Hi Why am I sitting in my car in a shopping centre car park? Well there's a very good reason for it is because the other month I tweeted a photo of a sign that they had just put up in the shopping centre car park and I'd never seen this before even though it's quite common in different our places around the world. But I saw this sign that says basically if you take one of the shopping trolleys out of the car park the wheels on them will lock and I posted a photo of the wheels and some people actually they'll said oh yeah we've had these those things for decades in their very shopping centre. but anyway this was a new thing for me. So I was interested curious about this technology and somebody actually offered to send one that they had one of these are self locking wheels and they offered to a send one in.

So I got it and I thought we'd take a look at it because it's a real problem. Take a look at this, you know? here's all the here's all the shopping carts there. they're all sort of just you know I find them in the dumpster room I find them scattered around the neighbourhood and things like that they're You know people take these things like just out of the shopping centre car park and they often like will walk to the shop and said oh they'll take their groceries home and then they'll just in the shopping trolley and then they'll just dump it and this is like a real huge problem apparently for costs like you know, many hundreds of dollars or something in in a lost trolley if you can't recover it. And I actually have fond memories as a kid of actually going around on the John Deere tractor they used and this tractor that then pulled one of the shopping trolley collection cart things and they'd go around not only the huge shopping centre car park but they'd go in the streets and everything collecting all these shopping trolleys because there was serious money.

So they go out and find them and have to bring them back and all. This is major cost, hence why some companies have developed these self locking wheel things to try and take them out, but it doesn't really stop people taking them out anyway. we'll go into our details of this. I Thought we'd do a teardown.

Oh, and maybe some measurements of these shopping trolly self-locking wills. This could be really interesting. Stick around and there it is. Will's Locke beyond at this point.

So they've got. What they've got is actually our coils in the road here. As you can see as the cars go past it, they're cut. These are coils in there and it's a magnetic loop based system and you can see that they're got them actually cut into there.

and but you can now get shopping trolleys out other ways via the foot cars and things like that so it doesn't really work. But anyway. I thought we'd check it out. So big thanks to the viewer who sent this one in that I have checked.

It does seem to be identical to the one that used in my local supermarket. so it's from my gatekeeper systems. This two plugs on the air bull. Why is that like a connector in a face or something like that? Perhaps war or find out, but it looks like we can take it easily apart with screws.

This one has had fair bitter use there, and this one doesn't seem to be locked because I can turn that. So yeah, both directions. no workers. So let's whip this thing apart and see what's inside.

There's gonna be like some sort of you know, solenoid locking mechanism or something like that. And of course there is going to be a battery inside there so it'll be like a latch in our solenoid so that it doesn't take power. of course when it's completely on. Otherwise, if it like switched on and had to take had to energize the solenoid coil from the battery.

it eventually died and then it had come good again. So so the first thing is what's inside these. Oh, there we go. Hello.

Nothing. That's weird. Okay, and nothing again. There's no hidden contacts in there or anything like that.

So what's what's the deal? So these are just self tappers. They're obviously not designed to work um, apart. long term. You know, a long life Lithium battery Lithium primary I would suspect.

And of course, there will be some form of big induction coil in here because that's obviously how that they're triggering these things. If you ride over the coil, it's not just gonna fall apart. percussive maintenance required trying to get medieval on its ass. Yes, this rubbers not bonded.

Here we go. I'm getting somewhere. Yeah, it looks like it's gonna eventually prize up. there.

We go. Really stiff, hard rubber. It's not. It's not quite a plastic, kind of a rubbery.

Paulo Myers plastic compounding thing I Don't know I've got no idea. But anyway, yeah, as I said, this one is not locked. This one will still spin. So presumably if I take it down there and pass it over the coil, it could actually lock assuming that it's a still functional of course.

Real solid monolithic block. Wow but it looks like the top cover comes off. And of course, these things have to be completely weatherproof as well. You know, either.

permanently sealed at the factory? I Did just have a thought of what these little plugs could be. There could be like little comms coils behind there. and because they're sealed so you might come out because they have different colors. There's a reason that they have different colored plugs like this.

You know, because you want to be able to I reset these things of course. Yeah, you take off the plug and maybe that just allows you to and then you just plug in there which has the coil behind it and that just accurately aligns and couples through to inside. perhaps? So yeah, that'll be my guess cuz it is all hermetically sealed. This sucker seems completely glued shut.

Okay I won't use the dremel I'll just hack away at it. And yes, this is the front cover for a scope. Makes a great tray. Yeah, it's looking like it's bonded at several points in here, so they pretty uh-huh Now we're starting to crack this puppy open.

Look at this and we're in like Flynn Well I haven't got the rest of it out yet. But anyway, we can see that the hi entire inner part rotates I didn't expect that. that's interested. Yeah, so it was somehow glued in I don't know.

It was a real pain to really get it off. It was a lot of effort that's for sure. Anyway, so this thing is supposed to eventually lock. Its does this drop out.

it just drops out there. you go. there's our battery. What are they? Oh okay, that's interesting.

Where's that big induction coil? It must be like I expected. Like a big induction coil around it. This is really fascinating. Looks like that entire inner section to sealed.

There's no screws and then this outer part. uh-huh That's how it locks I Suspect what happens. You see these ridges in here and like it's it's normally freely rotating like that, but it looks like this when it activates is going it. Eva This lever I suspect is going to go to one side and push out and expand this outer plastic and you can see how the plastic is going to get stopped if it expands out and with these little ridges, there's no way that it can.

It's just going to stop the whole wheel from rotating like that. So that's interesting. That's different to what I Kind of expected. so that's fascinating.

So I think that's what's going to happen there because this can only move to one side and if that does that, you can see how this is going to like expand out. It's designed to come apart like that. That's must be how it locks and then no surprises for finding jewel or ring seals. Either side here has to stop the water ingress.

Jewel A Ring seals is quite common with myself coming from the marine underwater background. Yeah, very common. Anyway, there's lots of science that goes into our rings. If you don't know, I'm getting the pressure right and the surface is right and all sorts of stuff.

And and no O-ring is going to be waterproof unless you actually grease it up either. You know, nylon type inserts in there. and I just had a washer there and that just yeah. it prevents water getting into this.

but even this, even if it does get inside here, this looks like it's a complete hermetically sealed package. Wow I'm gonna have to I'm just gonna have to Dremel this one apart as well. This is insane. Wow I Expected something easier than this anyway.

I Think what's happening here is we're probably going to have him, but this will be our Lithium primary battery. This will be our motor. It will have some sort of like gear reduction, you know, talk mechanism in there. There's a screw in there, some sort of lead screw kind of things, so once it's triggered, it'll turn the motor.

It'll you know, do a couple hundred revolutions or whatever it needs to do to turn the lead screw and then that will somehow push. Does that go through there? Although I can't see a hole in there, it's a bit weird. anyway. that'll push on this which will then separate these and lock the wheel.

It's rather clever. I guess is that a plug in there? Perhaps it really got to town on this? Unbelievable What? I'm seeing that's gonna lift out of there is it? And oh there we go. Plugs out and yeah, is our cog down in there? as suspected. pinky reduction mechanism.

okay again. I think they're glued that top plate on there. So once again, don't forget Medieval on it's us. Yep, a little bit of Dremel action there and I can start to crack this puppy open Oh Try not to damage anything, but can't promise it ultimately wasn't too hard.

Oh there we go. A bit fancy pantsy. Oh See an antenna Wow that's not a that's not a loop I Was expecting like a low frequency. like a like hundreds and hundreds of turns of like a low frequency magnetic loop in here.

Once again we've got access to the PCB but check it out. there's a motor in there. We've got some silastic in there. Somebody had fun.

There you go. So they dumped all that up programming port there for the micro. It's oh, there's a motor under there. Wow, it's all ridiculously sealed and that's going to be our lithium primary battery guarantee.

Yeah, that's a lithium primary but that's all we've got. Wow I Don't see any magnetic coil I mean you could just do it with it like a Smalling doctor if you're pumping out enough cuz that's like Bluetooth E-type well that's a TI CC 2510. It's upside down so all the electrons are gonna fall out. That is a 805 one micro with embedded 2.4 gig RF in there.

Hence why the antennas there like there? What? Okay everything everyone told me about these systems and a few other things that I looked at were yeah, these are like magnetic loop based systems. Like low frequency stuff. Um, as you'd expect like buried in the ground, you'd expect them to be a magnetic loop based system. So I don't see anything.

It got an external crystal here. We got some trends over here. that would be for driving the motor, so probably like a half bridge for for driving the motor. Perhaps if you a few more over here a whole bunch of stuff over here.

these two pins over here. The battery wires are buggering off up there somewhere, so is that maybe in there? Perhaps they have a magnetic loop and it's just like got a discreet gain stage there or something like that. What's that job'? Is that a voltage regulator or a little five pin? SOT 23 Op-amp perhaps? Alright, so assuming that this is going to be a magnetic loop based interface here, this makes sense cuz look this then as a parallel resistor to ground there, then a cap, then it goes into a bunch of here. So that's some sort of discreet amplifier.

So yeah, I'd say that's got to be the magnetic loop interface and then just for other comms. Shop owners would be supplied though as part of the system so that they could do-- reset, lock, or unlock the wheels. So maybe I'll find some info on that and take the board out. Surprise surprise, there's the inductor on the So yeah and nothing special.

all they need. It's just an ordinary inductor there with you know enough tunes to pick up the magnetic signal from the loop. and Bob's your uncle up. There's nothing on the bottom there code as I said.

like the code to turn this off and on could come via the RF interface. but of course out in the field you don't want that because these things are buried under the ground so you've got to have like a manic loop based system. Otherwise you know if it was an electromagnetic signal then it's not gonna penetrate the ground. So you need magnetic loop based a system at low frequency and that's what you're going to get with the coil there.

So that's just a you know, a multi-stage a discrete amplify our front-end for it. You know is this thing got any encoding at all on it or whether or not it just sends out like a fixed like 5 kilohertz signal or something. Maybe I should actually put like a coil near this and just uh sweep it, see what happens. So let's just check this battery here.

I'd Expect it to be good because it's gonna that micro is gonna take naff off and yep over there almost three point one volts there so that is still this is still good to go. I Mean with a large capacity lithium primary body battery like that, this thing is going to last like the shelf life of the battery. You're going to get 5 or 10 years operation of this thing assuming that the motor doesn't Drive Of course when you drive the motor to a lock or unlock this thing, then that's obviously going to take a significant current from the battery. but if it's just like in standby, yeah, you probably get the shelf-life of this battery.

These and micro runs are the sniff of an oily rag. Totally crude, but I am probably not gonna be effective. but I'll give it a go anyway. I start from 500 Hertz like a hundred Hertz increments knowing kilohertz? Nope.

Evo encoded and or it's not how I amplitude enough. Ah with a shot Now I know this is crew des, but I'm gonna go out there and try and actually detect the signal from this thing. What I've got is a pair of headphones here that I'm actually using as an external microphone input to my Zoom H1 recorder here, going to set it for 96 kilohertz, 24-bit recording, and of course speakers you can actually use as electro dynamic microphones. That's essentially what they are.

Um, I guess you can see like when I talk into it, you can see I'm actually and if I put more if I touch it there we go. we're gonna max it out on that so it's crude, but should be good enough for Australia. Let's go. So there you have it.

Our crew das Ozzie Dynamic Microphone actually did the business and we picked up the signal. It's not perfect, but we can definitely use this to analyze and possibly replay this as well. You can see there's bursts in here and we're so it's basically chirping like like twice or three times. There's twice a second.

something like that. Here it is ChIP Chip chip chip nice. And if we actually zoom in on one of those packets, there you go. it's actually encoded and it looks like so this could be like a stop-start bit like 1, 2, 3, 4, 5, 6, 7, 8.

We've got so a start bit 8 data bits 1 stop bit. By the looks of it and it looks like the length of it here is determines whether it's a 1 or a 0. So it looks like you know it would take your pick either way. but you can see that there are like let's assume that this is a 0 and then we've got 4 ones and then possibly three zeros like that and then now stop it And that's just easy for any you know the mic on board micro to interpret that and then if you zoom in closer to here, you'll find that this is just a single frequency there.

There you go. That's the sample. That's a 96 Kilohertz sample right there. but they're all basically it.

The frequency does not change. So what what we can do now is actually just analyze this and have a look at the spectrum plot. Tada and there's our peak right there. Seven thousand, Seven hundred and fourteen.

Hertz That is terrific. There you go, and again, these are just little harmonics out here. Don't worry about that. So yeah, it's just that one fundamental frequency and the length of it determines the packet essentially.

and it looks like it's exactly the same packet every time. Yeah, it's just going lock lock lock lock. So obviously there'll be an unlock command as well. presumably unless it's only done via the RF interface.

which I doubt I Think you can actually do it via the induction beauty. And there you go. If we just plot the spectrum of just the one burst there, it looks like that's peaking at seven thousand, Nine Hundred and Fifty-three Hertz there. And it's amazing what you find on the FCC website because when they get this EMC tested, of course they have to get at FCC compliant and all this stuff is on here.

Turns out it's a very old design. In fact, we didn't even have to do a teardown because the internal photos are all here here. We go. Here's all the internal photos.

Does that look that's different. That's different. Our one. Yeah, that's a different design.

so this is an older design. But anyway, this shows you. There you go. That's that.

Lithia Cr123a Lithium primary I Think might have a bigger one in here now. But anyway, yeah, the motor, the gear reduction making is a very similar sort of thing. And there it is. So yeah, the FCC is a good website to do.

it. Looks like it used exactly the same thing. Yeah, it was basically back in the 2000s, so this was actually back in 2000 and seven. So it's a pretty old design.

They've obviously updated it since then, but you know, here's the confidentiality. Let are the coverlet, internal 4mp, any calculations, the tests report for it, and anti drug abuse authorization letter America. So there's tons of stuff there, including the actual training manual. and here's the cart.

Key thing. This is what the shopping center would get. and yeah, just lock unlock and a table. It tells you you like to bring it towards it so it does.

I Think it does use the RFR system. so your copyright 2007 so I'll link to all this down below. We won't actually go through the whole thing, but it's very comprehensive. It's a hundred page manual and tells you how to like install it installation philosophy with the photos and everything.

it's really exit manager stuff like that. It really is quite a remarkable. The detail that they've gone into: I'm not sure if this is available on the website and here's how you might typically like lay out a shopping centre car park: You go around the perimeter of the car park, but as I said like it's so easy to get trolleys out of these. they're just everywhere.

the limit of the just driving out there tonight. like there's dozens and dozens of trolleys outside the area and I'm sure all the wheels are fine. all the ones I find in the dumpster in because people use go borrow the shopping trolley they take stuff down from their office to dump in the dumpster room. I Find stuff in like actually in trolleys.

very convenient. I Can just roll it up to the lab. you know it's not nice but yeah you just go out via the footpath or whatever. It's not stuck rocket science.

But anyway and here it is. They tell you how to saw, cut the grooves in there and place the let's the cable in there. They even tell you what type of cable to actually use as well. They got like datasheet so there's the transmitter circuit board there.

it is everything. It's all in here so it's it's fantastic. I Love it Here we go. How to solder the splice installation photos, scotch coat sealer and I put the heat shrink and here you go.

Here's out the trenches and here's how to seal em back of cheese. That's a bit how you doing that one but you know that one looks ok once you clean it up. they've gone to town. Really? that's the caulking gun to seal it all up.

Quikrete Fantastic. And there you go. How I paint big yellow lines. They haven't done that at our car park.

it's It's more subtle than that, you just don't know. They've just got the sign there. But yeah, we've got flow charts and we've got everything. This is great here you go.

Here's the material specification sheets the the cable for those playing along at home. For you cable aficionados, There you go. the building twisted-pair cable great stuff. Gate keeper systems, loss prevention with a focus on your shoppers experience experiences everything, cart retention and all sorts of push out prevention.

It's called there you go that's the industry term, push Out and Pink Card analysis. They support 47 of the 50 largest retailers in the world. Wow. I guess there are a Walmart and all that sort of stuff and the average push out 50 is five hundred and sixty bucks.

That sort of cost to either replace the trolley or go out and find them and and stuff like that. So yeah, it's actually preventing all that, so trying to protect it. But ultimately these things like they don't work like people is just gonna eat. It doesn't stop you pushing them.

Even if the wheel locks up, you're just like just drag it. It doesn't like it's only one wheel. They don't do all four wheels. It's only or let us know down below if they're what, they do it.

your shopping center. but the ones here, it's only on one wheel. So Whoop-dee-doo what's that gonna do? Alright, now that we've got the recording on here, I'm gonna plug the same headphones instead of the Mikey I'm gonna plug him into the headphone out and see if we can play back this signal and actually get this thing to lock. Fingers crossed I Like I Don't know if it's gonna have enough power like I may have to amplify it, put it through a larger speaker or some sort of coil.

but anyway, give it a bowl. All right. Here we go. Nope, obviously not.

It's not close enough, so not good enough. Let's try the speaker on the end. not good enough. What might want one? Nope.

Okay, let's try an external power amp and a bigger speaker. but we need a bigger boat. But yeah, I think ultimately we're going to need a coil to do this. like as in not a speaker coil but a just a regular coil.

Here we go. Okay, let's just try a direct connection ground that still nothing Know it? Zip a Dee dude I increase the level what won't want? wha Worth a shot. But anyway, our the point of all this is that you could potentially you replay that signal because it's pretty simple and do some nice social fun social engineering perhaps? not that I recommend that, but you know it could be fun. So there you go I hope you found that as fascinating as I did.

This thing just popped up randomly in my local shopping center I wonder how does that work? Now we know terrific stuff. so if you like that video, please give it a big thumbs up. As always, comment down below and subscribe on my library Channel I'm like aw, I'm gonna get to 10,000 Like real 10,000 subscribers really shortly. It's just going nuts.

So yeah, check that out. down below the forum. all the usual stuff, you know? Yeah, catch you next time.