If you live in a city with tall buildings, take a look at the night skyline. The buildings probably have flashing lights on them to help aircraft pilots to identify the shapes of buildings and not fly into them.
You might notice that the buildings flash in synchrony, even though they are hundreds of metres apart. What's going on?
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ajft
in reply to Deborah Pickett • • •Deborah Pickett
in reply to ajft • • •ajft
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Deborah Pickett • • •The idea is that all the lights on a given building should flash together. That way, an aviator can visualize the solid space between lights that blink the same way. Blink same? Don't fly. Blink different? That's a gap.
And that's how it worked for a while. A building's owner would wire all the lights together and feed them with a centralized oscillator signal.
Later on, when wire got expensive and buildings got taller, they switched to short-range radio, with one transmitter sending the blink signal, and each light having a receiver in it.
This worked fine, because all oscillators will drift eventually, so every building gets a different blinking pattern.
Then GPS happened.
Deborah Pickett
in reply to Deborah Pickett • • •Now you can buy a beacon like this one, which is standalone and has a GPS receiver in it. Anyone who's cobbled together an NTP server will know that the GPS system can provide microsecond-accurate time as a side-effect.
So these beacons don't care where they are, but they all know exactly when "now" is. And they can synchronize to each other by synchronizing to the GPS signal. It makes maintenance _so_ easy.
Ursidinoj/The Bjornsdottirs
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Ursidinoj/The Bjornsdottirs • • •Ursidinoj/The Bjornsdottirs
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Deborah Pickett • • •Trouble is, these beacons come preset to a particular blink pattern, and when you buy one (ten, fifty) you're probably not going to bother to change the blink pattern in them all. What if you forgot to do one?
So what happens is that your building is synchronized to GPS, and so is your neighbour's building, and so is _their_ neighbour's building. The whole city flashes once every two seconds, like clockwork.
Completely negating the whole point of having one blink-pattern per building, and rendering aviation around tall buildings unsafe again.
It's an accidental own-goal, brought about by the efficiencies of global, perfect, timekeeping.
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Deborah Pickett
in reply to Deborah Pickett • • •🇵🇸 Mari :nb_crossbow:
in reply to Deborah Pickett • • •hi yes hello I was part of an art project that made use of this idea and I think of it every time I see groups of blinky lights ^_^
kickstarter.com/projects/96622…
we ended up building our own lights and controllers and firmware for it, mostly because they would also - about every 10 minutes - display the speed of a seismic wave thru that particular soil geology github.com/ArdentHeavyIndustri…
GitHub - ArdentHeavyIndustries/straightedge-gps-firmware: Firmware for the Trinket Microcontrolers that control the GPS and leds
GitHubDeborah Pickett reshared this.
🇵🇸 Mari :nb_crossbow:
in reply to 🇵🇸 Mari :nb_crossbow: • • •hey I wanted to massively apologize for unintentionally hijacking your educational thread 😅 I had absolutely *not* anticipated the wildly different direction the conversation went
and I also wanted to ask about how y'all had worked it out from first principles! because that sounds like a lovely conversation and represents so much of what I love about fedi
Deborah Pickett
in reply to 🇵🇸 Mari :nb_crossbow: • • •@bouncinglime No apology needed! It was not perceived that way!
The detective work was largely:
• They must be synchronizing to something wide-area.
• Even in parts of the world that don’t do the shortwave radio clock thing.
• They seem to flash for an exact number of seconds.
• If it’s GPS then there must be GPS-enabled beacons for sale online.
• Web search > oh, lookit that.
JodieM
in reply to Deborah Pickett • • •Misinformation-Superhighwayman
in reply to Deborah Pickett • • •Francis 🏴☠️ Gulotta
in reply to Deborah Pickett • • •This is a wonderful dive into something really interesting 👏
Thank you
Irenes (many)
in reply to Deborah Pickett • • •Jorge
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Jorge • • •furicle
in reply to Deborah Pickett • • •Jorge
in reply to Deborah Pickett • • •Jonathan Hendry
in reply to Deborah Pickett • • •@jorgeyanesdiez
If the buildings are that close together it might be safer to have them on the same blink schedule so they appear to be one contiguous structure. Because you probably don’t want anyone trying to fly between them.
Jorge
in reply to Jorge • • •Deborah Pickett
in reply to Jorge • • •Gunnarsson
in reply to Deborah Pickett • • •coldclimate
in reply to Deborah Pickett • • •Philip N Cohen
in reply to Deborah Pickett • • •mid-air collision
Contributors to Wikimedia projects (Wikimedia Foundation, Inc.)crater🐮n
in reply to Deborah Pickett • • •Deborah Pickett
in reply to crater🐮n • • •crater🐮n
in reply to Deborah Pickett • • •Willow :trans_flag: 飛柳
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Willow :trans_flag: 飛柳 • • •CASA Standards For Obstruction Lights (Australia) | Reddotsignal
Reddotsignal (REDDOT Electronics)Alexandra Magin 🏳️🌈
in reply to Deborah Pickett • • •Weasel
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Weasel • • •@weaselx86 Thank goodness buildings are built on a grid 131072 to the degree! 🙃
But seriously, they are already made with customizable blink timing patterns, but the fact that you see entire cities blinking like one giant Christmas tree tells you how much this feature is being used.
Weasel
in reply to Deborah Pickett • • •Right, the lack of use of the customization is why I was looking for a manufacturing default that might accomplish the desired purpose.
Saying "bottom bits" was cavalier of the details; but the GPS has the location, and I'm confident it's possible to develop a location-based algorithm that could distinguish buildings reasonably well without requiring they be build on a grid. It seems like the manufacturers could improve the situation without cooperation from the field.
a software
in reply to Deborah Pickett • • •similarly, back before GPS, radio altimeters, etc, if two flights were accidentally assigned to the same flight level, differences in their barometric altimeters meant they would probably miss each other even if they got quite close.
So after the tech advances, everything is right at the altitude it’s been put at and the danger of collision went up for a while.
That’s fixed now, but only because they built an entire traffic avoidance system to avoid this (TCAS)
Deborah Pickett
in reply to a software • • •John Kaniarz
in reply to Deborah Pickett • • •Since most cars have nav systems now, maybe they could finally sync turn signals.
No more watching your blinker go in and out of phase like an Orbital song.
Philipp Riederer
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Philipp Riederer • • •Arnim Sommer 🇪🇺
in reply to Deborah Pickett • • •I was hoping for something like fireflys syncing!
Deborah Pickett
in reply to Arnim Sommer 🇪🇺 • • •Arnim Sommer 🇪🇺
in reply to Deborah Pickett • • •Resuna
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Resuna • • •Trammell Hudson
in reply to Deborah Pickett • • •Trammell Hudson
in reply to Trammell Hudson • • •and due to Mastodon's missing reply problem, I didn't realize that one of the artists had already mentioned it! spanner.works/@bouncinglime/11…
🇵🇸 Mari :nb_crossbow:
2023-08-24 02:09:56
John Seghers
in reply to Deborah Pickett • • •I've seen this coordinated blink across large wind farms as well.
Problem with windmills is the lights are the top of the tower...not the reach of the blades.
DeterioratedStucco
in reply to Deborah Pickett • • •Interesting. I'd have thought that modern cities are so light-cluttered that there's very little chance of being able to resolve individual buildings anyway.
I've an interest in this (my last serious job related to pilot-training software, mostly relating to airlines) but no specific knowledge.
Caspar C. Mierau
in reply to Deborah Pickett • • •Julien Goodwin
in reply to Deborah Pickett • • •Deborah Pickett
in reply to Julien Goodwin • • •RealGene ☣️
in reply to Deborah Pickett • • •Marine buoys and lighthouses all have locally unique flashing and color patterns so that you can positively identify them to triangulate where you are:
"Fl G 6s" = "Flashing Green every six seconds"
mhoye
in reply to Deborah Pickett • • •Michel
in reply to Deborah Pickett • • •Willem Wits - Knipperflits (Official 8 Hour Video)
YouTubeDeborah Pickett
in reply to Michel • • •eons Luna
in reply to Deborah Pickett • • •Deborah Pickett
Unknown parent • • •Deborah Pickett
Unknown parent • • •Carol (Nichols || Goulding) ꙮ
in reply to Deborah Pickett • • •reshared this
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Deborah Pickett
Unknown parent • • •Leon Bambrick
in reply to Deborah Pickett • • •Deborah Pickett
Unknown parent • • •é.
in reply to Deborah Pickett • • •