>> The City of Los Angeles, California recently announced a plan to >>> monitor and control all of its streetlights via a cellular >>> network, allowing city workers to control the lights remotely >>> from a Web browser, CNNMoney reports.
>>> The system will identify each streetlight's location via GPS, and >>> will allow workers to turn lights on or off and to dim them or >>> brighten them as needed.
> I guess the GPS is needed to keep track of all those fugitive
>> streetlights as they pull up roots and try escaping...
> I was also wondering about that, too -- why can't the streetlights
> identify themselves, and then they look up the location in a
> database?
"Identify themselves" how? Every streetlight has to have some sort of identifying name in order to identify itself. What kind of naming convention would you suggest?
I suspect what they really mean is that workers can be driving
> around in a van. When they see a streetlight they want to adjust, it
> will use GPS to determine the van's location, so it knows which
> streetlight he's near. Then he uses the laptop in the van to send > commands.
The purpose isn't to identify a streetlight so a tech can "adjust" it; it's to make instantaneous adjustments throughout the day. As Bill's original post notes it's to "allow workers to turn lights on or off and to dim them or brighten them as needed."
See the original CNN article here:
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Neal McLain
***** Moderator's Note *****
If I had to guess, I'd say that you're both right: a GPS transponder and logic would allow any streetlight within the bounds of a specified area to respond to an "all on" command for that area.
And, it would also simplify and speed up maintenance: work crews are prone to manage records badly, so having a stock of "one size fits all" lights in a truck, which can be put in place and /automatically/ tracked, would speed up road crew work and assure more accurate recordkeeping.
On Wednesday, April 22, 2015 at 9:13:32 AM UTC-5, HAncock4 wrote: > On Friday, April 17, 2015 at 10:27:47 PM UTC-4, Bill Horne wrote: > >> The system will identify each streetlight's location via GPS, and >> will allow workers to turn lights on or off and to dim them or >> brighten them as needed. > > I'm confused by this. Why is this even necessary? > > Today, streetlights are controlled by a photocell, automatically. > When it gets dark, the streetlight goes on, when it becomes light, > the streetlight goes off. If it becoms dark early, say due to a > bad storm and cloud cover, the lights will go on. Why would it > even be necessary to manually turn them on and off?
Because:
Photocells are not reliable. If it gets covered with bird poop or fails for other reasons the light burns continuously.
There's no way to monitor the operation of individual lights from a central location. If a light burns out or if it burns continuously for reasons cited above, maintenance crews don't know about it until somebody reports it.
There are other reasons cited in the original CNN article here:
I'm not so sure that a command to a rectangular area would be the right thing to do in even most cases. Let's suppose that they need to turn the lights on full blast over a 5-mile stretch of I-20 in the evening because (a) they have to land a CareFlite helicopter there to pick up an accident victim, and want everyone to see backed-up traffic, (b) the highway is closed to demolish and/or install a bridge over it, and they want people to see the signs directing them to exits, or (c) this part of the highway is flooded. I think all of these have happened several times on parts of I-20 in the Dallas/Fort Worth area in the last 10 years. It's also problematic that a rectangular area with one most-significant-bit flipped could shut off half of the city, or country. You shouldn't have to update all the lamps should the route of a small section of I-20 change to know the new route of I-20. Only a few of those lamps will move.
Highways tend to curve around a lot, and sometimes the difference between a light on a highway and a light on an access road are distinguishable only by altitude (My TomTom GPS makes similar mistakes regarding traffic cameras at intersections of access roads and warns me about them on the highway itself). Also, some lights on the same pole (and very close together, perhaps too close to distinguish with GPS) are aimed in different directions and shine on different roads.
How easy is it to do a "cellular broadcast" to a bunch of lamps in an area, without having to make individual calls to each lamp, and without including any non-lamps? Can this be made to cost less than one cellular minute per lamp? How do you prevent telemarketers (or terrorists) from making (possibly collect) calls to the lamps and changing their state?
You can solve some of this by putting smarts in the lamp database, not the lamps themselves. For example, you define an area called "I-20" subdivided by mile markers which resolves to dozens or hundreds of small rectangles, another one for the convention center which often needs lights on when special events get out.
I presume that there are multiple laptops for workers to use, and that under normal circumstances they are returned to the office to get re-sync'd overnight, or they get live updates for the entire city.
Moving lamps might set off an alarm for suspected lamp theft or the pole getting hit by traffic (or blown over by a tornado) so the lamp is lying in the middle of the road.
I still think individual identification of each lamp, by something other than GPS location, is needed. You need to be able to separately control lamps which GPS thinks are at the same location.
Where did "rectangular area" come from? There's nothing in the original CNN article or in any previous post in this thread about "rectangular area".
If they can control each streetlight individually they can define any geometric shape desired to control two or more lights. A linear grouping would be more likely than any two-dimensional shape, but if a rectangular shape is desired it can be defined in software.
If they can control each streetlight individually they can distinguish between two city-owned lights on the same pole. In my experience if there are two or three lights on the same pole only one (at most, two) is owned by the city anyway. Private lights aren't the city's responsibility.
Are you assuming that each light has a separate NANP telephone number? It seems to me that IP address would be a lot easier to implement and faster to use.
Of course the idea of assigning an entire area code to streetlights has a certain perverse fascination...
Hey -- I love that idea. Forward your favorite telemarketer to a streetlight!
Sure. As I noted above, if they can control each streetlight individually they can define any geometric shape desired to control two or more lights.
Or each worker just logs into the central database.
Sure. Assuming that the light's transponder still works after crash-landing in the middle of the road.
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