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Comment: Software TDMA for WiFi (Score 3, Interesting) 137 137

Many years ago when WiFi first came out and internet was still really slow I was active in a community based wireless FreeNet. We had set up multiple 10+ km links between our houses and had a full dynamically routed system spanning most of a city.

Problem was, WiFi is renowned for the "hidden node" problem, where clients cant hear each other and fail to successfully perform collision avoidance. Packetloss goes through the roof and throughput suffers terribly.

So, I wrote a perl script that interacted with IPtables QUEUE feature to keep the wireless packets a buffer, and they would only be released then that client received a token from a master server. It was a massive hack, but worked a treat and gave huge improvements to our throughput and stability.

Years later companies like Mitronik and Ubiquity introduced similar functionality in their wireless station firmware, but we were well ahead of the curve.

Comment: Mostly custom brackets (Score 1) 266 266

I have a solidoodle and mostly print in ABS. 90% of what I print would be custom brackets, but occasionally I make something more significant.

- Replacement car ash tray with 4 port USB charger
- Rotors and bearing mounts for magnetic clutch for my home brewing HERMS system.
- Keg feet and valve brackets for home brewing system
- Open frame power supply terminal cover
- Custom junction box cover
- Tablet stands.
- Custom Odroid mounting brackets
- Bicycle GPS mounting bracket
- Various RPi cases

Next project is a custom diffuser for an air duct vent because I cant buy anything even remotely similar from the hardware shop.

Comment: Re:About time this farce is over (Score 0) 153 153

One of the "trolls" here.

Early on, Swedish prosecutors said categorically they couldn't interview him out of the country either in person or over the phone. Now that it's the 11th hour it seems they can. We all knew they could, they had done it in the past, they were just being difficult.

Personally I wouldn't blame Assange if he tried to drag this final request out. They made him wait 4+ years and put the prospect of statute of limitations within his grasp.

P.S. - interesting how he was trying to "evade justice" when he was co-operative with the first two investigations into the alleged crime, which investigator #2 dismissed as having no case. The third investigation began months later, after he'd been given explicit permission to leave the country.

Comment: Re:You'rte all sensationalist idiots (Score 1) 666 666

Your argument is moot because they actually sell remedies with those ridiculous dilutions. This is the whole point of regulation

See here: http://www.weleda.co.uk/homeop...

These are 30C tablets, which is a commonly advocated dilution. That means it is diluted by 10^-60, according to wikipedia on average this would require giving two billion doses per second to six billion people for 4 billion years to deliver a single molecule of the original material to any patient.

Comment: Re:Scientific worldview undermining own credibilit (Score 1) 666 666

OK, I'll bite.

You didn't read the article did you? Even if homeopathy isn't complete and utter hogwash quackery, the article addresses your claim that it requires a holistic approach.

How can you justify homeopathic products sitting on pharmacy shelves being sold for ridiculously high prices, when in order for them to be effective they must be tailored specifically by a holistic homeopathic therapist? You're shooting yourself in the foot on this one.

Anyway, you're still wrong and homeopathy is complete and utter hogwash quackery, with or without Heisenberg uncertainty there is no valid scientific principle by which it can work. People who promote it are at best deluded, and at worst frauds.

Comment: Re:My vote would be for Beaglebone (Score 2) 32 32

I have both and they each have their own pros and cons.

The Odroic C1 is far more powerful and has gigabit ethernet. This is very usefull and I have two at home running as small file server and a Zoneminder security camera server. Unfortunately, it's not built as well and is not as reliable:
1) It doesn't seem as well sheilded and is a bit sensitive to touch. The reset pin is especially bad, connecting a wire to it (even floating / ungrounded) or touching it with your finger is enough to reset it.
2) Some of my units have a problem booting when standalone, but when I connect a serial monitor they boot fine every time. I'm thinking it's a grounding issue somewhere.
3) It's got incompatibilities with various MicroSD cards, mine works most of the time but from time to time there are I/O errors in the dmesg logs. It makes me worry if i'm corrupting my filesystem.

The RPi2 on the other hand is a bit slower and only has 100MBit ethernet, but is far more reliable. It's much better suited as an embedded controller.

Comment: Interesting experiment but deeply flawed (Score 5, Informative) 59 59

If you RTFA, they didn't just use a regular WiFi access point. They modified the AP so that in addition to one channel carrying data, there were another two radios on non-overlapping channels transmitting noise. Great for powering your thermostat, but horrible for your neighbors.

The spectrum is already crowded with most homes transmitting one channel - imagine if everyone stated transmitting three. The noise floor would go up drastically and WiFi would be rendered near inoperable.

Comment: Re:Yeah, but can you stop the NSA (Score 3, Informative) 66 66

Linux "just running iptables" is perfectly secure.

In general you cant just hack firewall software directly. What you do is find a protocol that is allowed through the firewall and then exploit some vulnerability on that protocol. Examples would be default passwords or SQL injection in a web management interface, buffer overflows in a DNS response, weak encryption in a VPN etc.

Comment: Re:Seriously? (Score 1) 110 110

You can get away with that using smaller "park flier" planes as they are less able to cause damage, but there is risk involved. If you hurt someone you will be personally liable and wont be insured.

By comparison any official club will register with international model aircraft organisations. They train their members in the rules of safe flying, and provide insurance if something goes wrong. A few years ago my local club was $180 per year, not cheap but not too bad considering they have to maintain grounds as well.

Comment: Re:Does This Make Sense? (Score 1) 318 318

Crappy single phase AC motors have sucky low end torque because they dont have a second phase to produce and offset magnetic feild. They have to fake this second phase using capacitors, split coils, shaded poles etc, and those virtual second phases are quite weak.

Three phase AC motors have no such issue. They can produce high torque at low speeds, and can have quite consistent torque over a large range of speeds. This is perfect for a car as it gives you smooth acceleration.

Comment: Re:Haven't quite got my attention yet (Score 1) 318 318

A relatively cheap option for a controller is a 3 phase VFD (variable frequency drive) coupled to a three phase induction motor. Internally the VFD rectifies three phase mains to high voltage DC, so you just string up the batteries in series and it accepts the input power just fine.

Getting the regenerative braking to work is a bit harder though.

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