OT - Streetlight

What makes you think there's programming involved?

I doubt it.

I doubt there's any software involved at all.

Let us know what happens.

Probably a component failure of some sort?

What makes you assume there's any programming involved here, in the first place? Why would a street lamp have a CPU, where some analog circuitry driving a relay would do?

Possible: yes. But also rather less than likely.

Wherever I've actually checked so far, street lights went on by the clock, not by the sun. I.e. the were controlled by a central switch somewhere. Now imagine somebody won the bid for installing those lamps by saving the money for a bistable relay with bidirectional active switching (possibly needing one more control wire from the central switch box), and just used a pulsed toggle relay instead.

Maybe a variable intialized at power-up and stupidly never refreshed.

Was there an electrical storm a month ago?

Eg. something like:

int light_off = 0, threshold = 0x80, light_level;

while(1) { read_adc0(&light_level); if (light_level > threshold) output = light_off; else output = ~light_off; clear_watchdog(); // which does absolutely no good in this case }

Best regards, Spehro Pefhany

I did once see a port pin failure in a uC, that flipped the pin polarity. I did not believe the user, so he brought it round to prove it, and he was right : working, not stuck, and flipped.... All I could think of, was some punch-thu of an inverter ?

Street lights are rarely controlled in 'ones' - do others nearby do the same ?

It *is* possible to get phase reversal from a component failure, but MUCH more usually it would stick on or off.

Best regards, Spehro Pefhany

Isn't that pretty obvious? That it's broken.

Imagine that.

--=20 Fredrik =D6stman

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Most of the city streetlights I have seen in the US use a photo-sensor to switch the light on and off. If you look at the lamp from the side, there is usually a small cylinder, about 3" in diameter and a 2" tall on the top side of the lamp. The last one I saw up close used an ancient cadmium sulphide phot-resistive sensor. It should be readily visible with naked eyes and easily studied with a pair of binoculars.

Commercial or parking lot type lights are probably centrally switched instead, but that is a guess.

As for why yours has lost it's little mind, I would guess a component failure.

Bob

1. Write down the pole identifier number.
2. Call the electric utility and tell them their streetlight has a problem.
3. Sit back and wait for electric utility to dispatch a repairman.

1. Go out and chat with the repair folks and find out what was wrong. A cold soft drink or bottled water might be appreciated.

Best regards, Spehro Pefhany

It's fallen into bad company, like my son who stays up all night and sleeps all day. The solution is to get an older streetlight to have a serious talk with it.

Paul Burke

Not necessarily, it could be a computing science student, or even a computing science graduate! Look for discarded 'energy' drink cans nearby...

The street lights where I grew up in the UK were controlled by a light sensor in a substation. I knew because us mischievious young scamps used to put a can over it and giggle ourselves silly when the lights came on. It never occurred to us to shine a torch on it at night to turn them off. But then it never occurred to us how close we often came to dying horribly sparky smokey deaths in the sub station :-o

Perhaps if they were clock controlled as you say but if it was a photosensor then a regular SPST relay would probably be used. I'm sure they must have some kind of failure mode which would reverse the polarity. In my experience whole streets and block of streetlights come on together rather than individuals though.

These photo detectors have a three prong twist-lock plug, wired to a NEMA standard (don't remember which one).

Many years ago, I was a field engineer on a large copper smelter project. We had hundreds of timers, all over the facility controlling the outdoor lighting. Everytime we lost power, all the timers would have to be reset. It would take maintenance several days to get around to resetting them, and we would lose power every couple of days. In other words, the lights were never on at the right time.

Maybe you have a timer that's off by half a day.

-- Hershel

It is an engineering problem all right, not enough time not enough information and not enough resources.

We have the resources of the internet and the local utility company - solved Time : we have all day essentially solved Information: The reverse engineering and fault diagnosis needs help. It seems to me we have missing information

Two of the posts are developing a work flow to get the street light fixed follow..

:)

w..

Spehro Pefhany wrote:

We'd better have a daily meeting to check progress. That'll fix it

Not necessarily. Like your son and myself, the streetlight may have that cycle programmed into its DNA. For us, working "normal" hours is the abnormal thing to do. That poor streetlight was living a charade until it decided it could not take it any more...

Well, last night I took my big hulking hand spotlight and shined it on the sensor for a good 5 minutes and the light didn't come on. I didn't want to press my luck as I looked kind of silly, shining a spotlight on a dead streetlight and the local cops wouldn't grasp the significance of my experiment.

So, to everyone who suggested a timer/remote control, no, it has a sensor.

To everyone who suggested a hardware failure, I am

This conclusion seems at odds with your experimental data.

It's not clear. I've heard that it may take as long as 10 minutes of darkness to get a normal lamp to come on.