DIY Geophone Build Performs Well

March 2, 2024 by Lewin Day 14 Comments

If you want to know what’s going on with the ground, geologically speaking, a geophone is a great tool to have. It lets you listen in on the rumbles and grumbles beneath your feet, and can give you great insight into matters of seismic importance. [mircemk] has designed a very capable geophone that’s simple enough for you to build at home.

The geophone relies on a mass suspended upon a spring inside a chamber, which as you might imagine, will move when shaken by seismic vibrations. The mass is in fact a plastic rod, fitted with an iron nut and a magnet on the end.

This is mounted above a coil, which is fixed to the base of the chamber. Thus, when the chamber is shaken by seismic activity, the mass moves relative to the coil, with the coil picking up the varying magnetic field as it dances around.

The YouTube video does a great job of explaining the concepts involved and how to practically build the device. [mircemk] has also had some other great projects featured on Hackaday before, too.

Continue reading “DIY Geophone Build Performs Well” →

Scientists Call Out Apollo 17 After Investigating Moonquakes Past

September 19, 2023 by Lewin Day 35 Comments

In the vast realm of space exploration, new discoveries often emerge from old data. Thanks to advanced algorithms and keen observers, the seismic activities of our closest celestial neighbor, the Moon, have recently been thrust back into the limelight.

Thanks to the effort of the NASA crew involved in the Apollo 17 mission, it’s possible investigate these phenomena today with datasets from the past. Recently, researchers working with this data turned up some intriguing findings, and published them in a new paper. It reveals that one unexpected source of moonquakes could be the very equipment that Earth’s astronauts left behind. Continue reading “Scientists Call Out Apollo 17 After Investigating Moonquakes Past” →

The Hunt For The Voice Of Utah’s Arches

March 8, 2022 by Ryan Flowers 11 Comments

In the 1990 movie The Hunt For Red October, a stealth submarine is located by what a computer thinks are seismic sounds, but when sped up, they are clearly mechanical. We won’t spoil it further on the off chance that you haven’t seen. We can’t help but wonder if [Prof. Jeff Moore] and his team at the University of Utah were inspired by the movie. Why so? Because they have taken the seismic vibrations of the beautiful arches in Utah, US and sped them up 25 times, placing them right in the range of human hearing on their Red Rock Tones website. Go have a quick listen. We’ll be right here.

The resulting sound bites are just beautiful, and some of them have an almost eerie underwater tone to them as if driven along by a clandestine propulsion system. But that might just be our imagination running away a bit. That’s likely the point of this scientific exercise, however- taking raw scientific data and making it accessible and somehow relevant to even non-geologists.

The Dynamics of Rock Arches All Images Courtesy Prof Jeff Moore

[Prof Moore] and his team aren’t just placing seismometers on natural rock arches for the fun of it, even though that does sound like some fun. Instead, they are studying the natural resonances of these rock formations- both the primary frequencies and the harmonics. By monitoring changes in their resonant frequencies over time, they gain an understanding of how the rock is changing- especially as it relates to the impact that humans have on these natural wonders.

What’s more, these audible representations of seismic waves are something that may be possible for the determined hacker. We’ve featured several DIY seismometers such as this hacked USB mouse designed to detect elephants on the move. Could it be sensitive enough for measuring seismic activity? Try it out, and let us know!

Special thanks to [Prof. Jeff Moore] for permission to use the images for this article.

A Web Connected Seismometer

December 6, 2014 by Ethan Zonca 7 Comments

[10DotMatrix] has a budding interest in seismology, so she decided to make her own seismometer out of some easy-to-find materials. Seismometers are prohibitively expensive for hobbyists, but thankfully it’s really easy to build a usable siesmometer out of simple parts. [10DotMatrix]’s seismometer is built around a modified subwoofer, which acts as a transducer for the earth’s vibrations.

The subwoofer is mounted to the bottom of a tripod, which forms the structure of the seismometer. A slinky is stretched between the top of the tripod and a weight that rests on the coil of the subwoofer. Whenever the ground shakes, the slinky and weight vibrate and induce current in the voice coil.

Since these vibrations are usually quite small, the output of the subwoofer needs a bit of amplification. [10DotMatrix] fed the output of the woofer to an AD620 op amp, which amplifies the signal to a measurable level. The amplifier’s output is fed into an Intel Edison board, which samples the voltage and transmits it to a web dashboard for online viewing.

If you’re shaking with excitement about seismic measurements you’ll surely be interested in this similar method which uses a piezo element as the detector.

Detecting Seismic Waves With A Piezo Element

December 11, 2011 by Mike Nathan 14 Comments

While we normally see piezo elements being used to output audio, [Veedo] thought that they could be used in a more useful manner. He bought way too many piezo film tabs and decided to use them to build a makeshift seismic sensor.

The piezo tabs came with weights attached at one end, though while testing them, he found that they more or less only detected vibrations with frequencies in the KHz range. Since earthquakes tend to produce vibrations in the 30-80 Hz range, he had to tweak his setup to detect the proper frequencies. To do this, he attached a weight made of a screw and washers, checking the output signals on his oscilloscope until the dominant sensed frequencies were in the range of 40 Hz.

The sensor was attached to a breadboard, then wired through a charge amp to create a small AC signal, which floats on 2.5Vdc. The bottom half of the wave is chopped off with a diode, after which it is fed into an Arduino Mega. The seismic data is then pushed up to his Pachube account for storage, though he can view the feeds locally via the a web server programmed into the Arduino.

We’re not sure how much advanced notice this sort of setup would give you in the event of an earthquake, but it seems like a fun project to build either way.