The Apple Watch As An Ammeter

September 10, 2024 by Jenny List 3 Comments

Your shiny new personal electronic device is likely to be designed solely as an app platform to run the products of faceless corporations, so the story goes, and therefore has an ever smaller hacking potential. Perhaps that view is needlessly pessimistic, because here’s [JP3141] with an example that goes against the grain. It’s an Apple Watch, being used as an ammeter. How it does that comes as the result of a delicious piece of lateral thinking.

Like many mobile devices, the device comes with a magnetometer. This serves as an electronic compass, but it’s also as its name might suggest, an instrument for sensing magnetic fields in three axes. With a 3D printed bobbin that slides over the watch, and a few turns of wire, it can sense the magnetic field created by the current, and a measurement can be derived from it. The software on the watch is only a simple proof of concept as yet, but it applies some fairly understandable high-school physics to provide a useful if unexpected measure of current.

We’re surprised to see just how many times the Apple Watch has appeared on these pages, but scanning past projects it was a cosmetic one which caught our eye. Who wouldn’t want a tiny Mac Classic!

Cruise Ship-Lengthening Surgery: All The Cool Companies Are Doing It

September 10, 2024 by Maya Posch 56 Comments

Sliding in an extra slice of cruise ship to lengthen it. (Credit: Silversea cruises)

The number of people going on cruises keeps rising year over year, with the number passengers carried increasing from just over 3.7 million in 1990 to well over 28 million in 2023. This has meant an increasing demand for more and also much larger cruise ships, which has led to an interesting phenomenon where it has become more economical to chop up an existing cruise ship and put in an extra slice to add many meters to each deck. This makes intuitively sense, as the segment added is fairly ‘dumb’, with no engine room, control systems, but mostly more rooms and cabins.

The current top-of-the-line cruise ship experience is exemplified by the Icon class that’s being constructed for the Royal Caribbean Group. The first in this line is the Icon of the Seas, which is the largest cruise ship in the world with a length of 364.75 meters and a gross tonnage of 248,663. All of this cost €1.86 billion and over two years of construction time, compared to around $80 million and a few months in the drydock. When combined with a scheduled maintenance period in the drydock, this ‘Jumboization’ process can be considered to be a great deal that gives existing cruise ships a new lease on life.

Extending a ship in this manner is fairly routine as well, with many ships beyond cruise ships seeing the torch before being split. A newly built segment is then slid in place, the metal segments are welded together, wires, tubing and more are spliced together, before the in and outside are ready for a new coat of paint that makes it seem like nothing ever happened to the ship.

Continue reading “Cruise Ship-Lengthening Surgery: All The Cool Companies Are Doing It” →

Misleading GPS, Philosophy Of Maps, And You

September 10, 2024 by Bryan Cockfield 19 Comments

The oft-quoted saying “all models are wrong, but some are useful” is a tounge-in-cheek way of saying that at some level, tools we use to predict how the world behaves will differ from reality in some measurable way. This goes well beyond the statistics classroom it is most often quoted in, too, and is especially apparent to anyone who has used a GPS mapping device of any sort. While we might think that our technological age can save us from the approximations of maps and models, there are a number of limitations with this technology that appear in sometimes surprising ways. [Kyle] has an interesting writeup about how maps can be wrong yet still be incredibly useful especially in the modern GPS-enabled world. Continue reading “Misleading GPS, Philosophy Of Maps, And You” →

Why Have Seven Segments When You Can Have 21?

September 10, 2024 by Dave Rowntree 35 Comments

IO user [monte] was pointed towards an 1898 display patent issued to a [George Mason] and liked the look of the ‘creepy’ font it defined. The layout used no less than 21 discrete segments to display the complete roman alphabet and numerals, which is definitely not possible with the mere seven segments we are all familiar with. [monte] then did the decent thing and created a demonstration digit using modern parts.

For the implementation, [monte] created a simple PCB by hand (with an obvious mistake) and 3D-printed an enclosure and diffuser to match. After a little debugging, a better PCB was ordered from one of the usual overseas factories. There isn’t a schematic yet, but they mention using a CH32V003 Risc-V micro, which can be seen sitting on the rear of the PCB.

Maximum flexibility is ensured by storing every glyph as a 32-bit integer, with each LED corresponding to a single bit. It’s interesting to note the display incorporates serifs, which are definitely optional, although you could display sans-serif style glyphs if you wanted to. There is now a bit of a job to work out how to map character codes to glyph codes, but you can have a go at that yourself here. It’s still early doors on this project, but it has some real potential for a unique-looking display.

We love displays—every kind. Here’s a layout reminiscent of a VFD digit but done purely mechanically. And if you must limit yourself to seven digits, what about this unique thing?

Continue reading “Why Have Seven Segments When You Can Have 21?” →

Mobile Coffee Table Uses Legs To Get Around

September 10, 2024 by Bryan Cockfield 22 Comments

For getting around on most surfaces, it’s hard to beat the utility of the wheel. Versatile, inexpensive, and able to be made from a wide array of materials has led to this being a cornerstone technology for the past ten thousand years or so. But with that much history it can seem a little bit played out. To change up the locomotion game, you might want to consider using robotic legs instead. That’s what [Giliam] designed into this mobile coffee table which uses custom linkages to move its legs and get itself from place to place around the living room.

Continue reading “Mobile Coffee Table Uses Legs To Get Around” →

Assessing The Energy Efficiency Of Programming Languages

September 10, 2024 by Maya Posch 66 Comments

Programming languages are generally defined as a more human-friendly way to program computers than using raw machine code. Within the realm of these languages there is a wide range of how close the programmer is allowed to get to the bare metal, which ultimately can affect the performance and efficiency of the application. One metric that has become more important over the years is that of energy efficiency, as datacenters keep growing along with their power demand. If picking one programming language over another saves even 1% of a datacenter’s electricity consumption, this could prove to be highly beneficial, assuming it weighs up against all other factors one would consider.

There have been some attempts over the years to put a number on the energy efficiency of specific programming languages, with a paper by Rui Pereira et al. from 2021 (preprint PDF) as published in Science of Computer Programming covering the running a couple of small benchmarks, measuring system power consumption and drawing conclusions based on this. When Hackaday covered the 2017 paper at the time, it was with the expected claim that C is the most efficient programming language, while of course scripting languages like JavaScript, Python and Lua trailed far behind.

With C being effectively high-level assembly code this is probably no surprise, but languages such as C++ and Ada should see no severe performance penalty over C due to their design, which is the part where this particular study begins to fall apart. So what is the truth and can we even capture ‘efficiency’ in a simple ranking?

Continue reading “Assessing The Energy Efficiency Of Programming Languages” →

Rescuing High-Res Displays From Older Macs

September 10, 2024 by Bryan Cockfield 26 Comments

When Apple started rolling out its Retina displays, it multiplied the amount of pixels compared to their standard, non-Retina displays by four. This increased pixel density while keeping the standard screen size — idea for those needing a lot of detail for their work. But, as is common with Apple, using these displays outside of the Apple ecosystem can be quite a challenge. Retina displays have been around for about a decade now, though, with some third-party hardware able to break them free of their cage. This post details how [Kevin] liberated the 5K display from a 2017 iMac for more general use with support for USB-C.

The first step was to find a used iMac for the right price, and then sell off most of its parts to recoup most of the initial cost. That brought the cost of the panel itself to about $250. The key to getting the display working without all of the Apple hardware is the R1811 driver board, which can be had for around $300. A new 156 watt power supply was added to the mix, and [Kevin] also put in a few extras like a USB cable extension and a latching push-button which kills the display’s power. Additionally, he attempted to get the original iMac speakers working with this setup too, but none of his attempts resulted in anything close to quality sound so he’s mostly abandoned that extra feature for now.

With that all buttoned up, he has a 27″ 5K display with USB-C input for around $650 which is quite a deal. The MacRumors thread that [Kevin] added his project to currently has around 1,700 posts about similar builds too, so it can be a wealth of information for all kinds of models. As Apple drops support for their older machines, these displays will become more and more common and projects like these can keep a lot of e-waste out of the landfill while also providing decent hardware at a bargain price. Don’t just look for iMacs and MacBooks though; there’s a similar process to use various iPad displays for other things as well.