Author: John Poole
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Train Tracker
<p>Once again, I am in need of knowing when trains travel nearby at the crossing of Court ST and other crossings nearby. This time is to confirm my readings from a pressure transducer (really just like a microphone but gives out voltages) on the assumption that freight trains emit infrasounds through the air. I’ve already…
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Confirmed: Milk Jug Transducer Captures Train Infrasounds
<p>Today is a milestone for I have proven that a $35 Sensirion <a title="https://www.digikey.com/en/products/detail/sensirion-ag/SDP810-125PA/6605488?s=N4IgTCBcDaIMoBEAKAOAjABgLRrAViQEMQBdAXyA" href="https://www.digikey.com/en/products/detail/sensirion-ag/SDP810-125PA/6605488?s=N4IgTCBcDaIMoBEAKAOAjABgLRrAViQEMQBdAXyA" data-from-md="">SDP810-125PA</a> differential pressure transducer, connected to an ordinary empty milk jug, detected low-frequency pressure fluctuations coinciding with a freight train passing approximately 1,300 feet away.This physical setup of using back pressure on a transducer is based on the article by…
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Local AI: PDF Digestion
<h1>Introduction</h1> <p>My local AI, the <a href="https://github.com/Niko1221/Strata">Strata</a> project model <strong>qwen3.8-flash-next-iq3_s,</strong> does not accept PDFs for upload.</p> <p>The interface <em>does</em> accept binary images. So if I want my chat to consider the contents of a PDF, I have to extract its text and images and then upload the text and images to my local chat. This…
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Local AI Test: Understanding An Electronic Circuit Diagram
I’ve installed several artificial intelligence (“AI”) models on my own computers; I’m exploring the quality of responses from local AI and comparing the results. This test is simply this a screenshot and a prompt. This is the screenshot: This is the prompt: What can you tell me about this screenshot? what is in it and…
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When A Freight Train Passes By, What Sub-20 Hz Ground Vibrations Do I Observe??
This post continues my previous post “My 1″ Geophone Tracked A Mighty Freight Train.” There we learned that a small geophone can measure seismic waves, i.e. ground waves, and that when a freight train comes by, there is a substantial increase of low frequency waves. The question then became: what frequencies, and by how much.…
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My 1″ Geophone Tracked A Mighty Freight Train
I have been working and experimenting for several weeks with geophones, transducers, and spectral analysis software in furtherance of my Hyperscale Data Center Sound Monitor project. Freight trains are known to emit low-frequency and infrasonic energy, so I have made it my business to become a temporary train tracker. I’m currently collecting 330 samples/second from…
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Baby’s First Infrasound Detection
Absolutely extremely technical I have a Sensirion transducer (SDP810-125PA at DigiKey $30.85) hooked up to an ESP32-S (ESP32-S3 Feather 8MB with w.FL Antenna at Adafruit $17.50). The transducer is for capturing infrasounds (< 20 Hz). Today was a milestone: the transducer detected an infrasound — its first “baby.” I am building this experimental device inspired…
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MEMs Microphone Investigation
<p><strong>Technical / DIY</strong> — for those interested in do-it-yourself sound monitoring of hyperscale data centers and related circuitry</p> <p>I’ve been mulling over Preston Blackburn’s Remote Audio Monitor design (see <a href="https://salemdata.net/johnpress/?p=1223">Monitor Sounds From a Data Center?</a>) and assessing its ability to monitor infrasound (<20hz) and low frequencies between 20 Hz and 50 Hz. Blackburn uses…
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Monitor Sounds From A Data Center?
A recent article, “[t]he complex corporate web behind a \$3.2 billion AI data center When multiple companies are behind one project, who bears responsibility for problems?” published by Ars Technica at link, intrigued me. There was a reference to a resident living in a house built in 1892 who complained of the constant noise from…
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Build Your Own Artificial Intelligence Camera System
<p>I have added artificial intelligence (“AI”) to my home surveillance camera system.</p> <p>No cloud service.</p> <p>No fees.</p> <p>No meters.</p> <p>Everything stays on premises and is totally under my control.</p> <p>The system I have designed is quite simple:</p> <ul> <li>you need a Raspberry Pi 4B (<a href="https://www.adafruit.com/product/4296">Adafruit</a> \$120 – \$190) or better,</li> <li>a Google Coral USB…