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Comment: Bitscope Micro (Score 1) 172

by ColaMan (#47226449) Attached to: Ask Slashdot: PC-Based Oscilloscopes On a Microbudget?

Bitscope Micro - USB , 40MS/s, USD95 in quantities of 10 or more.

Fairly decent set of software tools for it (including a basic FFT spectrum analyser and a protocol decoder that can do UART / SPI / Canbus.) Software runs on windows/linux and Raspberry Pi - You can download the software and tinker with a few bitscopes that are online to get a feel for it.

Specs here

Comment: Re: SpaceX always have an excuse for failure (Score 4, Informative) 110

by ColaMan (#46886821) Attached to: SpaceX Looking For Help With "Landing" Video

You seem a little harsh on them.

Recovery of the booster would have been nice for investigation, but it was never intended to be flown again and was never the stated goal. The goal for that mission was a controlled descent and touch down on the ocean, which they accomplished. A 'soft-recover' wasn't the term that they were using.

This goal needed to be reached so that Range Safety at the launch pad can determine that SpaceX can reliably put a rocket down within a mile or so of a target. The next launch - in the next week or so - will attempt to land in the ocean much closer to the launch facility.

The technical difficulties of a soft landing are considerable given the hardware that they've got. With the weight of the empty booster, they can't throttle the engines back far enough to hover. So they fall towards the surface and at the right moment fire the engines to reach a computed zero velocity at touchdown. Doing this with gusty 30-40 knot winds on the surface is tough. 'Landing' on a continuously-undulating surface where there is no consistent level is tougher.

And yes, parts of this have been done before. Sure, there's open-source avionics stacks that can do this thing no problemo. But a controlled return of the first stage of a liquid fuel rocket has never been done before, and this kind of work has most certainly never been done for the relatively tiny amount of money that SpaceX has been spending. *That* is the thing that's getting tongues wagging.

Comment: Re:TSA-like Money for Fear (Score 1) 271

- Cars don't have the long wiring needed to effectively 'pick up' EMP.
- Cars have a lot of 'passive' components that can help clamp EMP to a survivable level, most notably the battery which can deal with all sorts of spikes and has fairly heavy gauge wiring to the engine computer (for fuel injection)
- Cars are also quite well shielded (they're mostly a metallic faraday cage)
- Cars deal with lots of EMP as an everyday occurrence (10,000 ignition pulses at 80+kV in the engine bay every minute)

I won't say it's not an issue, but it's not a big an issue as you believe.

Comment: Re:How long before the FAA stops this? (Score 2) 49

by ColaMan (#46803229) Attached to: Drones On Demand

That's a little odd. CASA here in Australia has authoritah over most aerial devices and imposes a licensing arrangement (for those using them in a commercial manner) and a restriction that they have to maintain at least 30 metres from people.

Someone in a triathlon got whacked in the head just recently with a drone - the person flying it will be in a world of hurt once CASA finishes discussions with them.

Note that if it had been some kid fooling about in the park CASA would not have been interested, but once it becomes 'for profit', they start to take notice. Which is probably a reasonable distinction to take - 'for profit' types will generally be using more of them, more often, and licensing requirements can also mandate that they have adequate insurance and minimum safety requirements.

Comment: Re:Nuclear is obvious, an energy surplus is desire (Score 1) 433

by ColaMan (#46745045) Attached to: UN: Renewables, Nuclear Must Triple To Save Climate

So the entire worlds output of nuclear power is .000000372 ExaWatt Hours.

No, that's just Exawatts. You need to multiply it by the runtime per year, which you can comfortably call 8500 hours, allowing for downtime. So that makes it 3.16 ExaWatt-hours, which is just about a third of oil's output, but you can still have oil for mobile transport for quite a while and flip all the power plants to nuclear, that would certainly help,.

Oh, and perhaps you should consider smoking less crack. Or posting to Slashdot whilst under the effects of said crack. Or both.

Comment: Re:Deepwater Horizon non sequitur (Score 5, Interesting) 290

Ash = ash.
Coal ash is different from volcanic ash.

I used to do ash analysis on coal samples - coal ash is pushing 95% silica and alumina. The rest of the elemental analysis are trace elements, which can be made to sound super-scary when you scale up the quantities to thousands of tons. OMG! There's 100,000 pounds of this KILLER element released! Yes, but it's spread out evenly though 10 million tons of slurry over 100 square miles. You could probably strip-mine the top 5 feet of the same area in a city and find higher concentrations.

The biggest problem is not all the toxic waste, it's all the bloody inert sludge that's everywhere.

Comment: Re:"Back to the launch site"? (Score 2) 73

by ColaMan (#46331909) Attached to: SpaceX Testing Landing Legs On Next Falcon9 Rocket

It seems that the quantity of fuel required to fly an nearly empty 1st stage is negligable. That is, the amount that they normally leave behind as reserve in case of issues getting to orbit is enough for the 1st stage to land with - you basically just fall/parachute as far as you dare and then fire the engines at the last second to steady/cushion the landing.

Two can Live as Cheaply as One for Half as Long. -- Howard Kandel