Lisp In 99 Lines Of C With TinyLisp

August 19, 2025 by Maya Posch 13 Comments

As one of the oldest programming languages still in common use today, and essential for the first wave of Artificial Intelligence research during the 1950s and 60s, Lisp is often the focus of interpreters that can run on very low-powered systems. Such is the case with [Robert van Engelen]’s TinyLisp, which only takes 99 lines of C code and happily runs on the Z80-based Sharp PC-G850V(S) pocket computer with its 2.3 kB of internal RAM and native C support.

The full details on how TinyLisp was implemented and how to write it yourself can be found in the detailed article that’s part of the GitHub project. It supports static scoping, double-precision floating point and features 21 Lisp primitives along with a garbage collector. Two versions for the Sharp PC-G850 (using BCD (i.e. NaN) boxing) are provided, along with a number of generic implementations, using either double or single precision floating point types. A heavily commented version is probably the version to keep alongside the article while reading.

TinyLisp is – as the name implies – very tiny, and thus more full-featured Lisp implementations are widely available. This includes two versions – linked at the bottom of the Readme – also by [Robert] that use a gargantuan 1,000 lines of C, providing a more advanced garbage collector and dozens more Lisp primitives to handle things like exceptions, file loading, strings and debug features.

Volkswagen Joins The Car-As-A-Service Movement With Its ID.3 BEV

August 19, 2025 by Maya Posch 113 Comments

More and more car manufacturers these days are becoming interested in the recurring revenue model, with Volkswagen’s ID.3 BEV being the latest to have an optional ‘motor power upgrade’ that you can pay for either monthly or with a ‘lifetime’ payment.

As the BBC reports, this option is now available in the UK, with customers offered the option to pay £16.50 per month or £165 annually, or opt to shell out £649 for what is reportedly a ‘car lifetime’ subscription.

It appears that this subscription service has been in the works for a while already, with it being offered first last year in countries like Denmark, following which it appears to be rolled out in other countries too. The software unlock changes the maximum motor output from 150 kW to 170 kW, which some users report as being noticeable.

Regardless of whether you find this to be a good deal, the concept of Car-As-A-Service (CAAS) has becoming increasingly prevalent, with the BBC article referencing BMW’s heated seats subscription and Mercedes’ acceleration subscription. Considering that all the hardware is already in the car that you purportedly purchased, this is sure to rub people the wrong way, not to mention that from a car tuning perspective this seems to suggest that third-party tuners don’t need to apply.

Thanks to [Robert Piston] for the tip.

The Terminal Demise Of Consumer Electronics Through Subscription Services

August 18, 2025 by Maya Posch 86 Comments

Open any consumer electronics catalog from around the 1980s to the early 2000s and you are overwhelmed by a smörgåsbord of devices, covering any audio-visual and similar entertainment and hobby needs one might have. Depending on the era you can find the camcorders, point-and-shoot film and digital cameras right next to portable music players, cellphones, HiFi sets and tower components, televisions and devices like DVD players and VCRs, all of them in a dizzying amount of brands, shapes and colors that are sure to fit anyone’s needs, desires and budget.

When by the late 2000s cellphones began to absorb more and more of the features of these devices alongside much improved cellular Internet access, these newly minted ‘smartphones’ were hailed as a technological revolution that combined so many consumer electronics into a single device. Unlike the relatively niche feature phones, smartphones absolutely took off.

Fast-forward more than a decade and the same catalogs now feature black rectangles identified respectively as smart phones, smart TVs and tablets, alongside evenly colored geometric shapes that identify as smart speakers and other devices. While previously the onus for this change was laid by this author primarily on the death of industrial design, the elephant in the room would seem to be that consumer electronics are suffering from a terminal disease: subscription services.

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Practical Guide To Pedal-Powered Electrical Generators

August 17, 2025 by Maya Posch 51 Comments

An adult human can produce about 100 Wh of mechanical power whilst cycling, which is a not inconsiderable amount if you can convert that to electricity with reasonable efficiency. In a recent article on EDN [T. K. Hareendran] goes over a few ways that you can turn the rotary motion of pedaling into usable electrical power.

Suggested voltage regulator for pedal-powered generator. (Credit: T. K. Hareendran, EDN)

A basic form of this is already widely deployed, in the form of a bicycle dynamo that is used to supply power to the front and rear lights. These typically put out something like 3 watts at 6 VAC, so with a simple bridge rectifier and some smoothing this can power a pretty bright LED or two. To get more out of it, you need to use a more capable generator, which can also be a brushed or brushless DC motor in a pinch, with ideally a flywheel in the whole contraption to balance out variations in the human power input.

As for the potential here, a commercial solution like the K-Tor Power Box 50 is specified for ‘greater than’ 50 Watt, with a nominal 12 VDC output. Its target market is emergency generators, with enough capability to keep phones, radios and flashlights charged. Considering the $435 asking price, there is probably quite a lot of DIY potential well within that price bracket, especially if you already have many of the requisite parts lying around.

Fortunately this is not a new idea, with us having covered using bicycles as well as gym equipment to generate electricity in the past.

Commodore Is Back Selling New C64s, But Should You Buy Them?

August 17, 2025 by Maya Posch 108 Comments

It’s hard to argue with nostalgia, but you can toss a bucket of cold facts over it. In the case of the recent rescuing of the Commodore brand from the clutches of relabeling of generic electronics by [Perifractic] of Retro Recipes, we got [The Retro Shack] doing the proverbial bucket dumping in a new video. Basically the question is whether the fresh Commodore 64 offerings by the new-and-improved Commodore are what you really want, or need.

The thing is that over the decades many people have created all the bits that you need to build your own classical C64, or even buy one off-the-shelf, with people like [bwack] having reverse-engineered the various C64 mainboards. These can be populated with drop-in replacements for chips like the SID, VIC-II, CIAs and others that are readily available, along with replica cases and keyboards. If you crave something less bulky and complex, you can run a bare metal C64 emulator like BMC64 on a Raspberry Pi, or just run the VICE emulator on your platform of choice. There’re also options like the full-sized TheC64 and Ultimate 64 Elite II systems that you can buy ready to go.

Basically, there is a whole gamut of ways to get some part of the C64 experience, ranging from emulator-only to a full hardware DIY or pre-assembled format. Each of which come with their own price tag, starting at $0 for running VICE on your existing system. With so much choice we can only hope that the renewed Commodore company will become something more than Yet Another C64 Experience.

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MorPhlex: The TPU Filament That Goes Soft After You Print It

August 16, 2025 by Maya Posch 7 Comments

In FDM 3D printing cycles TPU is a bit of a special filament. Not so much because of its properties, but because it’s rather stretchy even as a filament, which makes especially printing certain hardness grades of TPU into somewhat of an nightmare. An interesting new contender here comes from a company called BIQU, who reckon that their ‘MorPhlex’ TPU solves many of those problems. Recently the [ModBot] channel on YouTube got sent a spool of the filament for testing.

The BIQU MorPhlex TPU filament being turned into squishy slippers. (Credit: ModBot, YouTube)

The ‘magic’ here is that this TPU claims to be a 90A TPU grade while on the spool, but after printing it becomes 75A, meaning a lot softer and squishier. Perhaps unsurprisingly, a big selling point on their product page is that you can print squishy shoes with it. Beyond this is claims to be compatible with ‘most FDM printers’, and the listed printing parameters are typical for TPU in terms of extruder and bed temperature.

After drying the filament as recommended for TPU in general, test prints were printed on a Bambu Lab H2D. Here BIQU recommends not using the AMS, but rather the dedicated TPU feeding channel. For the test prints some slippers were printed over the course of two days. In hindsight glue stick should have been applied to make parts removal easier.

The slippers were indeed squishy, but the real test came in the form of a Shore A hardness meter and some test cube prints. This showed an 80 – 85A for the BIQU MorPhlex test cube depending on whether to test the side or top. As the product datasheet indicates a final hardness of 75A +/- 3A, one could argue that it’s kind-of in spec, but it mostly raises questions on how parameters like temperature and extrusion speed affect the final result.

2003 Samsung CD player playing a clear vs normal audio CD. (Credit: Adrian's Digital Basement)

Why Lorde’s Clear CD Has So Many Playback Issues

August 15, 2025 by Maya Posch 72 Comments

Despite the regularly proclaimed death of physical media, new audio albums are still being published on CD and vinyl. There’s something particularly interesting about Lorde’s new album Virgin however — the CD is a completely clear disc. Unfortunately there have been many reports of folks struggling to get the unique disc to actually play, and some sharp-eyed commentators have noted that the CD doesn’t claim to be Red Book compliant by the absence of the Compact CD logo.

The clear Lorde audio CD in all its clear glory. (Credit: Adrian's Digital Basement, YouTube) — The clear Lorde audio CD in all its clear glory. (Credit: Adrian’s Digital Basement, YouTube)

To see what CD players see, [Adrian] of Adrian’s Digital Basement got out some tools and multiple CD players to dig into the issue. These players range from a 2003 Samsung, a 1987 NEC, and a cheap portable Coby player. But as all audio CDs are supposed to adhere to the Red Book standard, a 2025 CD should play just as happily on a 1980s CD player as vice versa.

The first step in testing was to identify the laser pickup (RF) signal test point on the PCB of each respective player. With this hooked up to a capable oscilloscope, you can begin to see the eye pattern forming. In addition to being useful with tuning the CD player, it’s also an indication of the signal quality that the rest of the CD player has to work with. Incidentally, this is also a factor when it comes to CD-R compatibility.

While the NEC player was happy with regular and CD-R discs, its laser pickup failed to get any solid signal off the clear Lorde disc. With the much newer Samsung player (see top image), the clear CD does play, but as the oscilloscope shot shows, it only barely gets a usable signal from the pickup. Likewise, the very generic Coby player also plays the audio CD, which indicates that any somewhat modern CD player with its generally much stronger laser and automatic gain control ought to be able to play it.

That said, it seems that very little of the laser’s light actually makes it back to the pickup’s sensor, which means that along with the gain the laser output gets probably cranked up to 11, and with that its remaining lifespan will be significantly shortened. Ergo it’s probably best to just burn that CD-R copy of the album and listen to that instead.

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