Hackaday Links: May 30, 2021

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That collective “Phew!” you heard this week was probably everyone on the Mars Ingenuity helicopter team letting out a sigh of relief while watching telemetry from the sixth and somewhat shaky flight of the UAV above Jezero crater. With Ingenuity now in an “operations demonstration” phase, the sixth flight was to stretch the limits of what the craft can do and learn how it can be used to scout out potential sites to explore for its robot buddy on the surface, Perseverance.

While the aircraft was performing its 150 m move to the southwest, the stream from the downward-looking navigation camera dropped a single frame. By itself, that wouldn’t have been so bad, but the glitch caused subsequent frames to come in with the wrong timestamps. This apparently confused the hell out of the flight controller, which commanded some pretty dramatic moves in the roll and pitch axes — up to 20° off normal. Thankfully, the flight controller was designed to handle just such an anomaly, and the aircraft was able to land safely within five meters of its planned touchdown. As pilots say, any landing you can walk away from is a good landing, so we’ll chalk this one up as a win for the Ingenuity team, who we’re sure are busily writing code to prevent this from happening again.

If wobbling UAVs on another planet aren’t enough cringe for you, how about a blind mechanical demi-ostrich drunk-walking up and down a flight of stairs? The work comes from the Oregon State University and Agility Robotics, and the robot in question is called Cassie, an autonomous bipedal bot with a curious, bird-like gait. Without cameras or lidar for this test, the robot relied on proprioception, which detects the angle of joints and the feedback from motors when the robot touches a solid surface. And for ten tries up and down the stairs, Cassie did pretty well — she only failed twice, with only one counting as a face-plant, if indeed she had a face. We noticed that the robot often did that little move where you misjudge the step and land with the instep of your foot hanging over the tread; that one always has us grabbing for the handrail, but Cassie was able to power through it every time. The paper describing how Cassie was trained is pretty interesting — too bad ED-209’s designers couldn’t have read it.

So this is what it has come to: NVIDIA is now purposely crippling its flagship GPU cards to make them less attractive to cryptocurrency miners. The LHR, or “Lite Hash Rate” cards include new-manufactured GeForce RTX 3080, 3070, and 3060 Ti cards, which will now have reduced Ethereum hash rates baked into the chip from the factory. When we first heard about this a few months ago, we puzzled a bit — why would a GPU card manufacturer care how its cards are used, especially if they’re selling a ton of them. But it makes sense that NVIDIA would like to protect their brand with their core demographic — gamers — and having miners snarf up all the cards and leaving none for gamers is probably a bad practice. So while it makes sense, we’ll have to wait and see how the semi-lobotomized cards are received by the market, and how the changes impact other non-standard uses for them, like weather modeling and genetic analysis.

Speaking of crypto, we found it interesting that police in the UK accidentally found a Bitcoin mine this week while searching for an illegal cannabis growing operation. It turns out that something that uses a lot of electricity, gives off a lot of heat, and has people going in and out of a small storage unit at all hours of the day and night usually is a cannabis farm, but in this case it turned out to be about 100 Antminer S9s set up on janky looking shelves. The whole rig was confiscated and hauled away; while Bitcoin mining is not illegal in the UK, stealing the electricity to run the mine is, which the miners allegedly did.

And finally, we have no idea what useful purpose this information serves, but we do know that it’s vitally important to relate to our dear readers that yellow LEDs change color when immersed in liquid nitrogen. There’s obviously some deep principle of quantum mechanics at play here, and we’re sure someone will adequately explain it in the comments. But for now, it’s just a super interesting phenomenon that has us keen to buy some liquid nitrogen to try out. Or maybe dry ice — that’s a lot easier to source.

19 thoughts on “Hackaday Links: May 30, 2021

    1. I have seen InGaN blue LEDs turn UV and AlInGaP green LEDs turn red when both were chilled to LN2 temperatures. I don’t really have any understanding why the bandgap (and thus photon period) wouldn’t always decrease as in the Shockley diode equation…

  1. I wonder if those crippled cards would be uncrippled once the next generation is for sale, so that those using the cards for things other than mining can sell them for mining in order to buy new cards for their own use?

    1. Unlikely. Nvidia is doing this so those cards will never be attractive to miners, if you could just flip a switch, miners would figure that out and do it from the beginning (which defeats the purpose).

    2. Nvidia is crippling the gaming cards as it wants to sell miners their mining-specific cards, which are not usable for gaming, eliminating that part of the secondary market for used mining cards.
      Removing a source of second hand cards on the market plays into nvidias profit margins while giving them good prf for “preserving the gaming GPU’s for gamers”.

    1. The issue is sending the videos back to earth. It’s not like they can just grab the SD card. They may eventually get better videos downloaded, but initially they get smaller samples.

  2. > Any landing you walk away from is a good landing.

    Sometimes they add: “Any landing where you can use the plane again is a great landing”.

    I would say that “great landings” is then the only goal for the mars-helicopter. There’s a bolt that came loose, just send a mechanic to tighten it please!

  3. I remember hearing, and this may no longer be true, that LN2 was about the same price as milk.
    The university where I studied had a couple of research MRI machines, so to assure a constant supply of liquid nitrogen, and helium, they had a small gas- liquefacation plant out the back, and because air is ~78% nitrogen, there was literally buckets of it spare. As undergrads we got up to all sorts of mischief with it. Shame we never thought of putting LED’s in it though.
    (The uni also covered some of the costs by selling various bottled gases from the plant).

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