Category: Electronics
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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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An In-House Text-to-Speech Service for ESP32 Projects
Making your ESP32 Talk. YouTuber Dronebotworkshop published a video “Text to Speech on ESP32 – Wit.ai & OpenAI TTS“. “Text to Speech” is often referred to by the acronym TTS. His solution encompasses using third-party services, specifically Meta and OpenAI. For Meta, you have to have an account and you create an application within your…
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Reticulum: A Precision Trace Among 7 Nodes
What actually happens inside a Reticulum mesh running over LoRa when two endpoints cannot communicate directly? I built a seven-node testbed using LilyGo T-Beam SUPREME units named AMY, BOB, CY, DAN, ED, FLO, and GUY. AMY and GUY exchange one encrypted “Hi” message per minute, while software-defined radio blocks force their traffic through the other…
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Testing Satellite Time Synchronization Across Seven T-Beams
<p>The LilyGO T-Beam Supreme has a real time clock, aka “RTC”, circuit powered by a small hidden rechargeable battery that can hold a charge for 2-3 days. If your T-Beam is without power from A) its larger battery, a 18650 Li-Ion battery or B) a powered USB connector, then your stored date and time value…
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Achieving 166 µs Clock Synchronization Across 7 T-Beams
After much effort, I finally achieved running 7 T-Beams for 17 minutes, and having them create internal clocks based on satellite pulse per second, aka “PPS”, and finding they spanned by 166 µs. One hurdle I had to overcome was a physical one: 1) the top of the T-Beam contains the GPS antenna which is…
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Herding T-Beam Cats
Highly technical, but written for those who are blessed with curiosity Introduction I’m testing microReticulum, a C++ implementation of the Reticulum protocol developed by Chad Attermann, on 7 LilyGo T-Beam SUPREMEs. The T-Beams use the ESP32-S, a game-changing small processor. I’ve built an elaborate testing bench which I wanted to document should someone in the…
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Bluetooth Signal Strength Testing
<p>Now that I have Bluetooth working with Reticulum on the T-Beam, I have the option of testing my Reticulum mesh using Bluetooth instead of Lora. Were I using LoRa, I would have several people walking the neighborhood in an expanding circle fashion so that each node can only reach one other node. This requires having…
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Hardware-in-the-Loop AI Debugging: Reticulum Bluetooth on the T-Beam Supreme Works
Highly Technical Harnessing AI to control USB-connected devices can dramatically shorten hardware debugging cycles. I have successfully integrated the ble-reticulum C++ (protocol created by Torlando) interface into the microReticulum code. I built a binary image for the ESP32-based LilyGo! T-Beam SUPREME which I loaded into two T-Beams. The two T-Beams then negotiate a Bluetooth “pairing”…
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T-Beam Magnetometer Investigation
<p>5/1/2026 – <strong>Update</strong>: over 100k hits on my Forgejo server, presumably bots, so I now require sign-in to explore. Contact me if you want an account.</p> <h1>Introduction</h1> <p>This is a <em>deep technical</em> dive, possibly only of interest to people programming the LilyGO T-Beam SUPREME. Much of the working below are snippets taken from Wikipedia. What’s…