Additional detection of sound?

[pe1chl]

Has it ever been considered to add additional detection of sound to the system, or maybe to have a different (simpler) system that can be used to detect the origin of loud sounds?
As sound travels a lot slower than light, it would likely be sufficient to have an NTP-synced clock instead of a local GPS receiver.  But of course it never hurts to have it.
However, to have useful use of such a detection it needs more stations than the lightning detection system currently has.

Still, much of the basic principles would be the same, so maybe it could be done as an addition or as a second project within Blitzortung.org?

Application: location of the source of explosions, shootings, fireworks etc in a local area.

[mwaters]

Yes, it has been asked before. However, it would not be practical.

• https://forum.blitzortung.org/showthread.php?tid=1511
  
• https://forum.blitzortung.org/showthread...d#pid20724
  
• https://forum.blitzortung.org/showthread...d#pid11514
  

[pe1chl]

Thanks for reply!
I can only read the first article. It appears others are interested as well.
On the 2nd and 3rd link I get error messages (You do not have permission to access this page)

Interesting that the first article mentions the KNMI system.
There recently was a relatively big explosion here and it was recorded on a sensor of the KNMI system but as they do not have many sensors it was not possible to pinpoint the location.
Maybe when there would be sensors within reach of hobbyists it would be possible to get enough coverage for that...

Also in the current local news there is the discussion about the ban on consumer fireworks and the impossibility of efficiently finding the illegal users of fireworks. A locating system would help there.

[mwaters]

This network is about detecting lightning, and always will be.

Infra sound detection has been discussed, but it is not very useful for fast detection, and you would have to have a very high density of stations for that to work. Besides, all of the Blitzortung lightning receivers ever made have no provision for the detection of sound.

As for shooting and fireworks (illegal or not) ... nope. Ain't gonna happen.    

[kevinmcc]

Has it ever been considered to add additional detection of sound to the system, or maybe to have a different (simpler) system that can be used to detect the origin of loud sounds?
As sound travels a lot slower than light, it would likely be sufficient to have an NTP-synced clock instead of a local GPS receiver.  But of course it never hurts to have it.
However, to have useful use of such a detection it needs more stations than the lightning detection system currently has.

Still, much of the basic principles would be the same, so maybe it could be done as an addition or as a second project within Blitzortung.org?

Application: location of the source of explosions, shootings, fireworks etc in a local area.

You may want to check out the Raspberry Boom project.

https://raspberryshake.org/products/raspberry-boom/

[pe1chl]

You may want to check out the Raspberry Boom project.

https://raspberryshake.org/products/raspberry-boom/

Ah that is what I was looking for!
This is the type of device I would like to use.
It looks like they need to do a lot more work on the server side of things to make it more like lightningmaps.org but at least there is a project so maybe I could contribute to that.

Thanks for the information!

[mwaters]

That's pretty interesting, Kevin! I have always wanted to build a seismograph.

But this can do much more than just detect the earth shaking. And it ought to, for those prices.

[kevinmcc]

That's pretty interesting, Kevin! I have always wanted to build a seismograph.

But this can do much more than just detect the earth shaking. And it ought to, for those prices.

I have two of their Seismographs, a 1D and a 4D.

One in my house in Illinois and one in my mother's house in Iowa about 60 miles away.

They are very sensitive and work.

If you want one, I'd get the 1D unless you live in areas like Central California or Japan.

The 4D costs $160 more, due to the 3 large movement sensors which are only useful if you live in a very active area like Central California or Japan.

The 1D costs $215 which includes every thing you need other than Raspberry Pi and power supply.

The case is a must have in my opinion and very well made.

[pe1chl]

Do they have some TDOA/location-on-map software available?
Browsing the site it appears they only have local data for each site, no location of the source, is that correct?

[mwaters]

I saw that they have a mobile app, but I know nothing about it.

[mwaters]

If you want one, I'd get the 1D unless you live in areas like Central California or Japan.

I appreciate the advice! Looks like I can get what I need for $160. I am quite comfortable with putting that in a similar case I have, and whatever necessary wiring, soldering, and mechanical work etc.

But I have other priorities at present.

[mwaters]

I have the InfraSound Detector app installed on my Android tablet. I've never used it, but now I'm going to play with it some.

• InfraSound Detector allows you to detect infrasound signals below 20 Hz.
  
• InfraSound Detector is the App that allows you to detect infrasound (infrasonic) acoustic signals below the user-defined frequency (up to 30 Hz by default).
  
• Infrasound propagates hundreds of miles and can penetrate walls, mountains and other obstacles without loss.
  

This detector can be useful in following cases:

• To find out any suspicious low frequency noise, vibrations, and sounds in building structures.
  
• To register a number of hazardous atmospheric phenomena, including aircraft wake vortices, clear air turbulence, severe thunderstorms and tornadoes as well as any seismic events and volcano activities. As a benefit, it allows early detection of tornadoes from hundreds of miles away.
  
• To detect underground activity, e.g., tunnel digging.
  
• To detect some kind of infrasonic weapons, that cause physical pain without human detection.
  
• To check out the quality of bass sounds (low frequency) of your subwoofer speaker system as well as any loudspeakers.
  

Result of detection can be shown on the screen in the foreground mode and also be presented in the notification form and (or) by sound (vibration) in the background mode when the screen of the Android device is turned off. All events can be recorded in the log for later analysis. The lower working frequency is depend on the audio specification of the current Android device and can be reached as low as 4 Hz. For better result, the high quality Android device with internal microphone should be used to determine the infrasound signal, but sensitivity on the lowest frequencies will be worse anyway. Also, you can use a special external infrasound microphone connected to the audio jack (microphone input of the ear plug connector).

The idea of the App is based on the fact that any analog system (microphone and amplifier of your Android device in this case) does NOT have ideal characteristics and infrasound signals can be infiltrate through it down to 4 Hz.

Features:

• Completely NO ads.
  
• The signal level indication.
  
• Vibration indication of the alarm event.
  
• Event log is recorded automatically. Signal spectrum and location information can be included in the log.
  
• The converter infrasonic signals into audible sounds. So you can hear infrasonic signals.
  
• Background mode with notifications. Once this option starts, the App runs quietly in the background and requires no human interaction until the alarm event happens. It continues to run even after the device reboots.
  
• Adjustable battery consumption in the background mode. The App is designed to conserve your device battery and allows to select the data update rate. The more update rate time, the less battery it takes.
  
• Comprehensive spectrum analysis with different ways to display results: spectrum, waterfall, oscilloscope.
  
• Adjustable frequency range and selectable frequency resolution between 0.1 and 1 Hz.
  

[SJ Clay]

I am interested from an infrasound perspective of correlating lightening strikes and thunder. Where can I get additional historic information on individual strikes (i.e. Intensity, duration, ...).

Thanks
Scott

[mwaters]

I am interested from an infrasound perspective of correlating lightening strikes and thunder. ...

See the links in post #2 above. They show that it is not practical.

[SJ Clay]

Thanks Mike,

I had seen that, dated and not really the case.

There are a number of papers that have been published on infrasound, thunder, lightening and sprites. Working in the Infrasound community I have seen signals, on infrasound arrays, with characteristics similar to those reported.  I have just started looking to gathering information about recent thunderstorms in my region and I am looking for any databases with time, lat/lon, and any other information that might be reported. 

Thanks,

Scott

[mwaters]

Okay, it sounds like you are talking about Infrasound as a stand-alone method of detection. A few questions come to mind.

1. Is this method actually in use anywhere?
   
2. What is the range of such a detection method?
   
3. What is the approximate accuracy?
   
4. Strong winds can blow sound waves around. That being the case, how is that compensated for?
   
5. What station density is required for this?
   

[SJ Clay]

Yes using Infrasound Arrays and characterizing the detected signals.

1. There are a number of arrays spread out across the country.  Some are part of our nuclear monitoring (CTBTO), some monitoring Volcanos, and still others for research.
2. It depends on the source strength, weather and propagation frequencies.  With the right atmosphere, a small explosive source can be detected from several hundreds of kilometers. Strong winds blowing the source signal away from the receiver can make that signal undetectable. 
3. Accuracy is an interesting question, infrasound propagation is as you can imagine directly affected by the atmosphere. So how do you quantify accuracy, you should or should not see signal based on what? Infrasound modeling is a developing science, so in short as a community we see a lot, and often we can explain why we see or don't see signals. 
4. The folks looking at Tornados using infrasound face that problem.  in this case you need to have your arrays upstream of the weather front and determine the density of arrays necessary to do that detection. 
5. An adequate array will having at least five elements (elements one in the center, with the other four elements to the north, East, South and West) with at least 50m between elements. That is suitable for monitoring the signals that most infrasound sources produce.

[mwaters]

Thank you, Scott.