I've seen the video where all these methods were tried to no avail, so I don't have much faith in them. The safest solution is to put the animal down, but of course you have to have something on hand to do that. A 4x2 to the temple should do it. That'll end the aggressor and save the victim.
"Should", maybe, but I've seen a pretty disturbing video where a pit bull took a lot more than one hit... it was multiple minutes of hits. And it only let go after it died, I've never seen anything like it.
The power connectors will be on the far side of the rack from the service side so shouldn’t be a problem for humans touching the third rail so to speak.
With that sort of voltage you should be able to use a capacitive or inductive sensor to activate a relay.
Obviously the contact point in the sled will need to be disconnected while not grounded, as the top level suggested, or shorted to ground across a large resistor. It’s not the amperage that’s going to cause problems it’s the 800 volts, backed by the amperage. Small enough capacitance and large enough ground load should let you tap in without frying anything including air.
Wouldn’t the biggest problem will be loading sleds into a hot rack, with all of the sleds powered down? Which probably you shouldn’t do. The parallel loads on a rack that’s half on should sink a lot of the potential.
IMO, there are more steps. Do what you love for work, someone will exploit you for it, and break your heart.
One of my kids has taken this advice, does art (really good art) for themselves and is pursuing a STEM career instead. The other is pursuing a game dev career, despite every current and former dev in his life warning him off for the last fifteen years. To quote Kissing Jessica Stein, “OY! This child will suffer.”
Back in the day, I was a fairly good artist[0]. I was good enough to get work, and pursue a career, although I don’t know how successful I would have been.
Fortunately, I also really enjoyed tech, and figured that even a mediocre programmer would do better than a top-shelf fantasy artist. Back then (hard to believe, these days), competition was a lot less prevalent, in tech, and was brutal, in art.
Off the cuff, the first step to ASLR is don’t publish your images and to rotate your snapshots regularly.
The old fastCGI trick is to buffer the forking by idling a half a dozen or ten copies of the process and initialize new instances in the background while the existing pool is servicing new requests. By my count we are reinventing fastCGI for at least the fourth time.
Long running tasks are less sensitive to the startup delays because we care a lot about a 4 second task taking an extra five seconds and we care much less about a 1 minute task taking 1:05. It amortizes out even in Little’s Law.
These systems make it more efficient to remove the actively toxic members for your team. Beligerence can be passively aggressively “handled” by additional layers but at considerable time and emotional labor cost to people who could be getting more work done without having to coddle untalented assholes.
There's no such thing as a hiring process that avoids that problem 100% of the time.
After all, most people will be on their best behavior during an interview, and even a lengthy interview process is a very short period of time compared to working with someone for weeks or months.
I learned recently that the inductive heating coils used for metallurgy (smithing) are copper tubing with coolant flushing through them. The copper tries to heat up along with the bar you’re heating in the coil. Both from resistance and from radiative heating.
Eight months ago he built a quadrupedal robot that could step sideways using three of them per leg. I’m not going to link that, you’ll have to find it from his YouTube page because you should look around.
Sorry for going off topic. "Electric Motor Scaling Laws and Inertia in Robot Actuators" by Ben Katz who designed the MIT Mini Cheetah in 2018 is very well known in the legged robotics community. His master’s thesis on actuator design is also widely referenced.
During the COVID period, some Chinese companies even sold variants of actuators inspired by the Mini Cheetah design.
Aaed Musa has also mentioned in some of his videos that his actuator designs were inspired by the Mini Cheetah actuator. Yes, His capstan drive video is especially impressive.
For example, in Aaed Musa’s video "I Built a Rubik's Cube Solving Robot" (https://www.youtube.com/watch?v=m0bMMALYMYk), he states in the description that the design was inspired by Ben Katz’s work.
I did a bit of a deep dive into motor control and actuators in building a two axis gimbal for tracking satellites with an RF antenna (with the eventual goal of building a mount for optical tracking).
Ben's vids were kind of mind-blowing for me at that time. I couldn't believe some of the control that was possible with relatively pedestrian electronics. Aaed's vids do a wonderful job of making it accessible in an applied way.
It's something I think a lot of the folks on HN would find interesting to tinker with. Nice mix of software and hardware that actually does work in physical reality. It also gives me a level of appreciation for the advances in humanoid robots that I don't think I would have had otherwise. (If you *do* get into it, I'd highly recommend getting into field oriented control with brushless motors and encoders. Small hobby servos are fun but they encapsulate a lot of the interesting parts and tend to have limited options available for things like the capstan vid linked above)
Thanks for this. I almost never have the patience for any videos, but this one hooked me and kept me engaged throughout. Worth it for that random "yo mama" joke alone.
This channel about retrofitting industrial robotic arm control systems is quite practical. Could always run the playback at 1.25 speed for slow talkers/edits =3
If you pay attention to Smarter Every Day videos he’s occasionally in the background, which makes me suspect he’s still active but doing behind the scenes stuff and less in his garage.
I hate the phrase "zero backlash" that gets used right in the intro. Nothing has zero backlash. If it did, that would mean the material is incompressible & unstretchable: it would have an infinite speed of sound. You could implement FTL communication using zero-backlash actuators. Capstan drives have backlash because the rope stretches. It's very low if using a low-stretch rope, but nonzero.
Backlash & a lack of stiffness have the same effect, but the cause happens at different scales. Just because the gaps are in between the atoms of the dyneema doesn't mean there are no gaps! There's still play due to a lack of stiffness, just less of it. The positioning errors should be lower than the feedback resolution on the servo encoders, but they won't be zero.
I disagree; backlash is unrelated to force. If you were to graph error over force for backlash it would be a straight line but for something like dyneema it would directly scale with force applied.
In a driven system the dead zone is graphable and that deadzone time or area does not change based on velocity, A lack of rigidity in couplings, gears or belts IS affected by velocity
Dyneema has remarkably low elongation, in addition to its very high strength to weigh ratio. Higher than Kevlar (but less heat resistant). It’s why they used it for sail cloth before rigid body sails took over most competition sailing.
Aaed I believe is preloading his devices, which should eliminate most of the remaining give but also increase wear rate. Though it sounds like from the video that the biggest problem is rubbing the cord against itself, hence the channels to guide the cords.
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