I had a strange experience while I was out geocaching this past weekend. I thought I heard a boombox and figured I was close to a picnic area, but when I went around a bend in the trail, I discovered it was just a guy singing opera as he walked along. I didn’t recognize it.
I don’t think he had a bad voice or anything, but it’s not the experience I’m looking (or listening) for when I hit the trails.
BMW tests ‘1,000 times brighter’ laser headlights
The intensity of laser light poses no possible risks to humans, animals or wildlife when used in car lighting, BMW says reassuringly. The automaker says that’s because the laser light is first converted for use in road traffic, a bright, white that “is very pleasant to the eye.”
Maybe your eyes, but we’re not sure about everyone else’s. Did we mention laser headlights are 1,000 brighter than LEDs. Oh yeah. We did.
Yes, you did. Only that’s not what the BMW press release said. What they do say is
[L]aser lighting can produce a near-parallel beam with an intensity a thousand times greater than that of conventional LEDs. In vehicle headlights, these characteristics can be used to implement entirely new functions. Also, the high inherent efficiency of laser lighting means that laser headlights have less than half the energy consumption of LED headlights. Simply put, laser headlights save fuel.
So the observation is that lasers are 1000 times brighter than LEDs, which gets contorted into the claim that the headlights are 1000 times brighter. But they won’t be using as many lasers as LEDs — the goal is to save on energy use. The bottom line here is that laser diodes are more efficient at generating light than LEDs. You would lose that energy savings if for some reason you simply turn the brightness up to eleven.
A single statistic will make this clear: whereas LED lighting generates only around 100 lumens (a photometric unit of light output) per watt, laser lighting generates approximately 170 lumens.
For comparison, in generating white light the best you can do is about 250 lm/W. Presumably you would be using the same technology (phosphor or something else) to generate the white light, so you have to be more efficient at generating the photons.
The way you do this is by making more efficient use of the light. Laser diodes are LEDs with mirrors at both ends of the material, fashioned from cleaving the material — you get reflections whenever you pass from one medium to another with a different index of refraction. You can enhance or suppress this with the appropriate coating; high-power lasers will have a good reflector on one end of the lasing cavity and an anti-reflection coating on the other. Without the mirrors the light from the electrons spontaneously dropping down from one energy band to another can go in all directions. The mirrors allow for stimulated emission, and that will give you gain for photons that can reflect off the mirror and make another pass (or more) through the material. This means you are wasting a much smaller fraction of the photons to spontaneous emission. If you do something to the facets and interrupt the ability to lase (and I’ve seen this), the device reverts to just being an LED. One shortcoming is that laser diodes generally have a shorter lifetime than LEDs — they are static-sensitive and the coatings age — so for this to be viable there has to be the expectation that the lasers will last for several years.
One small leap for running robots
Unlike what we see at the movies, current bipedal robots are a long way from outrunning humans and leaping onto buildings.
In fact, says Wyeth, the fastest running robot does little more than a “quick shuffle”.
“Technically it is running because both feet are in the air, but only very briefly,” says Wyeth.
“Most two-year-olds could pretty effectively outrun these robots.”
Sure, I want ideas for things to do with my own GoPro camera, but this is not one of the things I would do. He comes insanely close to “landing” partway through.
A micro camera is installed onboard an r/c plane F-16. The camera transmit live the video to ground and I wear video goggle to fly the plane in real time like if I was in the cockpit. The camera replace the head of the pilot and the movement of the cam is control by the movement of my head on ground via a head mount gyroscope (head tracker)
What’s it like?
This is what it’s like to be shot at with an AK-47
Trent Kimball, CEO of Texas Armoring Corporation (TAC), was tired of customers asking if his company’s bullet-resistant glass in its armored cars actually resisted bullets. So he did what any reasonable CEO would do: he asked his employee to shoot at him with an AK-47. It’s loud, scary, dangerous, and completely awesome.
Researchers show ATM theft by thermal imaging
The research team from the University of California, San Diego, found that their cameras picked up a PIN entered on a keypad more than 80 percent of the time if used immediately. If used a minute later, it picked up the digits about half the time. After 90 seconds, the chance of extracting the digits dropped to about 20 percent. They tested the frequency using custom software that they wrote to automate their analysis.
Not sure how big of a threat this would be for someone who walks up to a machine. I haven’t had to use an ATM is a while, but in the transactions I’ve done it seems that there is a reasonable (from a security standpoint) delay between PIN entry and finishing your transaction. I expect the threat would be from a camera mounted along with a skimmer.
A series of videos from the Institute of Physics (IoP) that teach elementary radioactivity.
Each video is half as long as the one preceding it
This was made with the “hairball” setting (image rotated to fit better)
