Author: Al Williams

4490 Articles

Ask Hackaday: Do You Need A Tablet?

April 29, 2026 by 92 Comments

There’s an old saying that the happiest days of a boat owner’s life are the day they buy the boat, and the day they sell it. For me, the happiest days of an Android tablet owner’s life are the day they buy a new one, and the day they buy a newer one. For some reason, I always buy tablets with great expectations, get them set up, and then promptly lose them in a pile on my desk, not to be seen again. Then a shiny new tablet gets my attention in a year or so, and the cycle repeats.

You might be thinking that I just buy cheap junk tablets. It is true that I have. But I have also bought new Galaxy and Asus tablets with the same result. Admittedly, I have owned several Surface Laptops and Pros, and I do use them. But I can’t remember the last time I have used one without the keyboard. They aren’t really tablets — they are just laptops that can also be heavy, awkward tablets.

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A Guide To CubeSat Mission And Bus Design

April 28, 2026 by 9 Comments

If you mention the word bus, you might think of public transportation or, more likely for us, a way to connect things together. But in the satellite world, the bus is the part of a vehicle that supports the payload but isn’t itself the payload. Typically, that means the electric power system, propulsion, radios, and thermal control, among other systems. If you are designing a CubeSat, you will want to read A Guide to CubeSat Mission and Bus Design by [Frances Zhu].

The Creative Commons-licensed book has twelve chapters, ranging from systems engineering — that is, defining what you want to do — to analyzing structures, handling power, setting up communications, and more. Of particular interest to us was the chapter on command and data handling. The final chapters cover software, system integration, and there’s even a chapter on Ethics.

If you want to build a CubeSat or just want to learn more about how satellites actually work, this is a great read. There are videos and other features, too. If you don’t like reading in your browser, you can download an EPUB, PDF, or MOBI near the top of the page.

There are many resources for the want-to-be CubeSat builder. You can even start with an open source design.

Why Solid State Batteries Short

April 27, 2026 by 14 Comments

Solid state batteries, we are told, are the new hot battery technology that will replace lithium-ion batteries. Soon. Not that we haven’t heard that before. One reason it isn’t dominating the market today is that it’s prone to short circuits during charging. [Dr. Yuwei Zhang and others have published a paper detailing why the shorts happen, which could lead to strategies to improve the technology.

Solid state batteries employ a solid electrolyte and a lithium anode. It is known that, sometimes, lithium metal from the anode forms dendrites that penetrate the ceramic electrolyte and cause it to crack. This is somewhat of a mystery as the lithium is a soft metal: to quote [Zhang], “like a gummy bear”.

There were two leading hypotheses for the observations. [Zhang’s] team showed that hydrostatic stress made the lithium dendrites act like a water jet, enabling them to penetrate the hard ceramic.

There is still work to figure out what to do about it, but understanding the root cause is certainly a step in the right direction. We’ve looked at these batteries before. We’ve also seen how changing the anode construction might help with the problem.

Register Renaming

April 27, 2026 by 13 Comments

[Shreeyash] asks an interesting question: how many registers does your CPU have? The answer is probably more than you think. The reason? Modern CPUs — at least many of them — execute instructions out of sequence so they can perform multiple instructions per clock cycle. To do this, they may need to execute instructions that change registers that other instructions are still reading. In addition, you might be writing a result speculatively — a branch might make it where your result won’t wind up in the target register. The answer to both of these problems is register renaming.

The ARM CPU he looks at has many physical registers you can’t see. These get mapped to the registers you use on the fly. So when you read a register in software, you are really getting an underlying physical register. Which one? Depends on when you read it.

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The Arduino UNO, Basically

April 26, 2026 by 25 Comments

If you miss the days when you used Basic on your classic computer or wrote embedded software with a Basic Stamp, then maybe dust off your Arduino UNO or any similar AVR board and try nanoBASIC_UNO from [shachi-lab].

Apparently, the original code was meant for the STM8S, but this port targets the ATmega328P. It is Basic more or less as you remember it. There are enough extensions to deal with GPIO, the analog systems, and so forth. At build time, you can decide if you want 16-bit or 32-bit integers.

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Hackaday Podcast Episode 367: Radioactive Weather, Continuous Pickles, And Moon Junk

April 24, 2026 by 5 Comments

When Elliot Williams and Al Williams compare their notes on the week in Hackaday, you know you’ll get at least one or two bad puns. How bad? Tune in and find out.

This week, Tom Nardi visits several in-person events, and Elliot and Al talk about smart buttons, Itanium, ejecting things from a rocket, and the infinite pickle. Will Elliot build the coin flipper? Will Al use plasma at his next cookout? Hard to say.

For the can’t miss articles, this week, Al swept the category with a post on splices and another on what human junk is still sitting on the moon.

What do you think? Leave us a comment or record something and send it to our mailbag.

Download a copy of the podcast with an MP3 from our continuous audio pipeline.

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Spool Roller Gets Touch Screen

April 24, 2026 by 2 Comments

If you have a desktop 3D printer, you probably want something to hang filament spools on. [LVTRC] has a spool roller that fits the bill. It also incorporates a scale and a round touch screen. (Google Translate)

We’ve seen those round screens before, and now we wonder why we didn’t think of this. The GC9A01 display shows a progress ring and lets you save settings or calibrations to EEPROM. An Arduino Nano provides the brain, and the load cell connects to an HX711. The project is made to fit a specific printer, but it should be little trouble to adapt it to a different printer or to mount it in an external mount.

One of the calibration steps, of course, is to program the weight of an empty spool to subtract from the total weight. The device can store up to five specific profiles.

Not the biggest spool holder we’ve seen. We keep thinking that we don’t know why we want a circular screen, and then someone always drops in to show us another thing we didn’t think about.