Latest Posts (20 found)
Jeff Geerling Yesterday

Converting hot dog plasma video to sound with OpenCV

When you ground a hot dog to an AM radio tower, it generates plasma. While the hot dog's flesh is getting vaporized, a tiny plasma arc moves the air around it back and forth. And because this tower is an AM tower, it uses Amplitude Modulation , where a transmitter changes the amplitude of a carrier wave up and down. Just like a speaker cone moving up and down, the plasma arc from the hot dog turns that modulation into audible sound.

Science Electronics
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Jeff Geerling 3 days ago

It's not that hard to stop a Trane

Six years ago, I replaced the old HVAC system that came with our house, a central forced air system installed in 1995 1 . The new system is a Trane XR AC paired with an S9V2 96% efficiency forced-air gas furnace . And it ran great! Better efficiency, quieter, multiple fan speeds so I can circulate air and prevent stale air in some parts of the house... what's not to love? Well, apparently the engineering:

hardware Hardware
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Jeff Geerling 1 weeks ago

The Arduino Uno Q is a weird hybrid SBC

The Arduino Uno Q is... a weird board. It's the first product born out of Qualcomm's buyout of Arduino . It's like if you married an Intel CPU, and a Raspberry Pi RP2040 microcontroller—oh wait, Radxa's X4 did that . Arduino even tried it before with their old Yún board, which had Linux running on a MIPS CPU, married to an ATmega microcontroller.

Electronics hardware Hardware open-source Open Source
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Jeff Geerling 2 weeks ago

Why do some radio towers blink?

One day on my drive home, I saw three towers. One of them had a bunch of blinking white lights, another one had red lights that kind of faded in and out, and the third one, well, it wasn't doing anything. I'm lucky to have a radio engineer for a dad, so Dad: why do some towers blink? Joe: Well, blinking I would call like the way you described it, "flashing", "white light", or "strobe". All these lights are to aid pilots and air traffic. helicopters, fighter planes, regular jets. So that's the purpose of it. Jeff: Well that one tower that I saw had red lights that faded in and out, but I even think there's a freestanding tower just north of here that has red and white on top.

Electronics hardware Hardware
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Jeff Geerling 3 weeks ago

VCF Midwest was even better than I expected

Earlier this year, I inherited a bunch of old Macs and computer parts, including the PowerBook 520 pictured above. And, for the past three years I've been trying to visit VCF Midwest up in Chicago, where there's this odd blend of old computers, radio, broadcast gear... Honestly, it's hard to pin down exactly what it is. And I also had no idea how overwhelming the two-day event would be. Overwhelmingly awesome , that is.

hardware Hardware Electronics
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Jeff Geerling 1 months ago

Resizeable BAR support on the Raspberry Pi

While not an absolute requirement for modern graphics card support on Linux, Resizeable BAR support makes GPUs go faster, by allowing GPUs to throw data back and forth on the PCIe bus in chunks larger than 256 MB. In January, I opened an issue in the Raspberry Pi Linux repo, Resizable BAR support on Pi 5 .

hardware Hardware linux Linux performance Performance
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Jeff Geerling 1 months ago

How much radiation can a Pi handle in space?

Late in the cycle while researching CubeSats using Pis in space , I got in touch with Ian Charnas 1 , the chief engineer for the Mark Rober YouTube channel. Earlier this year, Crunchlabs launched SatGus , which is currently orbiting Earth taking 'space selfies'.

hardware Hardware Science programming Programming
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Jeff Geerling 1 months ago

Qualcomm's buying Arduino – what it means for makers

Qualcomm just announced they're acquiring Arduino , the company that introduced a whole generation of tinkerers to microcontrollers and embedded electronics. The Uno R3 was the first microcontroller board I owned. Over a decade ago, I blinked my first LED with an Uno; the code for that is actually still up on my GitHub .

Electronics hardware Hardware
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Jeff Geerling 1 months ago

The AI Emperor Has No Clothes

If the size of the current AI bubble can be estimated by how many I receive per day... then I'd say we're nearing the pop. There is no way the trillions of dollars of valuation placed on AI companies can be backed by any amount of future profit.

business Business ai AI
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Jeff Geerling 1 months ago

Not all OCuLink eGPU docks are created equal

I recently tried using the Minisforum DEG1 GPU Dock with a Raspberry Pi 500+, using an M.2 to OCuLink adapter, and this chenyang SFF-8611 Cable . After figuring out there's a power button on the DEG1 (which needs to be turned on), and after fiddling around with the switches on the PCB (hidden under the large metal plate on the bottom; TGX to OFF was the most important setting), I was able to get the Raspberry Pi's PCIe bus to at least tell the graphics card installed in the eGPU dock to spin up its fans and initialize. But I wasn't able to get any output from the card (using this Linux kernel patch ), and did not show it. (Nor were there any logs showing errors in ).

hardware Hardware linux Linux
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Jeff Geerling 1 months ago

Full eGPU acceleration on the Pi 500+ with a 15-line patch

Instead of a traditional review of a new Pi product, I thought I'd split things up on my blog, and write two separate posts; this one about hacking in an eGPU on the Pi 500+, for a massive uplift in gaming performance and local LLMs, and a separate post about the Pi 500+'s new mechanical keyboard . The Raspberry Pi 500+ was announced today, sells for $200, and adds on the following over what was present in the regular Pi 500:

hardware Hardware gaming Gaming
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Jeff Geerling 1 months ago

Testing the Raspberry Pi 500+'s new mechanical keyboard

Instead of a traditional review of a new Pi product, I thought I'd split things up on my blog, and write two separate posts; this one about the Pi 500+'s new mechanical keyboard, and a separate post about hacking in an eGPU on the Pi 500+ , for a massive uplift in gaming performance and local LLMs. The Raspberry Pi 500+ was announced today, sells for $200, and adds on the following over what was present in the regular Pi 500:

hardware Hardware gaming Gaming
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Jeff Geerling 1 months ago

You can finally manage Macs with FileVault remotely in Tahoe

It's nice to have a workstation set up that you can access anywhere via Screen Sharing to check on progress, jot down a note, etc.—and not be tied to a web app or some cloud service. I run a Wireguard VPN at home and at my studio, so I can remotely log into any of my infrastructure through the VPN—Macs included.

devops DevOps security Security
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Jeff Geerling 1 months ago

I regret building this $3000 Pi AI cluster

I ordered a set of 10 Compute Blades in April 2023 (two years ago), and they just arrived a few weeks ago. In that time Raspberry Pi upgraded the CM4 to a CM5, so I ordered a set of 10 16GB CM5 Lite modules for my blade cluster. That should give me 160 GB of total RAM to play with. This was the biggest Pi cluster I've built, and it set me back around $3,000, shipping included:

hardware Hardware ai AI
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Jeff Geerling 1 months ago

Save video still frames from QuickTime Player with a shortcut

Almost 15 years ago, I wrote Grab a Single Frame from a Video in QuickTime X . And for many years since, I slightly modified that workflow. Instead of using Preview, I would use , and paste the copied frame from QuickTime player into a file. For example: However, there are two problems with that workflow:

tutorial Tutorial
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Jeff Geerling 1 months ago

Digging deeper into YouTube's view count discrepancy

For a great many tech YouTube channels, views have been markedly down from desktop ("computer") users since August 10th (or so). This month-long event has kicked up some dust—enough that two British YouTubers, Spiffing Brit and Josh Strife Hayes are having a very British argument 1 over who's right about the root cause. Spiffing Brit argued it's a mix of YouTube's seasonality (it's back to school season) and channels falling off, or as TechLinked puts it, " git gud ", while Josh Strife Hayes points out the massive number of channels which identified a historic shift down in desktop views (compared to mobile, tablet, and TV) starting after August 10. This data was corroborated by this Moist Critical video as well.

data Data media Media Analytics
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Jeff Geerling 1 months ago

CubeSats are fascinating learning tools for space

These are CubeSats. Satellites that are going to space—or at least, the ones I have here are prototypes . But these have one thing in common: they're all powered by either a Raspberry Pi, or a microcontroller.

open-source Open Source programming Programming hardware Hardware
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Jeff Geerling 2 months ago

YouTube views are down (don't panic)

September 15 update : @YouTubeInsider confirmed that the issue is related to viewers who have adblockers enabled—YouTube's been in an arms race with ad blocking tools , and the fallout is a substantial cut in counted views for creators who have a large audience watching from desktop. Many YouTube content creators, myself included, noticed something in early to mid-August: views were down. After being on the platform since 2006 (though for me, not being a 'professional' YouTuber until about 5 years ago), I'm used to seasonal dips, adjustments after new tweaks to the algorithm or layout/design changes. But this was substantial .

business Business media Media
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Jeff Geerling 2 months ago

I bought the cheapest EV (a used Nissan Leaf)

I bought a used 2023 Nissan Leaf in 2025, my first 'new' car in 15 years. The above photo was taken by the dealership; apparently their social media team likes to post photos of all purchasers. I test drove a Tesla in 2012, and quickly realized my mistake. No gasoline-powered car (outside of supercars, maybe? Never drove one of those) could match the feel of pressing the throttle on an electric. I started out with a used minivan, which I drove into the ground. Then I bought a used Olds that I drove into the ground. Then I bought a used Camry that I bought before we had kids, when I had a 16 mile commute.

entertainment Entertainment
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