Salem Data Blog

Category: Electronics

  • Testing Satellite Time Synchronization Across Seven T-Beams

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    John Poole
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    <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…

  • Achieving 166 µs Clock Synchronization Across 7 T-Beams

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    John Poole
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    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…

  • Herding T-Beam Cats

    Herding T-Beam Cats

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    John Poole
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    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…

  • Bluetooth Signal Strength Testing

    Bluetooth Signal Strength Testing

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    John Poole
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    <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…

  • Hardware-in-the-Loop AI Debugging: Reticulum Bluetooth on the T-Beam Supreme Works

    Hardware-in-the-Loop AI Debugging: Reticulum Bluetooth on the T-Beam Supreme Works

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    jlpoole
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    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”…

  • T-Beam Magnetometer Investigation

    T-Beam Magnetometer Investigation

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    John Poole
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    <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…

  • Using Low-Cost GNSS Receivers to Pre-Qualify Survey Sites for NOAA OPUS

    Using Low-Cost GNSS Receivers to Pre-Qualify Survey Sites for NOAA OPUS

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    John Poole
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    Motivation Most GNSS survey failures are not due to equipment—they are due to poor site selection.  Survey-grade GNSS equipment paired with NOAA OPUS processing can achieve centimeter-level accuracy, but deployment is not trivial.  Site quality—sky visibility, multipath, and obstruction—directly impacts results. The central question: Can low-cost GNSS receivers be used as a reconnaissance tool to…

  • Live Tracking T-Beam SUPREME

    Live Tracking T-Beam SUPREME

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    John Poole
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    With ChatGPT, I have created C++ code which is uploaded to four T-Beam SUPREME units and causes each unit to send every 10 seconds its coordinates.  Each unit records it’s transmission and it records on its SD card incoming transmissions from the other units.  In addition, I have a base station “sniffer” Lora (Semtech 1303…

  • T-Beams Of Bable

    T-Beams Of Bable

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    John Poole
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    I have five LilyGO T-Beam SUPREMEs all transmitting and receiving every 15 seconds via Lora radio (Semtech 1302 chip).  This is a test of mutliple units being active and then seeing how well a Lora sniffer works.  The units are named: Amy Bob Cy Dan Ed I also have a Lora sniffer using the Semtech…

  • Lithium Battery Alert

    Lithium Battery Alert

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    John Poole
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    <p>Adam Savage of Myth Busters Fame released a 21′ <a href="https://www.youtube.com/watch?v=-Y23nfAOiXQ">video</a> “The Surprising Flaws in 18650 Lithium-Ion Batteries”on YouTube on January 20, 2026.  Adam has 7,100,000 subscribers.  Adam interviews these two employees from <a href="https://www.lumafield.com">Lumafield</a>:</p> <ul> <li><a href="https://www.linkedin.com/in/jualexju">Alex Hao</a></li> <li><a href="https://www.linkedin.com/in/andreas-l-bastian/">Andreas Bastian</a></li> </ul> <p>The upshot is that Lumafield has used a scanning device to see…