Lithophane Lamp Has Us Over The Moon

Lithophanes are artistic creations which rely on the varying thickness of a material that is then backlit to reveal an image. While these were often made in porcelain in the past, these days we have the benefit of 3D printing on our side. The principle can be deftly applied to everything from flat planes to spheres, with [Tiffany Lo] demonstrating a great application of the latter with her 3D printed moon lamp.

The basic concept is to take a 2D image of the lunar surface, and then use it to generate a height mapped sphere for 3D printing. When lit from within, the sphere will appear as per the surface of the moon. The sphere geometry was generated with the Lithophane Sphere Maker online tool combined with NASA data of the moon intended for computer graphics purposes. The sphere was then printed on a typical FDM printer before being assembled upon a base with LEDs inside for backlighting.

The result is an attractive moon lamp that both recalls the heavy rock that follows us in a tidally-locked orbit, and yet can be switched off at night to make it easier to sleep. Unfortunately, it’s impractical to turn off the shine from the real moon, and we suspect nobody is working on the problem.

We’ve seen other moon lamps before; they’re a great starting point because the moon’s greyscale tones work well as a lithograph. More advanced techniques are likely necessary for those eager to create lamps of the gas giants; if you’ve done so, be sure to drop us a line.

One Instruction To Rule Them All: C Compiler Emits Only MOV

How many instructions do you need to successfully compile C code? Let’s see, you’d need some jump instructions, some arithmetic functions, and — of course — move instructions, right? Turns out you only need the move instruction, which — on x86, at least — is Turing complete.

While the effort is a bit tongue-in-cheek, we have to admit that if you were trying to create your own CPU, this would make for a simple architecture and might have power or complexity advantages, so maybe someone will find a practical use for it after all. If you wanted a C compiler for a simple CPU, this wouldn’t require much to emulate at a byte-code level, either.

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Custom Macro Keyboard Looks Good In Wood

There’s more than one way to make a mechanical macro pad, and this wooden wonder represents one of our favorites. [Tauno Erik] had an old rubber dome rectangle keyboard lying around that still worked, but the poor thing was missing some of its caps. After salvaging the controller, [Tauno Erik] got to work on the tedious task of figuring out the mapping of the matrix, which was made easier with a Python script.

Almost every component of this beauty is wood, including the mounting plate and those thicc and lovely keycaps — their top layer is solid oak, and the bottom bit is birch plywood. In order to interface the ‘caps with the switches, [Tauno Erik] designed and printed connector pieces that sit inside the extra large keycaps and accept the stems of the key switches.

Speaking of switches, we’re not sure if [Tauno Erik] ended up using Cherry green switches, browns, or a mix of both (that would be interesting), but each one is mounted on a custom PCB along with a diode and a pull-up resistor. You can see more build pictures at [Tauno Erik]’s site, and stick around for a visual tour of the completed build after the break.

Wood is a great choice for keycaps, and we imagine they’ll only look better with age and use. A more common use for wood on a keyboard build is in surprisingly comfortable wrist rests.

Simple Probe Sniffs Out EMI

Unable to account for the strange glitches he was seeing on his DIY CNC router, [Daniël Van Den Berg]  wondered if his electronics might be suffering from some form of electromagnetic interference (EMI). So he did what any good hacker would do, and rummaged through the parts bin to build an impromptu EMI detector.

[Daniël] is quick to point out that he’s not an electrical engineer, and makes no guarantees about the accuracy of his tossed together gadget. But it does seem to work well enough in his testing that he’s able to identify particularly “noisy” electronic components, so it’s probably worth putting one together just to hear what your hardware is pumping into the environment.

The hardware here is very simple, [Daniël] just attached a coil of solid copper wire to one of the analog pins on an Arduino Nano with a resistor, and hung a speaker off of one of the digital pins. From there, it just took a few lines of code to read the voltage in the coil and convert that into a tone for the speaker. The basic idea is that a strong alternating magnetic field will set up voltage fluctuations in the coil large enough for the Arduino’s ADC to read.

If you’re looking for a bit more insight into what kind of interference your electronic creations might be putting out, [Alex Whittimore] gave a fantastic presentation during the 2020 Hackaday Remoticon about performing RF debugging using a cheap RTL-SDR dongle.

New Part Day: ESP32-WROOM-DA

We’re always interested in the latest from the world’s semiconductor industry here at Hackaday, but you might be forgiven for noticing something a little familiar about today’s offering from Espressif. The ESP32-WROOM-DA has more than a passing resemblance to the ESP32-WROOM dual-core-microcontroller-with-WiFi  module that we’ve seen on so many projects over the last few years because it’s a WROOM, but this one comes with a nifty trick to deliver better WiFi connectivity.

The clever WiFi trick comes in the form of a pair of antennas at 90 degrees to each other. It’s a miniaturised version of the arrangement with which you might be familiar from home routers, allowing the device to select whichever antenna gives the best signal at any one time.

We can see that the larger antenna footprint will require some thought in PCB design, but otherwise the module has the same pinout as the existing WROVER. It’s not much of a stretch to imagine it nestled in the corner of a board at 45 degrees, and we’re sure that we’ll see it appearing in projects directly. Anything that enhances the connectivity of what has become the go-to wireless microcontroller on these pages can only be a good thing.

Retrotechtacular: Double For Nothing

If you are in the market for web hosting in 2021 and you sign up with one of the cloud computing providers, you’ll soon see how the different resources are priced. Storage and bandwidth are cheap, while CPU time is expensive. This reflects the state of a modern computer, in which a typical disk drive now holds a terabyte or more and rising by the year while a new processor is becoming a bottleneck whose performance hasn’t increased as much as the manufacturers would like over models from years ago.

Twice As Much Hardware From A Bit Of Software?

In the early 1990s though it was a different matter. A 486 or early Pentium processor was pretty powerful compared to the DOS or Windows 3.1 software it was expected to run, and it was the memory and disk space attached to it that limited performance… and cost an arm and a leg. There was a period in about 1995 when a supposed fire in a chip factory somewhere sent RAM prices into the hundreds of dollars per megabyte, briefly causing an epidemic of RAM raiding in which criminals would break into offices and take only the SIMs from the computers.

A solution to this problem came perhaps surprisingly from the software industry. Disk Doubler was a DOS driver that promised more disk space, achieving this seemingly impossible feat by compressing the disk to fit more data on it. Processor power swapped for disk space was a reasonable trade at the time so it became extremely popular, and eventually Microsoft incorporated their own disk compression into DOS. In some cases it could even speed up a computer with a slow disk drive, as I found out as a student with a 286 packing an MFM drive.

Something For Nothing, Perhaps It’s Too Good To Be True.

If compression could increase disk space then couldn’t it do the same for RAM? The industry came to the rescue once more with an array of RAM doubler products, first applying the disk doubling technique to on-disk virtual memory, and then doing the same with the contents of the memory itself. The first approach worked at the expense of a system slow-down, while the second, not so much. In fact it was little more than a scam, with software products promising much but delivering absolutely nothing behind the scenes.

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Hackaday Podcast 119: Random Robot Writing, Slithering Snake Shenanigans, And Phased Array Phenomena

Hackaday editors Mike Szczys and Elliot Williams pick up on the neatest hacks you may have missed. We start off with another “What’s that Sound?” so put your geeky-ears to the test and win a Hackaday Podcast T-shirt. Here are a couple of classic hacks to bring you joy: music based on Markov chains, and a squiggly take on the classic Nokia game of snake. For the more hardcore science geeks we dive into the B Meson news coming out of CERN’s physics experiments. And after taking a detour in bristle-bot-based pen plotting, we unpack the hidden system of pipes that carry oil, gas, diesel, and more from the refinery to your region.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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