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Comments

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SpaceX Falcon 9 Blasts Off From California

Maddog Batty Re:Reusable first stage? (97 comments)

Elon Musk @elonmusk

Rocket booster relit twice (supersonic retro & landing), but spun up due to aero torque, so fuel centrifuged & we flamed out

Elon Musk @elonmusk

Between this flight & Grasshopper tests, I think we now have all the pieces of the puzzle to bring the rocket back home.

about 10 months ago
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Is Bitcoin Mining a Real-World Environmental Problem?

Maddog Batty Re:Conversion (595 comments)

Yes that does seem to be the case

about a year ago
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Dutch Artist Admits Faking Viral 'Human Bird Wing' Video

Maddog Batty Re: Not Surprising. (125 comments)

The wings were driven by electrical powered motors controlled via Wii remotes. Movement of the guys arms made the wings move the same way. So not human powered at all.

(Ok, ok, CGI electric motors)

more than 2 years ago
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LED's Efficiency Exceeds 100%

Maddog Batty Re:No (502 comments)

No it isn't fiddling with numbers. You are missing the heat pump bit.

The device is taking X amount of energy from the electricity supply and X * 1.3 of energy as thermal and converting this to X * 2.3 as light. i.e. it is 230% efficient when comparing light output to electrical input. Equally, it is 100% efficient when comparing light output to electrical and heat energy input combined.

This does take a little bit of thinking to get your head around but I have a more common example in the shed outside. It contains a heat pump which is 350% efficient. It takes 2kW from the electricity supply and outputs 7kW of heat energy to heat my house. The missing 5kW comes from the pipes in the garden as heat energy. The result being that the garden is slowly being cooled. http://en.wikipedia.org/wiki/Heat_pump

more than 2 years ago
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Raspberry Pi Production Delayed By Factory's Assembly Flub

Maddog Batty Re:Magnetics (132 comments)

I have no idea what this means. How is this possible?

I guess because you didn't study properly at school... ;-)

"Without them you would effectively tie the RX and TX signals together and probably turn the entire network into an aerial for Radio 2 reception."

I disagree with the first part of this. Ethernet works off differential signals and the transformer does a good job of removing the common mode signals (non differential) coming down the wire. Without the magnetics the common mode signals (such as DC, mains interference, Radio 2 transmissions) picked up by a potentially long ethernet lead will turn up at the input to the ethernet phy (receiver) chip. This may or may not be enough to stop it from working depending on the interference received. The lack of correct voltage biasing (also done via the magnetics) will very likely stop it from working though. Even so the RX and TX won't be shorted.

more than 2 years ago
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Growth of Pseudoscience Harming Australian Universities

Maddog Batty Re:Perhaps study these treatments scientifically? (566 comments)

Studies have repeatedly shown that prayer helps in hospital situations. Why? Maybe people just feel comforted or a sense that somebody cares about them and wants them to make it. What's the scientific explanation? I haven't seen a good one. But more people recover and have less complications.

Show me a double blind experiment which shows prayers work? Properly conducted double blind experiments has shown that prayer does not work. The experiments which do show a result, the patient knows that they are being prayed for and/or are doing the praying themselves. Sure it may help these people but this is due to the ritual causing the person to self heal. No super power is involved at all.

If you disagree and think prayer does work in the double blind, go and speak to http://www.randi.org/site/index.php/1m-challenge.html and he will give you $1million when you succeed.

more than 2 years ago
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Growth of Pseudoscience Harming Australian Universities

Maddog Batty Re:Fundamentalists (566 comments)

I wish I had mod points for this and your other posts. Well put.

more than 2 years ago
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Why the Raspberry Pi Won't Ship In Kit Form

Maddog Batty Re:Assumptions (240 comments)

44pin Quad Flat Pack are trivial to remove and replace with the right tools - which basically means a hot air gun with the small nozzle. A couple of weeks ago I removed and replaced two 144 pin quad flat pack devices with 0.6mm pitch legs in about 10 mins. It isn't something I want to do for production boards but it is fine for the development boards I was using.

Screen printing solder using solder masks + ovens are easily within the hobbiest market now. You can get a custom PCB + solder stencil made for £40 (100mm^2) and I use a £50 oven to melt the solder. Gives good results too (though I still do the sub 1mm pitch pins by hand as I get too many shorts otherwise).

I've not attempted BGAs as I could see that the success rate might not be too high.

more than 2 years ago
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Controlled Quantum Levitation Used To Build Wipeout Track

Maddog Batty Re:THIS IS FAKE (162 comments)

Look carefully and the vapour trails go through the walls.

more than 2 years ago
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Customers Gleefully Mock Best Buy's $1,095.99 HDMI

Maddog Batty Re:They may be mocking the price but (369 comments)

To the casual reader, it looks like Timbo is replying to this post:

Yes, how dare you philistines mock the $1,095 HDMI cable? The zeros and ones are so much sharper and clearer than the zeros and ones transmitted over cheap cable.

This is why we quote excessively.

no, we don't

How do you quote?

more than 2 years ago
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MIT's New Camera Can Take 1 Trillion Frames Per Second

Maddog Batty Re:What (197 comments)

A succinct answer and basically correct.

My understanding of this is the clever part is the very short pulsed laser combined with a very short exposure camera. Each laser pulse send lots of photons together in a bunch across the field of view of the camera. Some clever camera synchronisation allows each "frame" taken by the camera to be slightly (pico seconds) later than the previous one. When run as a movie, this appears to show a light pulse as moves across the field of view.

However, it doesn't take a picture of a single photon - it takes pictures of a bunch of photons and neither does it take a movie of the same bunch of photons moving across the field of view - each frame is taken of a different laser pulse.

(for simplicity I've ignored the fact that the camera is a line scan camera rather than full frame camera)

more than 2 years ago
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The Sports Footage You Won't See Today On TV

Maddog Batty Re:why is it football, again? (277 comments)

It isn't called "football" (that is a different game, where the foot is used most of the time to move the ball), it is called "american football". The first word of this should explain everything...

about 2 years ago
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Min7 Micromouse Robot Solves Maze In 3.921 Seconds

Maddog Batty Re:Compared to what? (58 comments)

It is a standard Micromouse maze which has been around since the late 1970s (what do you mean you haven't heard of it?). 16 x 16 grid 180mm square.

about 2 years ago
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Min7 Micromouse Robot Solves Maze In 3.921 Seconds

Maddog Batty Re:all mazes are solvable (58 comments)

Err. No.

Wall following only works if there is only one possible route to the centre without back tracking. With more than one route (as per these mazes), wall following will cause you to go around in circles and will never solve.

about 2 years ago
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Raspberry Pi PCB Layout Revealed

Maddog Batty Re:complex routing ? (112 comments)

I'm with you on this. It looks to me that someone took time and care over it to keep the tracking to a minimum but not anything special. I have a draw full of PCBs which are similar and I don't claim to be particularly good at PCB design.

more than 2 years ago

Submissions

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SpaceX Landing Video Making Progress

Maddog Batty Maddog Batty writes  |  about a month and a half ago

Maddog Batty (112434) writes "The fine people at the Nasa Space Flight Forum are making good progress on restoring the corrupted landing video reported earlier. It worth looking at the original video to see how bad it was and then at the latest restored video. It is now possible to see the legs being deployed, the sea coming closer and a big flame ball as the rocket plume hits the water. An impressive improvement so far and it is still being actively worked on so further refinements are likely."
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SpaceX are looking for help with "Landing" video

Maddog Batty Maddog Batty writes  |  about 3 months ago

Maddog Batty (112434) writes "SpaceX recently made the news by managing to soft land at sea the first stage of rocket used to launch its third supply mission to the International Space Station. Telemetry reported that it was able to hover for eight seconds above the sea before running out of fuel and falling horizontal. Unfortunately, due to stormy weather at the time, their support ship wasn't able to get to the "landing" spot at the time and the first stage wasn't recovered and is likely now on the sea bed.

Video of the landing was produced and transmitted to an aeroplane but unfortunately it is rather corrupted. SpaceX have attempted to improve it but it isn't much better. They are now looking for help to improve it further."
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So You Want to Flap Your Arms and Fly?

Maddog Batty Maddog Batty writes  |  more than 2 years ago

Maddog Batty writes "Take the accelerometers and gyroscopes from an HTC phone and a Wii remote (http://www.humanbirdwings.net/about/haptic-wing-mechanism/) and connect to your battery powered flapping mechanism. Make the wings from your old kite and add ribs to give the correct profile. Attach to back, run down field, flap arms, take off and fly! (http://www.humanbirdwings.net/) Warning there is a bit of swearing at the end of the video (http://youtu.be/GYW5G2kbrKk). Note: this is battery powered flight not human powered but very cool nevertheless."
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The Fallout from a Flickr DMCA Takedown

Maddog Batty Maddog Batty writes  |  more than 2 years ago

Maddog Batty writes "Dave Gorman ( http://en.wikipedia.org/wiki/Dave_Gorman ) a UK comic and Flickr user recently received a DMCA takedown notice for one of his own pictures (copy http://www.flickr.com/photos/dgbalancesrocks/6800943616 ) which had become rather popular — 160,000 views + lots of comments. The takedown was in error (from a porn company) and Flickr allowed him to repost the image. However, the fallout ( http://gormano.blogspot.com/2012/03/if-this-picture-looks-bit-familiar-it.html ) is that all the original comments are now lost and the many links to the original picture are now broken. Sure Flickr needed to remove the image, but surely there should be a way to reinstate it keeping all the original comments and links?"

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