Author: Al Williams

4387 Articles

Size (and Units) Really Do Matter

January 23, 2026 by 93 Comments

We miss the slide rule. It isn’t so much that we liked getting an inexact answer using a physical moving object. But to successfully use a slide rule, you need to be able to roughly estimate the order of magnitude of your result. The slide rule’s computation of 2.2 divided by 8 is the same as it is for 22/8 or 220/0.08. You have to interpret the answer based on your sense of where the true answer lies. If you’ve ever had some kid at a fast food place enter the wrong numbers into a register and then hand you a ridiculous amount of change, you know what we mean.

Recent press reports highlighted a paper from Nvidia that claimed a data center consuming a gigawatt of power could require half a million tons of copper. If you aren’t an expert on datacenter power distribution and copper, you could take that number at face value. But as [Adam Button] reports, you should probably be suspicious of this number. It is almost certainly a typo. We wouldn’t be surprised if you click on the link and find it fixed, but it caused a big news splash before anyone noticed.

Thought Process

Best estimates of the total copper on the entire planet are about 6.3 billion metric tons. We’ve actually only found a fraction of that and mined even less. Of the 700 million metric tons of copper we actually have in circulation, there is a demand for about 28 million tons a year (some of which is met with recycling, so even less new copper is produced annually).

Simple math tells us that a single data center could, in a year, consume 1.7% of the global copper output. While that could be true, it seems suspicious on its face.

Digging further in, you’ll find the paper mentions 200kg per megawatt. So a gigawatt should be 200,000kg, which is, actually, only 200 metric tons. That’s a far cry from 500,000 tons. We suspect they were rounding up from the 440,000 pounds in 200 metric tons to “up to a half a million pounds,” and then flipped pounds to tons.

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Embedded TPM: Watch Out!

January 23, 2026 by 63 Comments

Today’s PCs are locked up with Trusted Platform Module (TPM) devices so much so that modern Windows versions insist on having a recent TPM to even install. These have become so prevalent that even larger embedded boards now have TPM and, of course, if you are repurposing consumer hardware, you’ll have to deal with it, too. [Sigma Star] has just the primer for you. It explains what TPM does, how it applies to embedded devices, and where the pitfalls are.

The TPM is sometimes a chip or sometimes secure firmware that is difficult to tamper with. They provide secret storage and can store boot signatures to detect if something has changed how a computer starts up. The TPM can also “sign off” that the system configuration is the same to a remote entity. This allows, for example, a network to prevent a hacked or rogue computer from communicating with other computers.

Embedded systems, usually, aren’t like PCs. A weather station at a remote location may have strangers poking at it without anyone noticing. Also, that remote computer might be expected to be working for many more years than a typical laptop or desktop computer.

This leads to a variety of security concerns that TPM 2.0 attempts to mitigate. For example, it is unreasonable to think a typical attacker might connect a logic analyzer to your PC, but for an embedded system, it is easier to imagine. There is a session-based encryption to protect against someone simply snooping traffic off the communication bus. According to the post, not all implementations use this encryption, however.

Motherboard has a slot for TPM, but no board? We’ve seen people build their own TPM boards.

Title image by [Raimond Spekking] CC BY-SA-4.0

A 1970s Electronic Game

January 22, 2026 by 2 Comments

What happens when a traditional board game company decides to break into electronic gaming? Well, if it were a UK gaming company in 1978, the result would be a Waddingtons 2001 The Game Machine that you can see in the video from [Re:Enthused] below.

The “deluxe console model” had four complete games: a shooting gallery, blackjack, Code Hunter, and Grand Prix. But when you were done having fun, no worries. The machine was also a basic calculator with a very strange keyboard. We couldn’t find an original retail price on these, but we’ve read it probably sold for £20 to £40, which, in 1978, was more than it sounds like today.

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Touchless Support Leaves No Mark

January 22, 2026 by 13 Comments

[Clough42] created a 3D print for a lathe tool and designed in some support to hold the piece on the bed while printing. It worked, but removing the support left unsightly blemishes on the part. A commenter mentioned that the support doesn’t have to exactly touch the part to support it. You can see the results of trying that method in the video below.

In this case [Cloug42] uses Fusion, but the idea would be the same regardless of how you design your parts. Originally, the support piece was built as a single piece along with the target object. However, he changed it to make the object separate from the support structure. That’s only the first step, though. If you import both pieces and print, the result will be the same.

Instead, he split the part into the original two objects that touch but don’t blend together. The result looks good.

We couldn’t help but notice that we do this by mistake when we use alternate materials for support (for example, PETG mixed with PLA or PLA with COPE). Turns out, maybe you don’t have to switch filament to get good results.

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STL Editing With FreeCAD

January 22, 2026 by 28 Comments

[Kevin] admits that FreeCAD may not be the ideal tool for editing STL files. But it is possible, and he shares some practical advice in the video below. If you want to get the most out of your 3D printer, it pays to be able to create new parts, and FreeCAD is a fine option for that. However, sometimes you download an STL from the Internet, and it just isn’t quite what you need.

Unlike native CAD formats, STLs are meshes of triangles, so you get very large numbers of items, which can be unwieldy. The first trick is to get the object exactly centered. That’s easy if you know how, but not easy if you are just eyeballing it.

If you use the correct workbench, FreeCAD can analyze and fix mesh problems like non-manifold parts, flipped normals, and other issues. The example is a wheel with just over 6,000 faces, which is manageable. But complex objects may make FreeCAD slow. [Kevin] says you should be fine until the number of faces goes above 100,000. In that case, you can decimate the number of faces with, of course, a corresponding loss in resolution.

Once you are satisfied with the mesh, you can create a real FreeCAD shape from the mesh. The resulting object will be hollow, so the next step will be to convert the shape to a solid.

That still leaves many triangles when you really want flat surfaces to be, well, flat. The trick is to make a copy and use the “refine shape” option for the copy. Once you have a FreeCAD solid, you can do anything you can do in FreeCAD.

We’ve run our share of FreeCAD tips if you want more. There are other ways to tweak STLs, too.

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Simulating Pots With LTSpice

January 21, 2026 by 9 Comments

One of the good things about simulating circuits is that you can easily change component values trivially. In the real world, you might use a potentiometer or a pot to provide an adjustable value. However, as [Ralph] discovered, there’s no pot component in LTSpice. At first, he cobbled up a fake pot with two resistors, one representing the top terminal to the wiper, and the other one representing the wiper to the bottom terminal. Check it out in the video below.

At first, [Ralph] just set values for the two halves manually, making sure not to set either resistor to zero so as not to merge the nets. However, as you might guess, you can make the values parameters and then step them.  Continue reading “Simulating Pots With LTSpice” →

Retrotechtacular: RCA Loses Fight To IBM

January 21, 2026 by 27 Comments

If you follow electronics history, few names were as ubiquitous as RCA, the Radio Corporation of America. Yet in modern times, the company is virtually forgotten for making large computers. [Computer History Archive Project] has a rare film from the 1970s (embedded below) explaining how RCA planned to become the number two supplier of business computers, presumably behind behemoth IBM. They had produced other large computers in the 1950s and 1960s, like the BIZMAC, the RCA 510, and the Spectra. But these new machines were their bid to eat away at IBM’s dominance in the field.

RCA had innovative ideas and arguably one of the first demand paging, virtual memory operating systems for mainframes. You can hope they were better at designing computers than they were at making commercials.

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