Can You Make DIY Magnetometers?

Short answer: yes, but unless you are a trained electrical engineer, the odds of making a magnetometer useful enough for geological surveys are very low. If you need a land survey, hire a professional instead!

Amateur scientists, on the other hand, might still want to build a fluxgate magnetometer in order to track solar flares or gain a general idea of the magnetic characteristics of your home city. Building one requires common materials and tools, but uncommon expertise.

Can You Make DIY Magnetometers?

Materials List

– Copper wire
– Wire cutters/strippers
-Cardboard box
– Resistors
– Two commercial or homemade capacitors, of around 0.5 microfarads
– 12 volt DC power supply
–  USB
– A sound card
– Headphone connector
– Linux laptop

Basics

A fluxgate magnetometer uses two coils on different circuits: the “drive coil” and the “sensor coil.” The drive coil is a symmetrical ring with the coil wrapped around it, so that the magnetism produced by one half of the coil is mostly cancelled by the other half. It will not be possible to achieve complete symmetry and thus complete cancellation without a machine, but “close enough” is good enough. Use a capacitor to even out fluctuations in current. This circuit is hooked up to the DC power supply to create a continuous magnetic field. If you test the current on this coil, it should be a predictable sine wave.

The sensor coil can be a wire curled around a cardboard box. This box should be large enough to enclose the drive coil, but not much larger. This coil is also connected to the power supply at a higher resistance and with a capacitor. It should also be wired to a headphone connector. When you plug the connector into a sound card, it should produce a predictable pattern of sound. Any Linux application that graphs sound inputs can then be used to create a baseline graph of how the circuit performs without the drive coil. When you put the drive coil in, it should create a more erratic graph that shows slight changes in the Earth’s magnetic field in the direction that the drive coil is facing. By taking this apparatus around your city, you can see how the magnetic field changes depending on location. Particularly strong magnetic vectors appear above mineral deposits.

Advanced

If you know enough about electric engineering to still be with us, then you also know that these directions are not detailed enough. There’s a good reason for that: the specific resistors, placement of resistors, and circuitry will depend greatly on your materials and needs. If you build your own fluxgate magnetometer, take the time to truly understand the theoretical basis of how they work and read up on similar DIY projects. Your magnetometer will likely end up needing some unique touches to work, so don’t be afraid to experiment!

All that said, if you only want a magnetometer to survey your land, it is far more reliable and time-effective to hire a geologist with a proper magnetometer to do it for you.

Author Bio

Daniel Walker is a young journalist portraying his efficiency in a well known Canadian journal. Apart from the fields of politics and media, motorsports attracts him. So he finds his leisure time researching and blogging about new vehicle technologies. He says his father, Dr. Edward Walker as his inspiration who has taken a PhD in Automobile Engineering.

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