Hackaday Podcast Episode 353: Fantastic Peripherals, Fake Or Not Fake Picos, And Everything On The Steam Deck

Join Hackaday Editors Elliot Williams and Tom Nardi as they swap their favorite hacks and stories from the week. In this episode, they’ll start off by marveling over the evolution of the “smart knob” and other open hardware input devices, then discuss a futuristic propulsion technology you can demo in your own kitchen sink, and a cheap handheld game system that get’s a new lease on life thanks to the latest version of the ESP32 microcontroller.

From there they’ll cover spinning CRTs, creating custom GUIs on Android, and yet another thing you can build of out that old Ender 3 collecting dust in the basement. The episode wraps up with a discussion about putting Valve’s Steam Deck to work and a look at the history-making medical evacuation of the International Space Station.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

As always, this episode is available in DRM-free MP3.

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Trying Out The Allwinner-Based Walnut Pi SBC

When it comes to the term ‘Raspberry Pi clones’, the most that they really clone is the form factor, as nobody is creating clones of Broadcom VideoCore-based SoCs. At least not if they want to stay safe from Broadcom’s vicious legal team. That said, the Walnut Pi 1B single-board computer (SBC) that [Silly Workshop] recently took a gander at seems to be taking a fairly typical approach to a Raspberry Pi 4 form factor compatible board.

Part of Walnut Pi’s line-up, the Allwinner H616/H168-equipped 1B feels like it takes hints from both the RPi 4B and the Asus Tinkerboard, especially with its nicely colored GPIO pins. There’s also a beefier Walnut Pi 2B with an Allwinner T527 SoC that’s not being reviewed here. Translating the Chinese-language documentation for the board suggests that either the H616 or H618 may be installed, with both featuring a quad-core Cortex-A53, so in the ballpark of the Raspberry Pi 3.

There are also multiple RAM configurations, ranging from 1 GB of DDR3 to 4 GB of LPDDR4, with the 1 GB version being fun to try and run benchmarks like GeekBench on. Ultimately the impression was that it’s just another Allwinner SoC-based board, with a half-hearted ‘custom’ Linux image, no hardware acceleration due to missing (proprietary) Allwinner IP block drivers, etc.

While cheaper than a Raspberry Pi SBC, if you need anything more than the basic Allwinner H61* support and Ethernet/WiFi, there clearly are better options, some of which may even involve repurposing an e-waste Android TV box.

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Optimizing Software With Zero-Copy And Other Techniques

An important aspect in software engineering is the ability to distinguish between premature, unnecessary, and necessary optimizations. A strong case can be made that the initial design benefits massively from optimizations that prevent well-known issues later on, while unnecessary optimizations are those simply do not make any significant difference either way. Meanwhile ‘premature’ optimizations are harder to define, with Knuth’s often quoted-out-of-context statement about these being ‘the root of all evil’ causing significant confusion.

We can find Donald Knuth’s full quote deep in the 1974 article Structured Programming with go to Statements, which at the time was a contentious optimization topic. On page 268, along with the cited quote, we see that it’s a reference to making presumed optimizations without understanding their effect, and without a clear picture of which parts of the program really take up most processing time. Definitely sound advice.

And unlike back in the 1970s we have today many easy ways to analyze application performance and to quantize bottlenecks. This makes it rather inexcusable to spend more time today vilifying the goto statement than to optimize one’s code with simple techniques like zero-copy and binary message formats.

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WCH CH32M030: Another Microcontroller To Watch Out For

One of the joys of writing for Hackaday comes in following the world of new semiconductor devices, spotting interesting ones while they are still just entries on manufacturer websites, and then waiting for commonly-available dev boards. With Chinese parts there’s always a period in which Chinese manufacturers and nobody else has them, and then they quietly appear on AliExpress.

All of which brings us to the WCH CH32M030, a chip that’s been on the radar for a while and has finally broken cover. It’s the CH32 RISC-V microcontroller you may be familiar with, but with a set of four half-bridge drivers on board for running motors. A handy, cheap, and very smart motor controller, if you will.

There’s been at  least one Chinese CH32M030 dev board (Chinese language) online for a while now, but the one listed on AliExpress appears to be a different design. At the time of writing the most popular one is still showing fewer than 20 sales, so we’re getting in at the ground floor here.

We think this chip is of interest because it has the potential to be used in low price robotic projects, replacing as it does a couple of parts or modules in one go. If you use it, we’d like to hear from you!

A PSOne In The Palm Of Your Hand

Sony’s original Playstation wasn’t huge, and they did shrink it for re-release later as the PSOne, but even that wasn’t small enough for [Secret Hobbyist]. You may have seen the teaser video a while back where his palm-size Playstation went viral, but now he’s begun a series of videos on how he redesigned the vintage console.

Luckily for [Secret Hobbyist], the late-revision PSOne he started with is only a two-layer PCB, which made reverse engineering the traces a lot easier. Between probing everything under the microscope and cleaning the board off to follow all the traces in copper, [Hobbyist] was able to reproduce the circuit in KiCAD. (Reverse engineering starts at about 1:18 in the vid.)

With a schematic in hand, drafting a smaller PCB than Sony built is made easier by the availability of multi-layer PCBs. In this case [Hobbyist] was able to get away with a four-layer board. He was also able to ditch one of the ICs from the donor mainboard, which he called a “sub-CPU” as its functionality was recreated on the “PSIO” board that’s replacing the original optical drive. The PSIO is a commercial product that has been around for years now, allowing Playstations to run from SD cards– but it’s not meant for the PSOne so just getting it working here is something of a hack. He’s also added on a new DAC for VGA output, but otherwise the silicon is all original SONY.

This is the first of a series about this build, so if you’re into retro consoles you might want to keep an eye on [Secret Hobbyist] on YouTube to learn all the details as they are released.

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What Happens When A Bug Rears Its Head At Mach Two?

While some may see amateur rocketry as little more than attaching fins to a motor and letting it fly, it is, in fact, rocket science. This fact became very clear to [BPS.space] when a parachute deployed on a rocket traveling at approximately Mach 1.8. 

The rocket design is rather simple — essentially just 3D printed fins glued onto a motor with a nose-cone for avionics. A single servo and trim tab provide a modicum of roll control, and a parachute is mounted in the nose along with a homing beacon for faster recovery. Seemingly, the only thing different about this flight is properly validated telemetry and GPS antennae.

After a final ground check of the telemetry and GPS signal quality, everything is ready for what seems like a routine launch. However, somewhere around Mach 1.8, the parachute prematurely deploys, ripping apart the Kevlar rope holding together the three rocket sections. Fortunately, the booster and avionics sections could be recovered from the desert.

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A red-and-blue image of a nebula is shown, shaped somewhat like an eye, with a plume of gas emitting from the center.

Is The Theory Of Special Relativity Wrong?

There’s an adage coined by [Ian Betteridge] that any headline ending in a question mark can be answered by the word “No”. However, Lorentz invariance – the theory that the same rules of physics apply in the same way in all frames of reference, and an essential component of special relativity – has been questioned for some time by researchers trying to unify general relativity and quantum field theory into a theory of quantum gravity. Many theories of quantum gravity break Lorentz invariance by giving photons with different energy levels very slightly different speeds of light – a prediction which now looks less likely since researchers recently analyzed gamma ray data from pulsed astronomical sources, and found no evidence of speed variation (open-access paper).

The researchers specifically looked for the invariance violations predicted by the Standard-Model Extension (SME), an effective field theory that unifies special relativity with the Standard Model. The variations in light speed which it predicts are too small to measure directly, so instead, the researchers analyzed gamma ray flare data collected from pulsars, active galactic nuclei, and gamma-ray bursts (only sources that emitted gamma rays in simultaneous pulses could be used). Over such great distances as these photons had traveled, even slight differences in speed between photons with different energy levels should have added up to a detectable delay between photons, but none was found.

This work doesn’t disprove the SME, but it does place stricter bounds on the Lorentz invariance violations it allows, about one and a half orders of magnitude stricter than those previously found. This study also provides a method for new experimental data to be more easily integrated into the SME. Fair warning to anyone reading the paper: the authors call their work “straightforward,” from which we can only conclude that the word takes on a new meaning after a few years studying mathematics.

If you want to catch up on relativity and Lorentz invariance, check out this quick refresher, or this somewhat mind-bending explanation. For an amateur, it’s easier to prove general relativity than special relativity.


Top image: Crab Pulsar, one of the gamma ray sources analysed. (Credit: J. Hester et al., NASA/HST/ASU/J)