Storing Image Data As Analog Audio

February 12, 2026 by No comments

Ham radio operators may be familiar with slow-scan television (SSTV) where an image is sent out over the airwaves to be received, decoded, and displayed on a computer monitor by other radio operators. It’s a niche mode that isn’t as popular as modern digital modes like FT8, but it still has its proponents. SSTV isn’t only confined to the radio, though. [BLANCHARD Jordan] used this encoding method to store digital images on a cassette tape in a custom-built tape deck for future playback and viewing.

The self-contained device first uses an ESP32 and its associated camera module to take a picture, with a screen that shows the current view of the camera as the picture is being taken. In this way it’s fairly similar to any semi-modern digital camera. From there, though, it starts to diverge from a typical digital camera. The digital image is converted first to analog and then stored as audio on a standard cassette tape, which is included in the module in lieu of something like an SD card.

To view the saved images, the tape is played back and the audio signal captured by an RP2040. It employs a number of methods to ensure that the reconstructed image is faithful to the original, but the final image displays the classic SSTV look that these images tend to have as a result of the analog media. As a bonus feature, the camera can use a serial connection to another computer to offload this final processing step.

We’ve been seeing a number of digital-to-analog projects lately, and whether that’s as a result of nostalgia for the 80s and 90s, as pushback against an increasingly invasive digital world, or simply an ongoing trend in the maker space, we’re here for it. Some of our favorites are this tape deck that streams from a Bluetooth source, applying that classic cassette sound, and this musical instrument which uses a cassette tape to generate all of its sounds.

Exploring Homebrew For The Pokémon Mini

February 12, 2026 by No comments

Originally only sold at the Pokémon Center New York in late 2001 for (inflation adjusted) $80, the Pokémon Mini would go on to see a release in Japan and Europe, but never had more than ten games produced for it. Rather than Game Boy-like titles, these were distinct mini games that came on similarly diminutive cartridges. These days it’s barely remembered, but it can readily be used for homebrew titles, as [Inkbox] demonstrates in a recent video.

Inside the device is an Epson-manufactured 16-bit S1C88 processor that runs at 4 MHz and handles basically everything, including video output to the monochrome 96×64 pixel display. System RAM is 4 kB of SRAM, which is enough for the basic games that it was designed for.

The little handheld system offered up some capabilities that even the full-sized Game Boy couldn’t match, such as a basic motion sensor in the form of a reed relay. There’s also 2 MB of ROM space directly addressable without banking.

Programming the device is quite straightforward, not only because of the very accessible ISA, but also the readily available documentation and toolchain. This enables development in C, but in the video assembly is used for the added challenge.

Making the screen tiles can be done in an online editor that [Inkbox] also made, and the game tested in an emulator prior to creating a custom cartridge that uses an RP2040-based board to play the game on real hardware. Although a fairly obscure gaming handheld, it seems like a delightful little system to tinker with and make more games for.

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The Death Of Baseload And Similar Grid Tropes

February 12, 2026 by 5 Comments

Anyone who has spent any amount of time in or near people who are really interested in energy policies will have heard proclamations such as that ‘baseload is dead’ and the sorting of energy sources by parameters like their levelized cost of energy (LCoE) and merit order. Another thing that one may have noticed here is that this is also an area where debates and arguments can get pretty heated.

The confusing thing is that depending on where you look, you will find wildly different claims. This raises many questions, not only about where the actual truth lies, but also about the fundamentals. Within a statement such as that ‘baseload is dead’ there lie a lot of unanswered questions, such as what baseload actually is, and why it has to die.

Upon exploring these topics we quickly drown in terms like ‘load-following’ and ‘dispatchable power’, all of which are part of a healthy grid, but which to the average person sound as logical and easy to follow as a discussion on stock trading, with a similar level of mysticism. Let’s fix that.

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Bash Via Transpiler

February 12, 2026 by 2 Comments

It is no secret that we often use and abuse bash to write things that ought to be in a different language. But bash does have its attractions. In the modern world, it is practically everywhere. It can also be very expressive, but perhaps hard to read.

We’ve talked about Amber before, a language that is made to be easier to read and write, but transpiles to bash so it can run anywhere. The FOSDEM 2026 conference featured a paper by [Daniele Scasciafratte] that shows how to best use Amber. If you prefer slides to a video, you can read a copy of the presentation.

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Practice Makes Perfect: The Wet Dress Rehearsal

February 12, 2026 by 5 Comments

If you’ve been even casually following NASA’s return to the Moon, you’re likely aware of the recent Wet Dress Rehearsal (WDR) for the Artemis II mission. You probably also heard that things didn’t go quite to plan: although the test was ultimately completed and the towering Space Launch System (SLS) rocket was fully loaded with propellant, a persistent liquid hydrogen leak and a few other incidental issues lead the space agency to delay further testing for at least a month while engineers make adjustments to the vehicle.

This constitutes a minor disappointment for fans of spaceflight, but when you’re strapping four astronauts onto more than five million pounds of propellants, there’s no such thing as being too cautious. In fact, there’s a school of thought that says if a WDR doesn’t shake loose some gremlins, you probably weren’t trying hard enough. Simulations and estimates only get you so far, the real thing is always more complex, and there’s bound to be something you didn’t account for ahead of time.

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Correlating Electric Cars With Better Air Quality

February 12, 2026 by 44 Comments

Although at its face the results seem obvious, a recent study by [Sandrah Eckel] et al. on the impact of electric cars in California is interesting from a quantitative perspective. What percentage of ICE-only cars do you need to replace with either full electric or hybrid cars before you start seeing an improvement in air quality?

A key part of the study was the use of the TROPOMI instrument, part of the European Sentinel-5 Precursor satellite. This can measure trace gases and aerosols in the atmosphere, both of which directly correlate with air quality. The researchers used historical TROPOMI data from 2019 to 2023 in the study, combining this data with vehicle registrations in California and accounting for confounding factors, such as a certain pandemic grinding things to a halt in 2020 and massively improving air quality.

Although establishing direct causality is hard using only this observational data, the researchers did show that the addition of 200 electric vehicles would seem to be correlated to an approximate 1.1% drop in measured atmospheric NO2. This nitrogen oxide is poisonous and fatal if inhaled in large quantities. It’s also one of the pollutants that result from combustion, when at high temperatures nitrogen from the air combines with oxygen molecules. Continue reading “Correlating Electric Cars With Better Air Quality” →

Making Effective, Affordable Water Level Monitors

February 12, 2026 by 25 Comments

Water wells are simple things, but that doesn’t mean they are maintenance-free. It can be important to monitor water levels in a well, and that gets complicated when the well is remote. Commercial solutions exist, of course, but tend to be expensive and even impractical in some cases. That’s where [Hans Gaensbauer]’s low-cost, buoyancy-based well monitor comes in. An Engineers Without Border project, it not only cleverly measures water level in a simple way — logging to a text file on a USB stick in the process — but it’s so low-power that a single battery can run it for years.

The steel cable (bottom left) is attached to a submerged length of pipe, and inside the cylinder is a custom load cell. The lower the water level, the higher the apparent weight of the submerged pipe.

The monitor [Hans] designed works in the following way: suspend a length of pipe inside the well, and attach that pipe to a load cell. The apparent weight of the pipe will be directly proportional to how much of the pipe is above water. The fuller the well, the less the pipe will seem to weigh. It’s very clever, requires nothing to be in the well that isn’t already water-safe, and was designed so that the electronics sit outside in a weatherproof enclosure. Cost comes out to about $25 each, which compares pretty favorably to the $1000+ range of industrial sensors.

The concept is clever, but it took more that that to create a workable solution. For one thing, space was an issue. The entire well cap was only six inches in diameter, most of which was already occupied. [Hans] figured he had only about an inch to work with, but he made it work by designing a custom load cell out of a piece of aluminum with four strain gauges bonded to it. The resulting sensor is narrow, and sits within a nylon and PTFE tube that mounts vertically to the top of the well cap. Out from the bottom comes a steel cable that attaches to the submerged tube, and out the top comes a cable that brings the signals to the rest of the electronics in a separate enclosure. More details on the well monitor are in the project’s GitHub repository.

All one has to do after it’s installed is swap out the USB stick to retrieve readings, and every once in a long while change the battery. It sure beats taking manual sensor readings constantly, like meteorologists did back in WWII.