WWII Hydrogen Peroxide Rocket 3D Print

August 17, 2021 by Al Williams 37 Comments

[Integza] was reading about a World War II-era rocket plane created near the end of the war by the Germans. The Heinkel He-176 wasn’t very practical, but he was intrigued when he read the rocket was cold and combustionless. He did a little research and found the engine was a monopropellent engine using hydrogen peroxide. This led to some interesting experiments and a 3D printed rocket engine, as you can see in the video below.

Usually, liquid-fueled rocket engines have a fuel and an oxidizer that mix and are either ignited or, in a hypergolic rocket, spontaneously combust on contact. With a monopropellent, the thrust comes from a chemical reaction between the propellant — hydrogen peroxide, in this case, and a catalyst.

Continue reading “WWII Hydrogen Peroxide Rocket 3D Print” →

Take Note: An E-Paper Tablet From Pine64

August 17, 2021 by Jenny List 20 Comments

Over the years we’ve seen a variety of interesting pieces of hardware emerging from the folks at Pine64, so it’s always worth a second look when they announce a new product. This time it’s the PineNote, a tablet that packs the same Rockchip RK3566 as used in the company’s Quartz64 single board computers behind a 10.1″ 1404 x 1872 16-tone greyscale e-paper screen.

Fitted with 4 GB of LPDDR4 RAM and 128 GB eMMC flash storage, it will feature the same Linux support as previous Pine64 products, with the slight snag of the display driver not yet being complete for 5.xx kernels. They are thus at pains to point out that this is not a ready-to-go consumer device and that early adopters will be expected to write code rather than notes on it.

That last sentence sums up Pine64’s offering perfectly, they produce interesting hardware with open-source support, but sometimes the path from hardware release to stable and usable product can be a rocky one. If you’re interested in hardcore hacking of an e-paper tablet, then you may want to be an early adopter. Otherwise, hang back for a while and buy one once some of the bugs have been ironed out. Meanwhile you can see the whole update in the video below; it has a few other things including a nifty keyboard for the PinePhone.

We’ve mentioned Pine64 a few times over the years, it’s worth noting that their products also lie outside the realm of Linux boxen.

Continue reading “Take Note: An E-Paper Tablet From Pine64” →

Retrotechtacular: Amiga Pips The PC For Mission-Critical Computing At NASA

August 16, 2021 by Chris Wilkinson 46 Comments

In 1986, a group of NASA engineers faced a difficult choice in solving their data processing woes: continue tolerating the poor performance of PC architecture, or pony up the cash for exotic workstations. It turns out that the Commodore Amiga was an intriguing third choice, except for the fact that, paradoxically, it didn’t cost enough. Oh, and Apple wanted nothing to do with any of it.

Steeped in history, NASA’s Hangar AE is a hub for launch vehicle telemetry and other mission communications, primarily during prelaunch phases for launches at Cape Canaveral. Throughout the late 20th century, Hangar AE supported NASA launch vehicles in all shapes and sizes, from the Atlas-Centaur evolutions to the mighty Titan family. It even supported user data from the Space Shuttle program. Telemetry from these missions was processed at Hangar AE before being sent out to other NASA boffins, and even transmitted worldwide to other participating space agencies.

Coming down from decades of astronomical levels of funding, the 1980s was all about tightening the belt, and NASA needed budget solutions that didn’t skimp on mission safety. The Commodore Amiga turned out to be the right choice for processing launch vehicle telemetry. And so it was still, when cameras from the Amiga Atlanta group were granted permission to film inside Hangar AE.

Continue reading “Retrotechtacular: Amiga Pips The PC For Mission-Critical Computing At NASA” →

Tesla Automatic Driving Under Scrutiny By US Regulators

August 16, 2021 by Al Williams 66 Comments

The US National Highway Traffic Safety Administration (NHTSA) has opened a formal investigation about Tesla’s automatic driving features (PDF), claiming to have identified 11 accidents that are of concern. In particular, they are looking at the feature Tesla calls “Autopilot” or traffic-aware cruise control” while approaching stopped responder vehicles like fire trucks or ambulances. According to the statement from NHTSA, most of the cases were at night and also involved warning devices such as cones, flashing lights, or a sign with an arrow that, you would presume, would have made a human driver cautious.

There are no details about the severity of those accidents. In the events being studied, the NHTSA reports that vehicles using the traffic-aware cruise control “encountered first responder scenes and subsequently struck one or more vehicles involved with those scenes.”

Despite how they have marketed the features, Tesla will tell you that none of their vehicles are truly self-driving and that the driver must maintain control. That’s assuming a lot, even if you ignore the fact that some Tesla owners have gone to great lengths to bypass the need to have a driver in control. Tesla has promised full automation for driving and is testing that feature, but as of the time of writing the company still indicates active driver supervision is necessary when using existing “Full Self-Driving” features.

We’ve talked a lot about self-driving car safety in the past. We’ve also covered some of the more public accidents we’ve heard about. What do you think? Are self-driving cars as close to reality as they’d like you to believe? Let us know what you think in the comments.

DIY Handheld Game Puts Its Brains On A Removable Cart

August 16, 2021 by Tom Nardi 10 Comments

Over the years we’ve seen plenty of homebrew handheld game systems that combine an AVR microcontroller, a few buttons, and an small OLED display. Some of them have even been turned into commercial products, such as the Arduboy. They’re simple, cheap, and with the right software, a lot of fun. But being based on an MCU, most of them share the same limitation of only being able to hold a single game at any one time.

But not the Game Card, by [Dylan Turner]. This handheld was specifically designed so that games could be easily swapped out using physical cartridges. But rather than trying to get the system’s microcontroller to boot code from an external flash chip, the system relocates the MCU to the removable cartridge. That might seem a bit overkill, but given how cheap the ATTINY84A on each cartridge is, it’s not exactly going to break the bank.

With the microcontroller on the cartridge, the only hardware that stays behind on the Game Card is the SSD1306 128×64 OLED display, buttons, and the battery. That means the handheld is effectively non-functional unless a game is slotted in, but that could be said of most early cartridge-based game systems as well. On the other hand, it also opens up the possibility of producing cartridges with more powerful microcontrollers down the line.

Using a different microcontroller for each game is a neat hack, but it’s not the only solution to the problem. We previously saw a community effort to add expandable storage to the Arduboy in the form of a DIY cartridge, which ultimately led to the development of an official flash chip upgrade for the handheld.

Continue reading “DIY Handheld Game Puts Its Brains On A Removable Cart” →

New Part Day: Raspberry Pi HAT For IEEE1588 Precision Time Protocol

August 16, 2021 by Dave Rowntree 18 Comments

The new Real-Time HAT by InnoRoute adds IEEE1588 PTP support in hardware to a Raspberry Pi 4 nestled beneath. Based around a Xilinx Artix-7 FPGA and a handful of gigabit Ethernet PHY devices, the HAT acts as network-passthrough, adding accurate time-stamps to egress (outgoing) packets and stripping time-stamps from the ingress (incoming) side.

This hardware time-stamping involves re-writing Ethernet packets on-the-fly using specialised network hardware which the Raspberry Pi does not have. Yes, there are software-only 1588 stacks, but they can only get down to 10s of microsecond resolutions, unlike a hardware approach which can get down to 10s of nanoseconds.

1588 is used heavily for applications such as telecoms infrastructure, factory equipment control and anything requiring synchronisation of data-consuming or data-producing devices. CERN makes very heavy use of 1588 for its enormous arrays of sensors and control equipment, for all the LHC experiments. This is the WhiteRabbit System, presumably named after the time-obsessed white rabbit of Alice In Wonderland fame. So, if you have a large installation and a need for precisely controlling when stuff happens across it, this may be just the thing you’re looking for.

IEEE1588 PTP Synchronisation

The PTP client and master device ping a few messages back and forth between themselves, with the network time-stamper recording the precise moment a packet crosses the interface. These time-stamps are recorded with the local clock. This is important. From these measurements, the time-of-flight of the packet and offset of the local clock from the remote clock may be calculated and corrected for. In this way each client node (the hat) in the network will have the same idea of current time, and hence all network packets flowing through the whole network can be synchronised.

The beauty of the system is that the network switches, wiring and all that common infrastructure don’t need to speak 1588 nor have any other special features, they just need to pass along the packets, ideally with a consistent delay.

The Real-Time HAT configures its FPGA via SPI, straight from Raspberry Pi OS, with multiple applications possible, just by a change on the command line. It is possible to upload custom bitstreams, allowing the HAT to be used as a general purpose FPGA dev board should you wish to do so. It even stacks with the official PoE HAT, which makes it even more useful for hanging sensors on the end of a single wire.

Of course, if your needs are somewhat simpler and smaller in scale than a Swiss city, you could just hack a GPS clock source into a Raspberry Pi with a little soldering and call it a day.

Voice-Controlled Smart Home From The Foundation Up

August 16, 2021 by Bryan Cockfield 20 Comments

Smart homes are becoming an increasingly popular way to automate one’s home, whether it’s turning on lights, closing blinds, or even feeding pets. But the commercial offerings often rely on an internet connection to reach servers in order to work, which invites a lot of privacy concerns for a large percentage of us as well as being inconvenient when the internet is down. Essentially the only way to have a privacy-respecting, self-sufficient smart home is to build one on your own from the ground up, which is exactly what [Xasin] has done with this project.

This build is based on ESP32 modules with a Raspberry Pi as a hub, but it’s not as simple as a MQTT implementation. Not only does the self-contained home automation setup not rely on any outside services, but a failure of the central Pi server will not impact the nodes either as they are configured to continue operating independently even without central control. This allows for a robust home automation implementation without a single point of failure, and also includes some other features that are helpful as well including voice control, all while retaining a core design philosophy that makes it relatively easy to build.

Not only is the build technologically impressive for its standalone capabilities and its elimination of privacy concerns, but [Xasin] also did an excellent job with the physical design as well, adding plenty of RGB and a hexagonal enclosure that gives it a unique look wherever its is placed. If you’re renting right now or otherwise unable to interface any automation with your current home, be sure to take a look at some projects that do home automation without making any permanent changes.

Continue reading “Voice-Controlled Smart Home From The Foundation Up” →