Hardware Store Marauder’s Map is Clarkian Magic

The “Marauder’s Map” is a magical artifact from the Harry Potter franchise. That sort of magic isn’t real, but as Arthur C. Clarke famously pointed out, it doesn’t need to be — we have technology, and we can make our own magic now. Or, rather, [Dave] on the YouTube Channel Dave’s Armoury can make it.

[Dave]’s hardware store might be in a rough neighborhood, since it has 50 cameras’ worth of CCTV coverage. In this case, the stockman’s loss is the hacker’s gain, as [Dave] has talked his way into accessing all of those various camera feeds and is using machine vision to track every single human in the store.

Of course, locating individuals in a video feed is easy — to locate them in space from that feed, one first needs an accurate map. To do that, [Dave] first 3D scans the entire store with a rover. The scan is in full 3D, and it’s no small amount of data. On the rover, a Jetson AGX is required to handle it; on the bench, a beefy HP Z8 Fury workstation crunches the point cloud into a map. Luckily it came with 500 GB of RAM, since just opening the mesh file generated from that point cloud needs 126 GB. That is processed into a simple 2D floor plan. While the workflow is impressive, we can’t help but wonder if there was an easier way. (Maybe a tape measure?)

Once an accurate map has been generated, it turns out NVIDIA already has a turnkey solution for mapping video feeds to a 2D spatial map. When processing so much data — remember, there are 50 camera feeds in the store — it’s not ideal to be passing the image data from RAM to GPU and back again, but luckily NVIDIA’s “Deep Stream” pipeline will do object detection and tracking (including between different video streams) all on the GPU. There’s also pose estimation right in there for more accurate tracking of where a person is standing than just “inside this red box”. With 50 cameras, it’s all a bit much for one card, but luckily [Dave]’s workstation has two GPUs.

Once the coordinates are spat out of the neural networks, it’s relatively simple to put footprints on the map in true Harry Potter fashion. It really is magic, in the Clarkian sense, what you can do if you throw enough computing power at it.

Unfortunately for show-accuracy (or fortunately, if you prefer to avoid gross privacy violations), it doesn’t track every individual by name, but it does demonstrate the possibility with [Dave] and his robot. If you want a map of something… else… maybe check out this backyard project.

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hackaday.com/2025/12/20/hardwa…

A comment about yesterday’s president 🇺🇦 #Zelensky visit in 🇵🇱 #Poland - the context was very sensitive but fortunately everything worked well. Why was it sensitive?

1. 🇵🇱 Nawrocki is in an awkward position where he must remain loyal to his right-wing electorate, but at the same time fulfill the duties president of Poland. It’s not a criticism, just a statement of fact that is usually true for any elected politician with one particular voter base.
2. Polish right-wing is a broad spectrum between people with moderate religious and conservative but generally pro-EU and pro-Ukrainian views (PiS), down to complete Putinist freaks. Most importantly, even anti-EU parties like “Konfederacja” are divided. Thanks to numerous splits, the 🇷🇺 freaks are now mostly concentrated in “Konfederacja Korony Polskiej”.
3. Polish “liberals” (KO) chose to appeal to the centrist and left-wing electorate primarily by vilifying the whole right-wing. Daily political activity in Poland is infantile bashing between KO ministers and Nawrocki on a level so miserably stupid that is only comparable to MAGA.
4. Mutual accusations of being “pro-Russian” because someone visited Moscow as a diplomat in 2009 are a daily occurrence. In reality, it was PiS government that took all the refugees and send the first heavy weapons (MiG-29, tanks) to Ukraine in the first days of 2022 when other countries reluctantly offered helmets. PiS had done many bad things, but this thing they’ve done right.
5. Because the narratives have to be 100% black-and-white and “liberals” took the Ukraine topic, Nawrocki clearly felt compelled to play the opposite side. That is, the right end of his spectrum, which I was concerned would mean appealing to freaks obsessively talking about Volhynia and nothing else.

If that would happen, if Nawrocki eventually took the tribal side and decided to “play hard” with Zelensky, that would be a total disaster. Once again it would demonstrate that Poland is unable to operate as a single country and is doomed to remain a chaotic and unpredictable tribal entity forever.

Fortunately, that did not happen. I’ve listened to the whole 🇵🇱 Nawrocki speech in the presence of Zelensky. Nawrocki said all the necessary things about joint strategic goals and unity, and didn’t say anything unnecessary. He did mention “difficult topics” like Volhynia exhumations but even that he mentioned in a non-confrontational context of ongoing cooperation, which is a fact. He talked about military cooperation too. And when he talked about Volhynia and “gratitude” because that’s important for his electorate.

🇺🇦 Zelensky’s talk was in the same tone, so I won’t go into details. Yes, we have common goals; yes, unity is critical; yes, there are difficult topics and we are jointly working on them; yes, we also cooperate on military topics and we will do more. ✅

They were talking business. No hugs, no kisses, but honest business talk, and that’s precisely what they needed. ✅

I was a bit concerned about the outcome of yesterday’s visit, but it all worked well. And it gave Polish PM Tusk later full right to say that the worst news from yesterday’s Presidents’ meeting came out to be for Russia. Tusk met with Zelensky too late at night after he came back from Brussels, bringing the news of 90b EUR “loan” for Ukraine.

Overall ✅✅✅ for both countries and Europe.

The ‘Hidden’ Microphone inside the Sipeed NanoKVM

Recently, [Jeff Geerling] dropped into the bad press feeding frenzy around Sipeed’s NanoKVM, most notably because of a ‘hidden’ microphone that should have no business on a remote KVM solution. The problem with that reporting is, as [Jeff] points out in the video below, that the NanoKVM – technically the NanoKVM-Cube – is merely a software solution that got put on an existing development board, the LicheeRV Nano, along with an HDMI-in board. The microphone exists on that board and didn’t get removed for the new project, and it is likely that much of the Linux image is also reused.

Of course, the security report that caused so much fuss was published back in February of 2025, and some of the issues pertaining to poor remote security have been addressed since then on the public GitHub repository. While these were valid concerns that should be addressed, the microphone should not be a concern, as it’d require someone to be logged into the device to even use it, at which point you probably have bigger problems.

Security considerations aside, having a microphone in place on a remote KVM solution could also be very useful, as dutifully pointed out in the comments by [bjoern.photography], who notes that being able to listen to beeps on boot could be very useful while troubleshooting a stricken system. We imagine the same is true for other system sounds, such as fan or cooling pump noises. Maybe all remote KVM solutions should have microphone arrays?

Of course, if you don’t like the NanoKVM, you could always roll your own.

Top image: the NanoKVM bundle from [Jeff]’s original review. (Credit: [Jeff Geerling])

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hackaday.com/2025/12/20/the-hi…

Two-Wheeled Arduino Robot Project for Beginners

Here’s a fun build from [RootSaid] that is suitable for people just getting started with microcontrollers and robotics — an Arduino-controlled two-wheeled robot.

The video assumes you already have one of the common robotics kits that includes the chassis, wheels, and motors, something like this. You’ll also need a microcontroller (in this case, an Arduino Nano), a L293D motor driver IC, a 9 V battery, and some jumper wires.

The video goes into detail about how the two wheels connected to one motor each can move the robot in various directions: forward, backward, left, and right. The motors can be made to spin either forward or backward, depending on the polarity of the power supply, using an H-bridge circuit.

The L293D motor driver IC powers and controls the motors connected to the wheels. The L293D takes its commands from the Arduino. The rest of the video is spent going over the software for controlling the wheels.

When you’re ready to go to the next level, you might enjoy this robot dog.

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hackaday.com/2025/12/20/two-wh…