Street light photocell : curiosity teardown
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- เผยแพร่เมื่อ 15 มิ.ย. 2022
- This week I'm exploring a photocell that is used to control street lighting.
It's somewhat different from the one Big Clive looked at a couple of years ago ( • Inside a UK compliant ... ), but it does the same job.
Tearing this down put my solder sucker to the test - and it did well, even with the huge pads and big pins. pileofstuff.ca/r/5rclq if you're interested
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This isn't the only way to do it.
It's probably not the best way to do it.
But it's how I do it. - วิทยาศาสตร์และเทคโนโลยี
In mid 90s, I used to make a device like that but with 555 and a triac. I sold them to shop owners that din´t want to bother to switch on or off theirs street lights at night or did not wanted to use time relays. It sold well few months until some shop took the idea and made the same circuit in a professional case (mine was made in transparent plexiglas case)
9:10 R11 is orange white brown. Gold band means 5% tolerance.
Hi - I am based in Australia, in the early 80's i was involved with the major local electrical manufacturer of switched and distribution boards etc.
We had a version sold to local sydney authorities calls the VSSW - Vertical sun set switch.
It was primarily a small solar panel, that could generate up to 5 or 6v dc - this was when the son was shining, there was some storage capacitors and a small battery pack used to store say 30-45 mins power to cover periods of heavy clouds
Anyway one there was no power produced in the photo cell and no battery power for a time delay, there was nil voltage, this then triggered the street lights to activate
Prior to that there was a 24hour timer on a control light ( possibly the control or master was chained and controlled a few city blocks ) - i cannot really recall, but i think they had a cover and a slotted switch that was set to 5pm 6pm 7pm 8pm - this is to allow for different sunset times during the year - a service technician would turn up every 3 or 4 months and change the time on setting
As a kid we would play in the street then at the right time, all the street lights would light up within 5 -10 seconds in the street, a friend who lived 2 blocks down on major intersection noticed that my street would light up and about 30 mins later his street all the light would turn on
Regards
George
Its interesting to learn how similar problems are solved with different approaches in other countries.
Thanks.
"That's huge... OK..."
If I had a dime for every time I've heard that...
I'd still be poor.
Good job! Feedback resistors for the op-amps provides histerezis, the second stage adds some filtering with a large time constant on the positive side and short on the negative. Also snubber diode should be backwards :)
Good catch
I was going to say that but you beat me to it. When the input goes above the trip point the output goes low shunting the lower resistor with the feedback resistor so lowering the trip point. And again as the input drops below the new trip point the output goes high shunting the top resistor with the feedback resistor so increasing the trip point voltage. A simple way of providing hardware hysteresis
The yellow part is the 5G death ray emitter.
Or a 480 Volt Photocell.
@@69BTony Woosh
@@SinKillerJ K, missed it, most photocells I have taken apart do not have the G5, they have the much more clandestine G7 disguised as a resistor.
Interesting things that fall from the sky in Canada! ⚡️🦅
pcb just made me remember something from my childhood years when circuit boards had transistors not marked q1 q2 etc but tr1 tr2, i wonder when q came into vogue
It seems to have happened while the industry standardised on IEC symbols during the late 80s/early 90s. At least from what I've seen in UK electronics magazines. I suspect its to avoid confusion between transistors/transformers etc.
@@IanSlothieRolfe yeah I think 80s on paper and then early 90s products and it happened so slowly and quietly I never realised until today that you'd never really see TR anymore
Not a beer drinker… but that looks good!
if you are from the Winnipeg area and are seeing grey / clear ones they are NOT photocells at all and are only shorting caps and the lights are controlled remotely and that is why the whole street turns on at once
Good to see a quality north American component.
That's the 2nd biggest MOV I've ever seen - lol -. Joke for the oldies, ie, 60's
Curiosity killed the cat. 😂. Glad you did it. I always wanted to!
its funny you mention big clive, you sound like him, lol, nice video by the way.
Good find. Thanks Mr. Pile :)
almost looks like a paint can lid with a window in it
My thoughts exactly!
There should also be a delay function in there somewhere, to prevent false switching in case, let's say for example, a big fat pigeon decides to land momentarily on top of the light, or, in the event of a dark cloud which might obscure the daylight for a short while.
Without a delay, that light would be at risk of erroneous multiple 'ON' cycles during the day, and with it, increased wear and tear to the lamp itself.
Some are a slight delay, some are instant, with the delay being the gradual or partial covering of the eye. So most twist lock photocells will close if you cover with a photocell cover.
Very excellent video!
Relay is incorrectly shown, the relay itself is powered from the power supply with the open collector comparator pulling it to ground. The input has a fast charge, slow discharge, so that it takes around a minute for the light to turn off when the sun rises, but only a few seconds of darkness to turn on. Done so test is easy, cover photocall with a black plastic bag or box, and wait 5 seconds for the relay to energise the light. Also does mean the light comes on for a minute at power on, so allowing a test from the ground, using the fused disconnect in the pole.
By me the photocontrols are a little more complex, though the simple one there is very common, but there are a lot of more complex ones, which use Royce Thompson made units, which also self adjust to light level, so that they will work even in areas where the lamp is shaded by a tree or wall part of the day, adjusting after 24 hours to get the complete cycle, so they will go on at dusk correctly. Complex, with all the control being in a transparent DIP package, so you can see the electronics, and the large photodiode inside.
I think someone needs to make an app (program, I dislike when they rename things) for dumb phones that will display the colour it is pointing at.
There are many already....
They exist ,but I haven't had a lot of luck with them working consistently well
The manufacture is Fisher Pierce Sun Tech
Great video man
The ones we used to use on some of out wall packs had a much simpler circuit. They were driving Soduim or metal halade lights.
Interesting. Quite a bit of circuitry for a simple light level activated switch though!
Drew your snubber diode upside down
Well spotted.
Hi, form your schematic 9:58 the diode across the relay is drawn the wrong way around, all voltage will go to the negative rail and blow the diode or the output of the comparator ic.
Are you a hole flow or electron flow guy?
I don't know if anyone has mentioned one of its functions if it breaks down the light will stay on during the day. This way maintenance people know which light needs a new control.
This is usually the case, but not always, I would say around 75 to 80% of the time. The resting photocell is closed, and you can feel the photocell close when you cover it.
I have a 50w led security light that came off of a utility pole. It has a built in photocell. When connected to the service wire it comes on for a few seconds letting you know it made a connection and when covering the photocell it will not come on. I want to remove the photocell completely from the circuit and run it to a switch instead. How would I go about doing so?
I've had to replace one of my customers dusk to dawn outside floods twice now due to photocell failure. And am truly wondering what causes them to fail. The original lasted years. But I have had to replace two now that only function for about a year or less. Still curious what is going on. So odd.
I understand enough to be dangerous..lol. But trying to get better.
That was very interesting, thank you.
BTW, R11 is 390K (Orange/White/Green).
Sorry, it's a 3.9 megaohm (3M9R).
@@Stuartrusty My bad. Sorry. :)
@@frankowalker4662 Not to worry.
Did you "find" it next to the street lamp before or after you kicked it?
;-)
If I find myself in North America I will be able to find north !...cheers.
Nope, we do it wrong every time
I'm color blind too. Reading resistors is the most frustrating part of this field for me. But what can you do haha. I love SMD for that aspect. Standard resistor Red
Green stripes, can't tell the difference, and blue/violet stripes, I'm hopeless. Don't get me started on 1% resistor body color haha. Though some brands are better.
Someone should invent an app that tells you what colour things are.
@@SidneyCritic Some people already have. And with cameras on every smartphone no wonder, really.
i was halfway thru my first year of electronics and they kicked me out the school when they found out i was colorblind. it was a technical college. always bummed me out. im curious how many lumens is required to make that light turn on or off.
You have different sensitivities for different manufacturers, and different models. You also have some that turn off instantly and some that are delayed. Your 480Volt are usually yellow and let in more light and are therefore more sensitive.
Manufactured in March 2019 using only through hole components?
The same design has probably been used for decades.
That's my guess - an old design that simply and cheaply "just works"
What do you think would happen on this if say you gave it 240v instead of 480?
It would work as advertised. This photocell is ranged from 105 to 305 volts. When he mentioned 480 volts he was talking about the component (looked like a capacitor to me) that acts as a surge protector. Usually if you gave a 480V photocell a lower voltage it would remain on and the light just wouldn't work because it didn't have the required voltage. With the new LED lights everything changes. Older high pressure sodium and mercury vapor needed a specific voltage120, 208, 240, 277 or 480. Led Fixtures are a range, 120-277V or 208-480 or just 480.
Not quite BC but an excellent video nevertheless! Well done m8 :)
Glad you liked it
I cannot read drawn circuit diagrams yet.
Anybody know why the MOV is so gigantic?
Viagra
I would assume for heavy duty surge protection, possibly not sufficient to protect the single light fixture from a direct lightning strike, but enough not to take out all the other lights in the circuit. Just a semi-educated guess.
I have pulled apart many and that component is unusual, but mine are all Torks.
I'm surprised there isn't a variable potentiometer somewhere in the circuit for controlling the switching level, like there is in commercial light sensitive lamps.
so there must be an use case where this is not used, why else have it as a separate module,
or is it more about easily replacing the thing when it is broken ...
saw a video from a London electrician doing highway light replacement, no such thing on top. (Nagy)
The London highway lights probably use time clocks and the dusk to dawn sensors are used throughout the uk on street lighting, UK Electrician
These sensor modules do fail from time to time, and being a 'twist/lock' fitting greatly simplifies replacement. It also provides an immediate line of defence against electric shock in the event of power being accidentally applied whilst being worked on - How? By simply unplugging the sensor, the light is rendered safe.
There are also different sensitivities of these modules to suit varying applications.
Here inSweden I've never spotted anything like this on our municipal streetlights - they're more centrally controlled with [sections of] roads going on/off at a time.
You have some lights that are individually controlled (like you see here) and some that control multiple lights on circuits with a single photocell and an electrical contactor. Some use a motor driven timer like a clock that hits a on and an off switch at times on a dial, and some digital time clocks that you can program with times and days of the week to include holidays and dayliight savings time calculations.
Hmmm, facing north. Lol not west (sunset) haha
Yeah, and depending on the fixture is kinda silly.
snubber diode on drawing is the wrong way around :)
Any gold or silver?
None that I could see.
9%!!!!!!!?! Yikes.
(Can't help myself...)
That's the second highest ABV percentage beer I've ever seen!
(Showing myself out now)
It's green plastic not grey.
It gets repetitive when I mention my colourblindness in every video.
Huge lollipop.. lol (no use for something that range, I think but could be wrong.
Knock off AvE much?