The Onion Tau LiDAR Camera is a small, time-of-flight (ToF) based depth-sensing camera that looks and works a little like a USB webcam, but with a really big difference: frames from the Tau include 160 x 60 “pixels” of depth information as well as greyscale. This data is easily accessed via a Python API, and example scripts make it easy to get up and running quickly. The goal is to be an affordable and easy to use option for projects that could benefit from depth sensing.
When the Tau was announced on Crowd Supply, I immediately placed a pre-order for about $180. Since then, the folks at Onion were kind enough to send me a pre-production unit, and I’ve been playing around with the device to get an idea of how it acts, and to build an idea of what kind of projects it would be a good fit for. Here is what I’ve learned so far.
If you watch many espionage or terrorism movies set in the present day, there’s usually a scene where some government employee enhances a satellite image to show a clear picture of the main villain’s face. Do modern spy satellites have that kind of resolution? We don’t know, and if we did we couldn’t tell you anyway. But we do know that even with unclassified resolution, scientists are using satellite imagery and machine learning to count things like elephant populations.
When you think about it, it is a hard problem to count wildlife populations in their habitat. First, if you go in person you disturb the target animals. Even a drone is probably going to upset timid wildlife. Then there is the problem with trying to cover a large area and figuring out if the elephant you see today is the same one as one you saw yesterday. If you guess wrong you will either undercount or overcount.
The Oxford scientists counting elephants used the Worldview-3 satellite. It collects up to 680,000 square kilometers every day. You aren’t disturbing any of the observed creatures, and since each shot covers a huge swath of territory, your problem of double counting all but vanishes.
Normally, we think of lasers as pretty complex and fairly intimidating devices: big glass tubes filled with gas, carefully aligned mirrors, cooling water to keep the whole thing from melting itself, that sort of thing. Let’s not even get started on the black magic happening inside of a solid state laser. But as [Jay Bowles] shows in his latest Plasma Channel video, building a laser from scratch isn’t actually as difficult as you might think. Though it’s certainly not easy, either.
The transversely excited atmospheric (TEA) laser in question uses high voltage passed across a a pair of parallel electrodes to excite the nitrogen in the air at standard atmospheric pressure, so there’s no need for a tube and you don’t have to pull a vacuum. The setup shakes so many UV photons out of the nitrogen that it doesn’t even need any mirrors. In fact, you should be able to get almost all the parts for a TEA laser from the hardware store. For example, the hexagonal electrodes [Jay] ends up using are actually 8 mm hex keys with the ends cut off.
When Rocket Lab launched their first Electron booster in 2017, it was unlike anything that had ever flown before. The small commercially developed rocket was the first to use fully 3D printed main engines, and instead of pumping its propellants with traditional turbines, the vehicle used electric motors that jettisoned their depleted battery packs overboard during ascent to reduce weight. It even looked different than its peers, as rather than a metal fuselage, the Electron was built from a lightweight carbon composite which gave it a distinctive black color scheme.
Packing so many revolutionary technical advancements into a single vehicle was a risk, but Rocket Lab founder Peter Beck believed a technical shakeup was the only way to get ahead in an increasingly competitive market. While that first launch in 2017 didn’t make it to orbit, the next year, Rocket Lab could boast three successful flights. By the end of 2020, a total of fifteen Electron rockets had completed their missions, carrying payloads from both commercial customers and government agencies such as NASA, the United States Air Force, and DARPA.
Rocket Lab’s gambit paid off, and the company has greatly outpaced competitors such as Virgin Orbit, Astra, and Relativity. In fact Electron is now the second most active orbital booster in the United States, behind SpaceX’s Falcon 9. Considering their explosive growth, it’s only natural they’d want to maintain that momentum going forward. But even still, the recent announcement that the company will be developing a far larger rocket they call Neutron to fly by 2024 took many in the industry by surprise; especially since Peter Beck himself had previously said they would never build it.
When [Vitor Melon] found out there was a custom firmware (CFW) available for his Xiaomi Mijia M365 Pro electric scooter that would increase his top end speed, naturally he installed it. Who wouldn’t want a little more performance out their hardware? But while the new firmware got the scooter running even better than stock, he does have a cautionary tale for anyone who might decide to ride their Mijia a bit harder than the fine folks at Xiaomi may have intended.
Now to be clear, [Vitor] does not blame the CFW for the fact that he cooked the control board of his Mijia. At least, not technically. There was nothing necessarily wrong with the new code or the capabilities it unlocked, but when combined with his particular riding style, it simply pushed the system over the edge. The failure seems to have been triggered by his penchant for using the strongest possible regenerative breaking settings on the scooter combined with a considerably higher than expected velocity attained during a downhill run. Turns out that big 40 flashing on the display wasn’t his speed, but an error code indicating an overheat condition. Oops.
Results of the PCB repair.
After a long and embarrassing walk home with his scooter, complete with a passerby laughing at him, [Vitor] opened the case and quickly identified the problem. Not only had the some of the MOSFETs failed, but a trace on the PCB had been badly burned through. Judging by the discoloration elsewhere on the board, it looks like a few of its friends were about to join in the self-immolation protest as well.
After a brief consultation with his graybeard father, [Vitor] replaced the dead transistors with higher rated versions and then turned his attention to the damaged traces. A bit of wire and a generous helping of solder got the main rail back in one piece, and he touched up the areas where the PCB had blackened for good measure.
A quick test confirmed the relatively simple repairs got the scooter up and running, but how was he going to prevent it from happening again? Reinstalling the original firmware with its more conservative governor was clearly no longer an option after he’d tasted such dizzying speeds, so instead he needed to find out some way to keep the controller cooler. The answer ended up being to attach the MOSFETs to the controller’s aluminum enclosure using thermal pads. This allows them to dissipate far more heat, and should keep a similar failure from happening again. You might be wondering why the MOSFETs weren’t already mounted this way, but unfortunately only Xiaomi can explain that one.
The Space Shuttle Challenger disaster on January 28, 1986 was a life-altering event for many, ranging from people who had tuned in to watch the launch of a Space Shuttle with America’s first teacher onboard, to the countless people involved in the manufacturing, maintenance and launching of these complex spacecraft. Yet as traumatizing as this experience was, there was one group of people for whom their dire predictions and warnings to NASA became suddenly reality in the worst way possible.
This group consisted of engineers at Morton-Thiokol, responsible for components in the Shuttle’s solid rocket boosters (SRBs). They had warned against launching the Shuttle due to the very cold weather, fearing that the O-ring seals in the SRBs at these low temperatures would not be able to keep the SRB’s hot gases from destroying the SRB and the Shuttle along with it.
Allan McDonald was one of these engineers who did everything they could to stop the launch. Until his death on March 6th of 2021, the experiences surrounding the Challenger disaster led him to become an outspoken voice on the topic of ethical decision-making, as well as a famous example of making the right decision, no matter how difficult the circumstances.
There’s been a constant over the last few weeks’ news, thanks to Elon Musk we’re in another Bitcoin hype cycle. The cryptocurrency soared after the billionaire endorsed it, at one point coming close to $60k, before falling back to its current position at time of writing of around $47k. The usual tide of cryptocurrency enthusiasts high on their Kool-Aid hailed the dawn of their new tomorrow, while a fresh cesspool of cryptocurrency scam emails and social media posts lapped around the recesses of the Internet.
This Time It’s Different!
The worst phrase that anyone can normally say about a financial bubble is the dreaded phrase “This time it’s different“, but there is something different about this Bitcoin hype cycle. It’s usual to hear criticism of Bitcoin for its volatility or its sometime association with shady deals, but what’s different this time is that the primary criticism is of its environmental credentials. The Bitcoin network, we are told, uses more electricity than the Netherlands, more than Argentina, and in an age where global warming has started to exert an uncomfortable influence over our lives, we can’t afford such extravagance and the emissions associated with them.
Here at Hackaday we are more concerned with figures than arguments over the future of currency, so the angle we take away from it all lies with those power stats. How much energy does Argentina use, and is the claim about Bitcoin credible?
