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Interesting Items...

A first for me: driving back from Cardiff yesterday I saw a van... with the sides and back fitted with (I presume) dot matrix LED panels displaying the desired logos/advertising.

In the daylight, from a distance, it was not obvious these were LED panels, apart from the "decorated area" being oddly straight sided, and being a bit brighter than one might expect (I initially thought it was luminescent paint). Dunno what they do at night, as is it would be rather obvious.

The displayed image was static, it might be illegal to show moving graphics.
 
Like the LED indicators that some newer cars have? Mind I am surprised LED car lights are not illegal anyway as they cannot be seen from side on.
 
Yes they can. :frantic:Mine has repeaters on the door mirrors and the indicator lenses are shaped to direct the light sideways as well as forward.
 
Black Hole said:
The displayed image was static, it might be illegal to show moving graphics.
Click to expand...
Quite possibly. It would be very distracting. You wouldn't want some sort of moving blue image would you? Might give the impression you're an emergency vehicle. That would be illegal.
 
Flashing lights on vehicles are regulated and it would be hard to make a moving image on a screen without at least some pixels turning on and off - technically flashing.

gomezz said:
Like the LED indicators that some newer cars have? Mind I am surprised LED car lights are not illegal anyway as they cannot be seen from side on.
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I'm sure OEM ones comply with the regs, which often aren't as wide as you'd think - e.g. check the requirements for side repeaters.
I suspect some 'upgrade' LED bulbs may not comply. Sometimes they only have front facing LEDs which don't have the same angle of view as a filament bulb.
 
Electronics Weekly 28/02/2018 said:
'Single Atom in an Ion Trap', a photograph taken by Oxford University's David Nadlinger, has won the top prize in a national science photography competition organised by the Engineering and Physical Sciences Research Council (EPSRC).

The image of a single positively-charged strontium atom shows the atom held almost motionless by fields emanating from the metal electrodes surrounding it. The distance between the needle tips is about 2mm. The atom absorbs and re-emits light particles from a blue-violet laser operating in an ultra-high vacuum chamber, travelling fast enough for an ordinary camera to capture it in a long exposure photo.
Click to expand...

Not sure about that last sentence, but here's the photo of the scintillation from a single atom!:

85535A3E-C060-4E26-BDBB-7ED912F585AA.jpeg
 
Black Hole said:
Not sure about that last sentence, but here's the photo of the scintillation from a single atom!:
Click to expand...
If the researcher and EPSRC say so. I don't find the photo very instructive at all. It's like the Emperor's new clothes. I'm being told I see something. I don't!
 
EEPhil said:
If the researcher and EPSRC say so. I don't find the photo very instructive at all. It's like the Emperor's new clothes. I'm being told I see something. I don't!
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It's the "travelling fast enough" bit that got me, I'm content with the rest of the explanation.

What don't you see? The atom? Zoom in on the picture, specifically the area between the flat electrodes top and bottom, and the needle electrodes left and right.

Maybe "scintillating" isn't the correct technical term, perhaps I should have said "fluorescing", but I'm happy to accept that this has been taken with an ordinary camera and does indeed show emanations from one single atom. The only other times I can think of where "pictures" have been shown of single atoms they have been images created from the output data of a scanning tunnelling electron microscope, rather than an actual picture taken with an actual camera (albeit a modern digital camera with a very high quantum efficiency).

However, I suspect this is still not a "naked eye" phenomenon. The fluorescence/scintillation/whatever is, I guess, extremely faint - by definition the strontium atom will only be able to emit one photon at a time and there only be a small chance of getting excited for the next photon (in any short time interval) by being hit by a photon from the laser. I don't know how many photons per second are needed to stimulate the photo-receptors in the human eye.

So the achievement demonstrated by the photo is being able to isolate a single atom in a trap, and then holding it stationary enough that multiple photon emissions are not too "smeared out" in a time-exposure photo.

When somebody can show me a naked-eye single-atom phenomenon, I will be very impressed.
 
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Black Hole said:
What don't you see? The atom? Zoom in on the picture, specifically the area between the flat electrodes top and bottom, and the needle electrodes left and right.
Click to expand...
:rolling:
Bloody hell! I can see a spot! But, if you have to zoom in that close it could be a jpeg artifact or a speck of dust. I still think the Emperor is in the buff!
 
Not sure if this counts as interesting, but it's somewhat amusing.
Three years ago we moved from Cheshire down to Hampshire. At the time we did all the due diligence of telling everyone our new address.
This included my wife telling Specsavers, but all this time later they themselves perhaps need to see a different optician ...

specsavers.JPG

Local store?
 
That's what happens when the admin is left to computers.

I cashed in a £5 eye test offer at Specsavers a few weeks ago - when I booked there were no convenient times available at my usual branch in town, so I switched to a branch at a smaller town only a few miles in the other direction with easy and free parking. However, I was surprised to find they had no access to my records at the other branch: it turns out they are franchises.
 
Black Hole said:
it turns out they are franchises.
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Ah, that would explain it. I never thought of that.
Still, if someone said they've moved 200 miles away from my shop I'd be inclined to just take them off my list instead of wasting money mailing them for years after.
 
It really doesn't cost them very much - I imagine they are paying a one-off fee to the Royal Mail (or some other handler) for all their post. It's probably more expensive to manually review their mailing list and make a decision to remove you. If you ask them to remove you, they have to (and they haven't had the expense of finding out for themselves).
 
"It also allows the Raspberry Pi to be used as a server, for streaming television to other networked devices."

46758789-1741-4725-9C67-7AA001EE1BF3.jpeg
 
Interesting device addition - I'd like the satellite receiver version, as I have a handy aerial feed but not a terrestrial feed.
 
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