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Comment Re:Model Airplanes/Rockets (Score 1) 533

Ease of use.

Even the shittiest toy quadcopters have self stabilising geometry, and only slightly more expensive ones have active stabilising electronics. A lot of them have fan shrouds and can take a few bumps and crashes without incident. The barrier for entry is very low and the potential for misuse is high.

By comparison, most RC helicopters end up as a pile of twisted metal and shattered carbon about 10 seconds after their launch. RC aircraft would also end up in the dirt pretty quickly, but usually just broke a prop or something. If you managed to keep them in the air, they require constant high levels of attention that is just not sustainable for long. The learning curve required encouraged people to join clubs and get proper training on how to be a safe and responsible flier.

Comment Re:Like twisted-pair cable? (Score 2) 186

It's similar but almost completely unlike the twisting in twisted pair.

A normal toroidal tokomak has the magnets closer together and the centre than at the outside, and the variation in the resulting magnetic field leads to instabilities. The twist in the stellerator is supposed to ensure that the variations in magnetic field all get cancelled out as the plasma circulates.

Comment Taylor Swift had it right. (Score 1) 190

Haters gonna hate....

I don't see why people are criticizing the Pi Zero so much, I can only assume they lack imagination. If you need to buy the extra peripherals then maybe a full size Pi is a better choice, but that doesn't mean there's not a valid use for the Pi Zero.

For example:
- Training labs where the the peripherals can be re-used, but if someone fries a board it's only a $5 replacement instead of $35.
- Portable/mobile projects where USB WiFi is sufficient.
- Standalone, embedded projects that require a little more grunt than an Arduino - eg image recognition using a USB webcam.

The fact that the Pi Zero exists only helps the community, and having a little extra choice is a great thing. I think it's freaking awesome.

Comment Re:Ignorance (Score 1) 190

I've got about a 10 micro-pc and embedded projects around the house.

Five of those projects use an arduino (usually a nano) because that's all they require. They are cheap, reliable and dead easy to program.

The remaining five use RPI's. Three of those are small headless servers (file server, zoneminder and squid proxy), so they need Ethernet for the performance. The fourth is an OctoPi 3D Print Server, it only needs USB Serial and USB Wifi. The last one is a Brew Plant controller running a webserver, it's on a mobile platform inside a sealed box so uses USB Wifi too (and the GPIO).

So out of ten projects, two of those could have used a much cheaper PI Zero with absolutely no loss in functionality or utility, and the reduction in size would have been an advantage. Every project has a different set of requirements, sometimes there is overlap between products and sometimes it is clear. One thing is for sure though, there is definitely a use case for the Pi Zero,

Comment Re:except they don't. Voltage of 120 batteries (Score 2) 209

The charging comment is only true up to a point. As you get larger solid packs, the surface area doesn't increase as fast as the volume and the insides can get very hot. Thermal management is super critical for many battery types so this is a major limitation.

With a small cylindrical battery, the empty packing space between the cells provides a perfect channel for cooling.

Comment Re:How does space elevator save energy? (Score 4, Insightful) 171

The person you heard that from was wrong.

In a rocket,:
- Rockets are quite inefficient, about 16% energy efficient to reach orbit.
- You have to lift your propellant, only to throw it all away
- The rocket not only has to do work against gravitational potential, it also has to provide lateral kinetic energy to reach orbit. The kinetic energy component is huge.

For a space elevator:
- The lifting motors are highly efficient, you just have to keep the power beaming losses reasonable.
- You only have to work against gravitational potential. The tether/earth provides the lateral kinetic energy.

Comment Re: non-story (Score 1) 199

There are degrees of off/standby. It's good engineering practice and environmentally that when you "soft" power down, you turn off as many internal circuits as you are able and only retain basic functionality required to turn back on again.

LED off
Camera sensor off completely
WiFi chip in low power / periodic transmit mode
CPU at lower clock speed or sleep mode with periodic wake up timer.

Not doing this means that the camera designers were either:
1) Lazy and unprofessional
2) Planning to retain the camera functionality for nefarious uses.

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