# LED traffic signals...rescued one!



## Zelandeth (Jun 9, 2005)

Well, noticed on the way to college this morning that one of the LED traffic lights they put up near here a couple of months back had been damaged. It was working just fine, but the lens was broken.

On the way home, it was fixed...but..wait...there's Siemens van parked there *slams on the brakes and dives out of car* Five minutes later, after a breif chat with the extremely polite and friendly technicians, I drove off - with the module they'd just replaced in the car with me /ubbthreads/images/graemlins/smile.gif

So...I now have a green LED traffic light module! Next question: What on earth do I do with it?!? No idea, but that's not the point...it's not something everyone has!

One thing's for sure...these things look a LOT bigger when in your already cluttered room than they do up poles on the road!












Unfortunately, I haven't been able to find any details on it online - thus am at a loss as to how to power it. I know it runs on 230VAC, as it's printed on the board. However, the maker's name isn't even on it (though the fact it was a Siemens van is a bit of a clue!), and thier website isn't exactly forthcoming with datasheets. I've linked to a high res scan of the PCB (~850K), so if anyone can make any sense of the numbers on there, please enlighten me! That green thing at the top left appears to be the power connector, and I think I've found where power goes in...but where it goes from there I have no idea, and I haven't found the neutral yet.

Certainly a far cry from the last LED traffic signal I saw, which was just a bunch of LEDs and a few power resistors on a board! This thing's got a proper regulated power supply and everything. There's actually a black heatsink running right down the left of the image which has a couple of high power resistors and transistors on it. All in all, this strikes me as being a seriously well designed and high quality bit of kit. The anode (I think) of each LED is soldered to a very large copper pad on the PCB for heatsinking - something I've not actually seen other than on custom built things before!






How on earth the lens broke I have no idea! That thing is 8mm thick and made of severely tough stuff. I reckon someone either attacked it with a hammer, or threw a really heavy rock at it with a vengance. Total functional damage: One LED broken, out of 250 odd. A lot of them were squashed, and were easily straightened up but only one was actually split.






So, anyone got any ideas how to go about finding a pinout disgram for this beast? Will be really interesting to see how much light 250 or so modern green LED's can put out...

I am fully aware that portions of that PCB will be at mains potential when the circuit's in operation, just before anyone thinks I'm about to go electrocute myself, I'll be careful.

Will be being careful anyway, as I really don't want to cook such a hard to find bit of kit. Would be nice to replace the broken lens, but that would probably (even if I could get one) cost more than I can afford. Will probably just cut some plastic to size and put it in there.

Large PCB scan (Afraid there's some distortion on the right of the image - was too big to fit in the scanner, so I had to paste two images together. Don't think it's too bad though).


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## PhotonWrangler (Jun 9, 2005)

Huh... so they're PWM'd at 16mhz. Anyway, I'm guessing that the power goes in where the red MOVs are. Those are usually in parallel across the AC Power rails.


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## Zelandeth (Jun 9, 2005)

That much I'd guessed. Which helps me actually locate the neutral line - as that's what they'd be connected directly to...I know what I mean. Tried tracing the positive from the fuse, but it disappears inside the board (this is an at least three layer PCB), and I can't quite follow it. The fact that the entire thing seems to have been painted with a dark coloured laquer makes it even harder - this thing was *designed* not to be reverse engineered I reckon!


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## PhotonWrangler (Jun 9, 2005)

Yuk... I hate those kinds of PCBs. I can understand why it's difficult to trace out what's going on.


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## greenLED (Jun 9, 2005)

Cool! I picked up a pedestrian sign at a yard sale a while ago (the red hand). It's wicked bright, and it can be screwed onto a regular lightbulb fixture.


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## Zelandeth (Jun 9, 2005)

*scratches his head and puts down the PCB again*

Okay, I think I have learned something now. I'm gonna need a datasheet! Unless I get lucky and find someone here who's actually worked with this exact unit before anyway!

I did find something possibly useful: Peeled off the serial number sticker to see if it was hiding anything, and revealed "KALEX3 K688" To me, that sounds like a model number...


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## Zelandeth (Jun 9, 2005)

Gotcha! Found it. It's part of the "Helios" range.

Just need to find a pinout now. Definitely on the right track.

That name I found earlier is a company specialising in multilayer PCB creation apparently.

EDIT: Registered on Siemens Traffic site, and am now downloading the manual for it! This should hopefully tell me what I need to know.

Have to confess, probably took longer than it had to...that place is interesting!


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## BB (Jun 11, 2005)

Zelandeth,

What was the answer? Functionally, is just 230 VAC and return or are there special functions inside? Timers? Dimming? Communications back to the light controller for health checks?

-Bill


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## Lynx_Arc (Jun 12, 2005)

now you just need to screw it on a maglight with a transformer and ballast circuit with a bunch of batteries and have an uber green spotlight.


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## IsaacHayes (Jun 12, 2005)

did you see the "spare" led on the far right corner? If that doesn't light up then maybe you could swap that for the broken one? It says H/B I guess high bright?


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## Zelandeth (Jun 12, 2005)

The spare LED's the "heartbeat" indicator, basically blinks once every few seconds if everything's right.

The manual doesn't even mention supply voltages, thanks to the fact that the unit came supplied with a small switchmode supply unit which should be mounted in the aspect with the LED board. I'm guessing that the main drive for the light IS 230Vac - but the secondary functions require lower voltages, probably for the lamp monitoring, as the Helios range is one of the cleverest signal systems I've seen.

If I could find out which connections were the 230V ones, I'd give it a shot - but not made any progress there yet, nor do I have a clue where I'd find a power supply failing that.


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