Teardown of an LED Traffic Light Module

Hello, and welcome to Technology Connections2! This is the very first video for this channelwhere we are gonna be taking apart one of these.

This is a 12 inch traffic light module.

Normally these are sitting up high in theair and telling you whether to stop or to go.

Now, these newer styles–I've always beena little bit curious about what the optics are inside, how exactly the LED emitters arearranged and, you know, what's inside of these.

So today I'm gonna take one apart.

Now, this one I featured in my video on TechnologyConnections which is probably how you got here.

If you didn't get here from seeing that youmight want to check out this card, or there will be a link on the end screen.

But in addition to this red one, I also havea yellow one.

You'll notice that their wires are color-coded– Very handy! And what's more, I also have a green one.

Now, this green one is a little bit differentfrom the other two because the green one– its lens is clear.

So I did buy a set of three but this one probablydoes not match with the others.

So I'm gonna take this one apart.

There doesn't appear to be a way to take theseapart without destroying them because they are sealed.

So, uh, let's just take a look.

One thing before I take it apart.

Let me turn it back on.

This is what I've been using to power it forthe video by the way, this is a, uh.



power pack but it has a 110V outlet.

These do run on 120V AC because that's whatwould be commonly used in America during these installations.

Now, one of the things about these particularstoplights is you'll see they have a very, pretty tight focus.

So I'm shining this at you.

And of course the reason why they have thattight focus is because they might as well be pointed in the eyes of drivers so thatway they can see them better.

So they're focused pretty narrowly that wayyou can see them.

So what exactly is on the inside of theseto make that tight beam? That's what I want to find out today.

So, let's take a look! Alright, to make this just a little bit easieron myself, you are on a tripod on top of the table.

Hello! And you're gonna just watch me do stuff.

Because that's fun.

So these traffic lights have a rubber gasketaround them that we're gonna remove.

And as I was saying in my last video, theseare designed to be sealed so if you take a look around the edges, there's really no wayto get into these.

On the back, there was a single screw righthere, but that screw just covered the wire terminal connections.

And really there appears to be no way to getinside this without being destructive.

You can sort of see around the edges herethat you can see the clear plastic of the lens, in fact–I'll bring the red one over.

Maybe you can see on video but that is redplastic you're seeing behind here.

So I think the easiest way to get inside ofthis is to just use a cutting wheel and, uh, cut it open.

I might try just prying it open real quickwith a screwdriver, see if that's productive at all.

And after that I have, uh, a Harbor FreightDremel tool.

That oughta get us in.

So let me grab that screw driver.

(sped up) I think we're gonna make it without the Dremel tool! (sped up) Ahh! We have layers! OK.

So apparently this clear plastic thing–thisis probably the only part that's colored on the red and yellow ones.

So I would imagine that, uh, down below thisis the same.

And then we have this sort of prismatic lens.

This is what gives it the look of the incandescentlight.

And then there's a Fresnel lens beneath it.

That's a lot less interesting than I thoughtit might be! (laughter) So let's take a look.

Right (said with a bad Scottish accent).

I'm just kidding, I'm not Big Clive.

I do not have his expertise here.

But, let's go ahead and turn this back on.

This by the way is how I've been driving these, this is a little power pack with a 110V plug on there.

Really cool.

Let's see how painful this is.

Now, when these are running off of true linevoltage they don't buzz at all, it's just on the inverter that's it's kind of buzzinghere.

But yeah it's just, let's see, four– eightindividual chips, probably eight 1-watt LEDs down here.

Let's blind you.

Oh it's not too bad actually.

So the Fresnel lens, here.



Oh wow! That's really.



So this is basically magnifying them.

I'll show–I'll point you up at the wall soyou can see how it's pointing at the ceiling right now.

And then this distributes that so it's a littleless crazy.

Here's the weather seal.

So this keeps moisture out.

In fact, you can see.



let me turn this backoff.

The interior of this is remarkably clean.

And I'm sure these were in service, I doubtthese are new.

Their exteriors are a little dirty, especiallyin here, but inside it's almost immaculate.

(sped up) Let's go further! (sped up) Oh! OK So this is the board that the actual LEDs are on and I noticed this is aluminum.

Here, so this is its heat sink.

It's a bit surprising there's no thermal compoundbetween the two.

But I suppose in, these aren't–especiallyfor green, they're never–well none of them really, they're never gonna be on for morethan two or three minutes at a time before they're off again, and even if there werea flashing red that would only be a 50% duty cycle.

(sped up) Well that's one way to do it.

(sped up) So that's it! This is all that's inside there, it's justa big plastic shell to direct the light from these eight LED chips, which the board saysLumileds here.

Or maybe it's "Lumi-LEDs" I'm not sure.

But on the back, in addition to a whole bunchof gibberish it says Luxeon so I'm sure these are Luxeon chips.

And then this is basically just a 120V powersupply here 'cause this is an American stoplight so it's on 120V AC.

This is a pretty robust power supply board.

All the components on there–granted, I amno expert but all the components on here seem generously sized, these resistors are quitelarge and the capacitor–what's it's temperature rating? Ehh, I can't see it.

Oh, I don't want to talk to Florida.

(received a phone call while recording) Ooh! It says on here, "GELcore" Maybe Gel-core? Or General Electric Lighting core? I don't know.

I don't know what that would be.

Oh! There's a lot of chips down here.

Integrated circuits.

If Big Clive would like to have a look atone of these and tell me more what this is, feel free! But yeah I mean, this board here is clearlyjust the LEDs themselves.

I would be curious to know if this is simply, like if Lumileds makes these knowingly that they're for a stoplight or if this is justsome sort of general purpose illumination board that they have.

I should see, is there are year on these? Not that I can see.

Well anyway, that's.



I guess that's about it! So I'll close this video out.

I will add one thing little thing, the powerrating on the fixtures themselves; these days it's much closer but even now, they yellowlights use the most power.

And on the particular three that I have, redwas rated like 11 watts, green was 13, and yellow was 19.

So it's kind of interesting cause the yellow.



theparticular wavelength of yellow in stop lights is apparently not that efficient, cause itneeds a lot more power to produce the same brightness.

But with it being a yellow light it's onlyon at most six seconds at a time so I guess it doesn't really matter.

I may have wrecked a stoplight but I've gotthis neat Fresnel lens out of it–look at that! Can you see?.



Oh yeah, yeah.

So neat-o! Nifty, nifty, nifty.

So thanks so much for watching, please subscribeto Technology Connections 2, head on over to the original video if you got here withoutseeing it, and I'll see you next time!.

Leave a Reply