a PBS special.)

3. Magnetic abnormalities exist around fault lines and the edges of tectonic plates. These are believed to be 'fixed" and thought to not change. Scientists attribute them to iron ore that settled when the North to South magnetic field was pointed in a different direction, or before the tectonic plate rotated from its original axis.

My belief is that they are caused by rocks like quartz that produce electricity when put under pressure. This electricity, when it flows through minerals and water, produces a magnetic field. This field aligns iron ore, etc., to match the abnormal field. Quartz only produces a brief current when the pressure on it changes so it might appear as pulses of abnormal magnetic fields. That would explain the confusion of animals if they navigate magnetically.

OPERATION

To operate, the sensor is pointed North, then rotated from down to East to up to West.

A stepper motor performs the operation of rotating the sensor and stops several times along the way for the computer to record the field strength. The stepper motor is from an old 5-1/4 inch floppy drive'

The magnetic field sensor is glued on one end of a three-inch piece of plastic. The other end is screwed into the wheel on the stepper motor's shaft. The sensor is powered from positive and negative five volts so that if there is no magnetic field, the output will be close to zero volts. The regulators must be fairly accurate so the output will stay close to zero volts.

Magnetic field strength is measured using a 12-bit analog-to-digital converter. The converter has a range of positive to negative five volts, so it can measure any field the sensor can detect. The sensor is 25 millivolt per Gauss or .025 volts per Gauss. If 2048 is 5 volts and -2048 is -5 volts, then the smallest measurable voltage is 5V/2048 or .0025 volts. If my math is correct, that would then correspond to a field of .1 Gauss.

An optical switch from the track zero stop of an old 5-1/4 inch floppy disk drive is used to sense when the sensor is pointed down. A nail is glued into the slot on the back side of the stepper pointed so that it interrupts the optical switch when the sensor is pointed down.

The program always starts by rotating the sensor and looking for a signal from the optical switch to say that the sensor is in the down position. It then takes a sample of the field strength. Since we are collecting 12 bits, four bits at a time, this will take three, four-bit inputs to get all 12 bits of data. The result is then checked to see if it is a new minimum or maximum field strength and, if it is, it is stored for future reference. After two samples at each position, the sensor is then rotated back for two more samples at each position.

Once a pass is completed, the sensor is parked in the up position, and the final results are tallied and displayed. The difference between the minimum and maximum from each pass is displayed and the average of the four passes is computed. Even then, I run three or four cycles because the results vary with each cycle. Eventually, I hope to add software to automatically run the program every hour for 24 cycles a clay.

The software is available for downloading at my web site located at http://www.elim.edu/tech. The magnetic field mapping device program listing is in Quick Basic.

CONSTRUCTION

Everything is mounted on a piece of plastic about 12 inches by four inches in size. I used some surplus red plastic, but any insulating material would suffice. The stepper motor is mounted with the bracket that held it into the disk drive. Some one-inch metal spacers are used to mount it up higher. The circuit board is mounted with similar spacers. The stop sensor on the back of the stepper motor is glued on.

The magnetic field sensor is a Hall-Effect sensor made by Micro Switch. It is available from Newark Electronics for about $15.00 each. The part number is SS94AIF;., ..-chosen for its higher sensitivity of 25 rnV/Gauss. The Hall-Effect sensor is glued onto the end of the plastic piece of wire mold with the components facing up. The pin connections are from left to right, positive power, output, and negative power. An extra long wire is used to allow room for it to rotate freely.

The power supply is an AC adapter with positive and negative 12 volts outputs. I cut off the connector that came with the adapter and used a binding post to connect it to the circuit board.

A 26-pin header connector is used to connect a ribbon cable about two foot long to a 25-pin male connector that plugs into the printer poFt of a laptop computer. A desktop computer may not work as well as it will generate magnetic fields that might interfere with the operation of the detector. A solution there might be to use a fivefoot, 25-pin extension cable.

Not shown on the schematic, but very necessary for proper operation, are filter capacitors on the inputs and outputs of the voltage regulators. Also filter capacitors are needed on the ICs, especially on the MAXI22 analog-to-digital converter's power and ground pins. NV

schematics