Pumped hydro storage is one of the oldest grid storage technologies, and one of the most widely deployed, too. The concept is simple – use excess energy to pump a lot of water up high, then run it back through a turbine when you want to get the energy back later.
With the rise in renewable energy deployments around the world, there is much interest in finding ways to store energy from these often-intermittent sources. Traditional pumped hydro can help, but there is only so much suitable land to work with.
However, there could be a solution, and it lurks deep under the waves. Yes, we’re talking about underwater pumped hydro storage!
When it comes to building decent aerodynamic devices, you want to focus on getting your geometry accurate, and making sure your parts are strong enough to deal with the force they’re generating. This build from [Engineering After Hours] delivers on those fronts, consisting of a high-downforce wing for a small RC car.
The video points out that, at best, even a decent RC car will have pretty crappy aerodynamic parts from the factory, with a lift-to-drag (L/D)ratio of 2-3:1 at best. This means that, while they may create some small amount of downforce, they’re also creating plenty of drag at the same time.
The dual-element wing designed here is much more efficient, hitting an L/D ratio in the vicinity of 17:1 – a huge improvement. Even a casual eye can note that the design looks a lot more like something you’d see on a full-size car, versus some of the whackier designs seen on toys.
The wing is built with a forged carbon fiber process using 3D-printed molds, to give the wing plenty of strength. Given that it’s built for an RC car that can do over 100 mph, making sure the wing is stiff enough to perform at speed is key.
[Engineering After Hours] does a great job of showing how to prepare the molds, fill them with carbon fiber, and pour the resin, and discusses plenty of useful tips on how to achieve good results with the forged carbon process.
The result is an incredibly impressive rear wing with aerodynamic performance to match its good looks. It may be more complicated than 3D printing, but the results of the work are that much tougher.
We cover a lot of cyberdeck projects here at Hackaday, custom portable computers often built around the Raspberry Pi. It’s not often that we cover a computer that perfectly achieves and exceeds what a cyberdeck is trying to do without being a cyberdeck in any way, but that’s what [Subir Bhaduri] has done. In addressing the need for Indian schoolchildren to catch up on two years of COVID-disrupted schooling he’s created the pπ, a Raspberry Pi, projector, and keyboard all-in-one computer in a neat sheet-metal case that looks as though it might be just another set of spanners or similar. At a stroke he’s effortlessly achieved the ultimate cyberdeck, because this machine is no sci-fi prop, instead it has a defined use which it fulfills admirably.
All the files to build your own can be found in a GitLab repository. The case is laser-cut sheet metal, and he’s put in a cost breakdown which comes out at a relatively healthy 17200 Indian rupees, or around 230 US dollars. We hope that it serves its purpose well and provides a rugged and reliable teaching aid for a generation from whom COVID has taken so much. You can see more in the video below the break.
Sometimes reverse engineering embedded systems can be a right old faff, with you needing to resort to all kinds of tricks such as power glitching in order to poke a tiny hole in the armour, giving you an way in. And, sometimes the door is just plain wide open. This detailed exploration of an off-the-shelf retro arcade machine, is definitely in that second camp, for an unknown reason. [Matthew Alt] of VoidStar Security, took a detailed look into how this unit works, which reads as a great introduction to how embedded Linux is constructed on these minimal systems.
Could this debug serial port be more obvious?
The hardware is the usual bartop cabinet, with dual controls and an LCD display, with just enough inside a metal enclosure to drive the show. Inside this, the main PCB has the expected minimal ARM-based application processor with its supporting circuit. The processor is the Rockchip RK3128, sporting a quad-core ARM Neon and a Mali400 GPU, but the main selling point is the excellent Linux support. You’ll likely see this chip or its relatives powering cheap Android TV boxes, and it’s the core of this nice looking ‘mini PC’ platform from firefly. Maybe something to consider seeing as though Raspberry Pis are currently so hard to come by?
Anyway, we digress a little, [Matthew] breaks it down for us in a very methodical way, first by identifying the main ICs and downloading the appropriate datasheets. Next he moves on to connectors, locating an internal non-user-facing USB micro port, which is definitely going to be of interest. Finally, the rather obvious un-populated 3-pin header is clearly identified as a serial port. This was captured using a Saleae clone, to verify it indeed was a UART interface and measure the baud rate. After doing that, he hooked it into a Raspberry Pi UART and by attaching the standard screen utility to the serial device, lo-and-behold, a boot log and a root prompt! This thing really is barn-door wide-open.
Is that a root prompt you have for me? Oh why yes it is!
Simply by plugging in a USB stick, the entire flash memory was copied over, partitions and all, giving a full backup in case subsequent hacking messed things up. Being based on U-Boot, it was a trivial matter of just keying in ‘Ctrl-C’ at boot time, and he was dropped straight into the U-Boot command line, and all configuration could be easily read out. By using U-Boot to low-level dump the SPI flash to an external USB device, via a RAM copy, he proved he could do the reverse and write the same image back to flash without breaking something, so it was now possible to reverse engineer the software, make changes and write it back. Automation of the process was done using Depthcharge on the Raspberry Pi, which was also good to read about. We will keep an eye on the blog for what he does with it next!
The average home kettle is set up to switch off automatically when water reaches its boiling point. But would a kettle filled with alcohol, which has a significantly lower boiling point, actually turn off? [Steve Mould] set out to find out.
The prediction was that a kettle full of 40% strength vodka would boil dry, as the vodka would evaporate before it actually got to a hot enough temperature to cause the kettle’s cutout mechanism to kick in. The experiment was done outside to minimise the dangers from the ethanol vapor. As it turns out, the vapor from the boiling vodka is about 80% ethanol and just 20% water, so eventually the mixture left in the kettle is mostly water and it boils hot enough to trigger the cutout mechanism.
However, the experiment doesn’t end there. Trying again with 99% ethanol, when the fluid started boiling, the kettle switched off even more quickly. So what’s going on?
The kettle in question uses a bimetallic strip, which trips the switch off in the base of the kettle when it gets too hot. There’s also a tube inside the kettle that carries vapor from the internal cavity and lets it pass over the bimetallic strip. When the liquid inside the kettle boils, it forces hot vapor through the tube, out of the kettle and over the bimetallic strip.
This strip triggers at a temperature significantly lower than the boiling point of water; indeed, as long as the liquid in the kettle is fairly hot and is boiling enough to force vapor out the tube, the kettle will switch off. [Steve] points out that it’s a good mechanism, as this mechanism allows the kettle to respond to boiling itself, rather than the arbitrary 100 C point which water technically only boils at when one is at sea level.
Oftentimes, when programming, we’ll put configuration switches into a config file in order to control the behaviour of our code. However, having to regularly open a text editor to make changes can be a pain. This colorful little DIP switch dongle from [Glen Aikins] makes for a fun alternative solution.
Do want.
The build is simple, relying on a rainbow-colored 8-pin DIP switch as the core of the project. A PIC16F1459 then reads the position of the switches, with the 8-bit microcontroller doing the job of speaking USB to the host machine. The device enumerates as a USB HID device, and reports to the host machine when queried as to the state of its 8 switches. [Glen] used a basic C# app to show a digital representation of the switches on screen changing as per the real physical DIP switch plugged into the machine.
It’s a great tool for controlling up to 8 different parameters in a program you might be working on, without having to dive into your editor to change the relevant parts. Also, it bears noting that the rainbow design is simply very fetching and a cool thing to have plugged into your computer. It’s a more serious device than [Glen’s] hilarious 4-byte “solid state drive” that we saw recently, but we love them both all the same!
Older Apple computers can often be something of a collector’s item, with the oldest fetching an enormously high price in auctions. The ones from the late ’80s and early ’90s don’t sell for quite as much yet, but it’s possible that museums and collectors of the future will one day be clamoring for those as well. For that reason, it’s generally frowned upon to hack or modify original hardware. Luckily, this replica of an Apple Macintosh didn’t harm any original hardware yet still manages to run software on bare metal.
The computer is built around a single-board computer, but this SBC isn’t like the modern ARM machines that have become so ubiquitous. It’s a 133MHz AMD 486 which means that it can run FreeDOS and all of the classic DOS PC games of that era without emulation. In order to run Apple’s legacy operating system, however, it does require the use of the vMac emulator, but the 486 is quite capable of handling the extra layer of abstraction. The computer also sports a real SoundBlaster ISA sound card, uses a microSD card for its hard drive, and uses an 800×600 LCD screen.
As a replica, this computer is remarkably faithful to the original and even though it doesn’t ship with a Motorola 68000 it’s still fun to find retro PC gamers that are able to run their games on original hardware rather than emulation. It reminds us of another retro 486 that is capable of running old games on new hardware without an emulator as well.
The video points out that, at best, even a decent RC car will have pretty crappy aerodynamic parts from the factory, with a lift-to-drag (L/D)ratio of 2-3:1 at best. This means that, while they may create some small amount of downforce, they’re also creating plenty of drag at the same time.
