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Digital High Sensitivity Infrasound Monitor - Real Geophysics Research on a budget

Infrasound Monitor Presentation Paper #1 Construction Instructions
Tonga Event

Full documentation and software on the Downloads page above

Tonga Eruption Infrasound
Infrasound Pulse from Tonga Eruption late Saturday

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I have been working on a new geophysics project for the past three years, a compact infrasound monitor based on a digital, i2c enabled diferential pressure sensor. I feel this is a beauty. Very open-ended with lots of opportunities for students of all levels - primary to postgrad - to redesign and test replacement components. This is also real science, in a little studied area. Well suited to networking in small or large areas. Oh - and cheap! see Blog (above) for current status. A paper has been published in IOP Phys Ed.

The system may be used either as a fixed monitoring station or taken out for on-site measurements. We have successfully measured infrasound at windfarms, on beaches and in cars. Interesting we detected a clear signal from the Tonga eruption at a range of over 16,000km. This and the Aurora monitor were awarded by the Czech Society of Physics at the european 'Science on Stage' Festival in 2022.

http://schoolphysicsprojects.org/projects/infrasound/TongaEvent/

As examples of real data see Blog posts for:-

This rig capable of resolving to better than 1 3-millionth of an atmosphere will cost less than £100 and provide plenty of valuable experience in computing, physics, electronics, and signal processing to a small team for a year or so.

Infrasound is a little studied area of geophysics/environmental science ripe for further investigation. The only U.K. detector I can find reference to is possibly one run by A.W.E. at Blacknest. Unsurprisingly precious little information is extant. A national network of school & college infrasound detectors could potentially generate useful scientific data as well as remarkable educational benefits.

Code and instructions may be downloaded here - link.

Rig Alpha: Loftspace - pitched tile roof wind-filter - 40Hz sample rate
Current InfraSound Plot
ΔP 0.01-10Hz - updates hourly (54.53°N 1.08°W +100m)
Current InfraSound Plot
Acoustic Power 0.01-10Hz - updates hourly (54.53°N 1.08°W +100m)
Current InfraSound Plot
Weekly Infrasound Acoustic Power 0.01-10Hz - updates hourly (54.53°N 1.08°W +100m)
Rig Gamma: Outdoors - 15m porous hose on flat roof - 140Hz sample rate
Current InfraSound Plot
ΔP 0.01-10Hz - updates hourly (54.53°N 1.08°W +100m)
Current InfraSound Plot
Acoustic Power 0.01-10Hz - updates hourly (54.53°N 1.08°W +100m)
Current InfraSound Plot
Weekly Infrasound Acoustic Power 0.01-70Hz - updates hourly (54.53°N 1.08°W +100m)
Rig A: Archived plots ... Rig B: Archived plots .. Rig G: Archived plots

The above are simple daily data plots. These are generated on the fly by the Pi used to monitor the sensor, and should be used for quick observation of output. The idea being that the data be downloaded from the PI for more detailed analysis. I have written a general analysis tool in python for this - examples below and on the Blog page (above).

infrasound
v1 2018
infrasound monitor redcar beach
v2 - Redcar Beach 2019, purple usb powerbank, yellow Pi case, Orange sensor unit, black foam wind-filter
Police Helicopter Infrasound
Helicopter within 1km, foam block windfilter, 20 -> 30 min

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Current InfraSound Plot
Infrasound Monitor raw data Aug -11th 2017

Current InfraSound Plot
Infrasound Monitor 'demeaned' -dayplot Aug -11th 2017

Current InfraSound Plot
Infrasound Monitor acoustic power dayplot Aug -11th 2017

Current InfraSound Plot
Infrasound Monitor spectrum Aug -11th 2017