Nerfnet Tunnels TCP/IP Over NRF24L01 Radios

December 4, 2020 by Tom Nardi 31 Comments

There’s an excellent chance you’ve already worked with the nRF24L01. These little modules are an easy and cheap way to shuffle data across a 2.4 GHz radio link at a respectable rate, making them great for remote control projects. But after seeing that others had experimenting with using these radios to transmit digital audio, [Andrew Rossignol] got to wondering if some software trickery could push the envelope even further.

The result is nerfnet, a Linux program that allows you to tunnel TCP/IP over a pair of nRF24L01 modules. The link appears as a virtual interface, meaning everything happens transparently as far as other programs are concerned. Anything that uses TCP/IP to communicate on Linux can take advantage of this low-cost link, albeit at speeds that most of us haven’t had to deal with in decades.

Though it’s not quite as bad as you might think. Latency is around 50 ms, and after some tweaks, [Andrew] has been able to squeeze almost 300 Kbps out of the link. That’s more than enough for terminal work, and some light audio and video streaming isn’t out of the question.

In terms of range, he was able to maintain a fairly reliable connection at a distance of up to 60 meters (200 feet) outdoors. It might not sound like much, but again, you’ve got to take the cost of these radios into account. If you’re looking to SSH into a Raspberry Pi weather station you’ve got in the backyard, a pair of these could get the job done for just a couple of bucks.

The blog post [Andrew] has put together explains the software in fantastic detail if you’re interested in the nuts and bolts of it all. But if you just want to play around with the idea, you just need to connect some nRF24L01 modules to a pair of Raspberry Pis with short SPI wires to cut down any interference, and follow the instructions. Ideally the radios would have external antennas, but it’s not strictly required.

We’ve seen these modules pushed into service as impromptu Bluetooth Low Energy transmitters in the past, but nothing quite like this. While the latency and bandwidth offered by this technique might seem antiquated to modern eyes, it could be the perfect dedicated communication channel for your sensors, smart devices, or home automation projects.

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PinePhone Gets 3D Printed Mechanical Keyboard

December 3, 2020 by Tom Nardi 9 Comments

Do you remember when smartphones had real physical keyboards? Working the command line on some remote machine over SSH was a breeze, and you could even knock out a few lines of code if you were so inclined. But these days you’ve either got to lug around an external keyboard, or suffer through pecking out a few words per minute on a piece of glass. Doesn’t sound much like progress to us.

By the looks of it, [James Williams] doesn’t think so either. He’s designed a physical keyboard add-on that snaps onto the back of the PinePhone to deliver a proper, albeit condensed, typing experience. This is no repurposed BlackBerry board either; he’s created a custom mechanical keyboard that manages to fold into an incredibly small size thanks to resin printed keycaps and Kailh low profile switches. Other than the hand-drawn legends, it’s probably not a stretch to say this is a better keyboard than what many people have on their actual computers.

In addition to the 3D printed frame and Kailh switches, there’s also an Arduino Pro Micro onboard to communicate with the phone. Rather than use USB, the keyboard is wired to the I2C accessory port on the rear of the PinePhone. It sounds like [James] needs a little more time to polish his QMK build before its ready to release, so you might want to wait a bit before you start printing off your own copy of the parts.

Those following along with the development of the PinePhone know there’s supposedly an official keyboard accessory in the works, but who wants to wait when we’re so close to mobile Linux nirvana? Besides, we doubt it will be nearly as pleasant to type on as the board [James] has put together.

NSF Releases Video Of Arecibo’s Final Moments

December 3, 2020 by Tom Nardi 82 Comments

Today the National Science Foundation released a pair of videos that document the collapse of the Arecibo Observatory with incredible detail. A wide shot, apparently taken from the Visitors Center, shows the 900 ton instrument platform breaking free and swinging on the remaining support cables until it smashes into the edge of the dish. The second clip, recorded by an airborne drone, is focused directly on the cables as they failed. Both can be seen in the video embedded below.

Together, they produce an invaluable visual record of what finally brought the iconic radio telescope down. As was predicted by engineers earlier in the month, the failure of another support cable on tower 4 triggered a chain reaction that brought the entire platform crashing down onto the 305 meter reflector. Footage from a drone observing the top of tower 4 shows that the entire sequence, from the first visual wire break to the remaining cables being torn from their mounts, only took five seconds. While some initially doubted the NSF’s determination that it was too dangerous to repair Arecibo, this footage seems to prove just how tenuous the structural integrity of the Observatory really was.

A drone captured the critical cable failure.

These videos will hopefully help investigators who still need to determine why the cables failed in the first place. The cable in August didn’t snap, it simply pulled lose from its mount. It was suspected that the cable may have been incorrectly installed, but as it was only a backup, the situation was not seen as critical. But when the second cable failed in November it was found to have snapped at just 60% of its minimum breaking strength.

This immediately called into question the condition of the remaining cables, and ultimately lead to the decision by the NSF to proceed with a controlled demolition of the Observatory that would preserve as much of the scientific equipment as possible. Unfortunately, the remaining cables didn’t last long enough to put that plan into action.

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Crossed Wires Crash Rockets

December 3, 2020 by Tom Nardi 69 Comments

On November 17th, a Vega rocket lifted off from French Guiana with its payload of two Earth observation satellites. The booster, coincidentally the 17th Vega to fly, performed perfectly: the solid-propellant rocket engines that make up its first three stages burned in succession. But soon after the fourth stage of the Vega ignited its liquid-fueled RD-843 engine, it became clear that something was very wrong. While telemetry showed the engine was operating as expected, the vehicle’s trajectory and acceleration started to deviate from the expected values.

There was no dramatic moment that would have indicated to the casual observer that the booster had failed. But by the time the mission clock had hit twelve minutes, there was no denying that the vehicle wasn’t going to make its intended orbit. While the live stream hosts continued extolling the virtues of the Vega rocket and the scientific payloads it carried, the screens behind them showed that the mission was doomed.

Displays behind the hosts clearly showed Vega wasn’t following the planned trajectory.

Unfortunately, there’s little room for error when it comes to spaceflight. Despite reaching a peak altitude of roughly 250 kilometers (155 miles), the Vega’s Attitude Vernier Upper Module (AVUM) failed to maintain the velocity and heading necessary to achieve orbit. Eventually the AVUM and the two satellites it carried came crashing back down to Earth, reportedly impacting an uninhabited area not far from where the third stage was expected to fall.

Although we’ve gotten a lot better at it, getting to space remains exceptionally difficult. It’s an inescapable reality that rockets will occasionally fail and their payloads will be lost. Yet the fact that Vega has had two failures in as many years is somewhat troubling, especially since the booster has only flown 17 missions so far. A success rate of 88% isn’t terrible, but it’s certainly on the lower end of the spectrum. For comparison, boosters such as the Soyuz, Falcon 9, and Atlas have success rates of 95% or higher.

Further failures could erode customer trust in the relatively new rocket, which has only been flying since 2012 and is facing stiff competition from commercial launch providers. If Vega is to become the European workhorse that operator Arianespace hopes, figuring out what went wrong on this launch and making sure it never happens again is of the utmost importance.

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Waveshare’s Pi CM3 Laptop Arrives A Bit Too Late

December 3, 2020 by Tom Nardi 20 Comments

The good news it that you can now buy a pretty decent laptop that’s based around the Raspberry Pi Compute Module (CM). The bad news is that it was conceived before anyone knew the interface was going to change for the new CM4, so it doesn’t have any of the features that would make it really interesting such as support for PCI-Express. Oh, and it costs $300.

Waveshare, the company that most of us know best as a purveyor of e-paper displays, also made some rather interesting design choices on their laptop. See that black pad under the keyboard? No, it’s not a trackpad. It’s just a decorative cover that you remove to access an LED matrix and GPIO connectors. Make no mistake, a laptop that features a GPIO breakout right on the front is definitely our jam. But the decision to install it in place of the trackpad, and then cover it with something that looks exactly like a trackpad, is honestly just bizarre. It might not be pretty, but the Pi 400 seemed to have solved this problem well enough without any confusion.

On the other hand, there seems to be a lot to like about this product. For one, it’s a very sleek machine that doesn’t have the boxy and somewhat juvenile look that seems so common in other commercial Pi laptops. We also like that Waveshare included a proper Ethernet jack, something that’s becoming increasingly rare even on “real” laptops. As [ETA PRIME] points out in the video after the break, the machine also has a crisp IPS display and a surprisingly responsive keyboard. Though the fact that it still has a “Windows” key borders on being offensive considering how much it costs.

But really, the biggest issue with this laptop is when it finally hit the market. If Waveshare had rushed this out when the CM3 was first introduced, it probably would have been a more impressive technical achievement. On the other hand, had they waited a bit longer they would have been able to design it around the far more capable CM4. As it stands, the product is stuck awkwardly in the middle.

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Exploring Turn Of The Century RAF Avionics

December 1, 2020 by Tom Nardi 25 Comments

The second hand market is a wonderful thing; you never know what you might find selling for pennies on the dollar simply because it’s a few years behind the curve. You might even be able to scrounge up some electronics pulled out of a military aircraft during its last refit. That seems to be how [Adrian Smith] got his hands on a Control Display Unit (CDU) originally installed in a Royal Air Force AgustaWestland AW101 “Merlin” helicopter. Not content to just toss it up on a shelf, he decided to take a look inside of the heavy-duty cockpit module and see if he couldn’t make some sense out of how it works.

Unsurprisingly, [Adrian] wasn’t able to find much information on this device on the public Internet. The military are kind of funny like that. But a close look at the burn-in on the CDU’s orange-on-black plasma display seems to indicate it had something to do with the helicopter’s communication systems. Interestingly, even if the device isn’t strictly functional when outside of the aircraft, it does have a pretty comprehensive self-test and diagnostic system on-board. As you can see in the video after the break, there were several menus and test functions he was able to mess around with once it was powered up on the bench.

With the case cracked open, [Adrian] found three separate PCBs in addition to the display and keyboard panel on the face of the CDU. The first board is likely responsible for communicating with the helicopter’s internal systems, as it features a MIL-STD-1553B interface module, UART chips, and several RS-232/RS-485 transceivers. The second PCB has a 32-bit AMD microcontroller and appears to serve as the keyboard and display controller, possibly also providing the on-board user interface. The last board looks to be the brains of the operation, with a 25 MHz Motorola 68EC020 CPU and 1Mb of flash.

All of the hardware inside the CDU is pretty generic, but that’s probably the point. [Adrian] theorizes that the device serves as something of a generic pilot interface module, and when installed in the Merlin, could take on various functions based on whatever software was loaded onto it. He’s found pictures online that seem to show as many as three identical CDUs in the cockpit, all presumably running a different system.

[Adrian] has uncovered some interesting diagnostic information being dumped to the CDU’s rear connectors, but he’s still a long way off from actually putting the device to any sort of practical use. If any Hackaday readers have some inside information on this sort of hardware, we’re sure like to hear about it.

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Wemo Smart Plug Gets Brain Transplant

December 1, 2020 by Tom Nardi 17 Comments

Like many modern smart home gadgets, Belkin’s Wemo brand of smart plugs has a tendency to phone home every time you turn on a lamp. [Gigawatts] wasn’t having it, so they figured out how to flash the device with OpenWRT and replicated its original functionality with a web interface. Unfortunately this stopped working after awhile, and rather than trying to diagnose the issue, it seemed the time would be better spent simplifying the whole thing.

As [Gigawatts] explains, there are actually two separate boards inside the Wemo plug. One holds the relay to do the high-voltage switching, and the other provides the control. They are linked with a three wire connector, making it exceptionally simple to swap out the original controller for something different. The connector supplies 5 V and ground, all you’ve got to do is pull the third wire high to flick the switch.

While the ESP8266 probably would have been the first choice for many a Hackaday reader, [Gigawatts] actually went with the Moteino, a low-power Arduino compatible board with integrated RFM69 transceiver. With an LED to indicate status and a few lines of code tweaked, the Moteino got this once WiFi-only smart plug speaking a new language.

There’s some debate over how effective smart plugs are from an energy efficiency standpoint, but even if this reborn Wemo doesn’t help [Gigawatts] save much power, at least it won’t be blabbing about everything to a third-party.