tonight's video is assisted by a roundabout English dark mild ale from
Torque brewing here in Winnipeg they call themselves the mechanics of beer uh 21
IBU nice and low not too bitter reserved nutty be spoked malt forward mm-hmm
tasting the malt tasting the roastiness very nice not tasting the be
spoken ness.. whatever it's craft beer it's all bespoke beers now
tonight's amusement is a teardown of this little thing that I found in the
dollar store it's called blink steps and what it does is that every time it gets
bumped they're supposed to be for tying to your shoe laces so that when you're
walking or jogging or whatever with every footstep it does that but what do
we see here they light up as you move on trade you aces and rethread with wink
steps added to the laces we recommend one pursue if you bought only one pack
right okay roughly 15,000 50,000 flashes of light
before the battery feeds batteries included batteries are inaccessible and
not for replaceable not water-resistant keep away from open flame not intended
for young children uh-huh so let's get in here and see what's going on first
thing you see on the back is there's two batteries see what those batteries are
not easily the bigger the nail r44 hmm and smaller than Co 22 cr2032 so I'm not
quite sure what they are exactly actually yeah they might be 357 okay oh
that is which is also called LR 44 what was I thinking of always thinking of
your 26 is smaller ones right anyway this might be what they are and it looks
like they're spot welded to each other so they're not salvageable
that would also make it really difficult to replace if you were to crack into the
thing so other than the batteries what are we expecting to find in the inside
here some kind of a vibration sensor there's a couple of different cheap
types that I've seen from China one is just a metal can with two studs on the
bottom and a loose ball bearing in it that just splashes against the mix
contact the other one is a metal cylinder which is one contact with a
little kind of spring down the middle that's the other white contact and when
it gets jostled that bashes like that not sure which one but that's probably
what that little cylinder is up the middle there then we've always got to
50/50 style LEDs which have you can see it in there as they fade out three chips
each but you can kind of see contacts in there three contacts at the top three at
the bottom so there's three in parallel which makes sense because we've got
three volts ish there and a white LEDs gonna be three ish bolts forward current
there forward voltage so that's probably what's going on there I'm guessing by
the way they fade out I'm guessing that there is a capacitor in there that this
little switch charge is briefly to the batteries but I'm also seeing just
through there what looks like a little transistor so I'm not quite sure what
that's all about time to crack one of these guys open
not sure it's obviously glued shot so I think you have to get a little bit
violent much is fine I wasn't expecting these to go back
together anyway
well I've rather burst it and that wasn't welded on I was wrong
so theoretically those batteries could be replaced okay now what are they
really lithium CR 1220 oh so there are
different than anything of god they're much thinner than these 357 s but they
are the same are almost not that pretty much the same diameter alright so being
with him hang on what's the voltage on those then is that's not going to be the
one and a half volts plus one and a half volts that I thought it was yeah that
one's three so this is a six volt circuit huh
let's you stack those guys in series
yeah that's going to be a six volt circuit okay so I'm wrong already let's
see what we got on the board here so there's the vibration sensor you notice
there's one way or going up the center and the other electrical contact is the
outer shell that's going to be that one that's set up like this what else we got
in here we have a capacitor we have the two LEDs and then we have one resistor
and one transistor of some description transistor is a j3y to look that up and
see what I can find about that but I'm assuming it's nothing too special so I'm
going to go and look that up and I'm going to pause and see if I can draw
this out no that wasn't that hard to find actually there we are g3y
which is actually MMS it'll five-hole NPN transistor so what do we got here
collector current half an amp base collector voltage max forty volts yeah
this isn't going to exceed that frequency hundred and fifty megahertz
yeah it's just your basic little transistor nothing special you're
probably dropping just about any NPN in this circuit would work just fine so I
decided to look these these things up just to see what they actually sell for
when they're not at a dollar store and holy hell 13 pounds 61 or 51 75 in
whatever that currency is apparently that currency is amaretti durum which is
eighteen and a half dollars Ken me begin bloody hell who else is selling though
how about eBay really guys 17 bucks 15 bucks plus 22 shipping or five pounds 95
on this gifting gadgets store okay hmm I wonder if the any of these people are
actually selling them or if they've just got them in their shops cuz I can't
imagine anybody paying that much for them or that much of course if I was to
buy up the stock that the dollar store has and sell them to the UK market too I
probably still lose money on shipping okay the reverse engineering is done and
it's pretty similar to what I thought it was going to be just getting here a
little bit later so we have the six volts from to three volt lithium
batteries in series we have the little springy vibration switch we have a
capacitor which is about 7,000 nano farad by my measurement anyway and I
think well that's measured in the circuit so some of this stuff might come
into play we have a resistor which is 3.3 K we have the NPN transistor so wind
oh and then we have the LEDs so when the switch makes contact it puts
this capacitor in peril with the batteries and charges that to the full
battery voltage assuming that stays closed long enough which it should get
it's well its own low resistance path to the batteries that should put a voltage
spike on there anyways so that then discharges through the base
resistor the base emitter Junction and through there through the diodes but it
also by doing that through the base resistor turns on this NPN transistor
which is gonna stay on until this drops below about 0.6 volts give or take
that's the base emitter Junction voltage so when that happens when the transistor
gets turned on basically it becomes a low resistance path from collector to
emitter collector is at the full positive voltage so it's passing that
voltage through six volts through to these two guys in parallel and awaits
them up the normally six volts would be enough to make to make these LEDs
explode however these batteries have enough of
an internal resistance that it's not going to be a big deal and it also
doesn't stay at full voltage for very long as you remember and you whack these
things they fade down pretty quickly and as this voltage starts dropping this
transistor is going to stop being fully conductive and moving to its linear
range and as you can see them sort of dimming as this capacitor discharges and
then they finally shut off again so when there's nothing happening when this can
this switch is not closed and when this capacitor is discharged the current draw
of this circuit is going to be essentially nothing just whatever the
leakage voltage of this or the leakage current of this thing is which is by
design transistors when they're off they're off
so that's uh those battery should last quite a while and that's why they get to
claim on here that this single last 150,000 flashes because it's not using
very much current about those batteries cool little circuit actually you'd
implement that with the switch as just about anything it can be any kind of a
momentary switch it could be a reed switch sensing your bike tire spinning
so that it flashes once each or it starts the fire sequence once every rpm
your bike there that could be interesting um what else oh yeah when I
was looking closer at this thing I noticed that you could actually see the
little spring in the middle of this that makes contact and when I want to whack
this thing you see it we were wobbling around in there so it's not making a
very hard contact but it doesn't have to a simple little circuit and a pair of
them for a buck how can you go wrong with that especially with the prices
that they're charging or that that actual retailers are trying to charge
for these things they got a couple of batteries out of the deal that I didn't
have previously that's always neat they don't know what I'm going to use them
for but you never know and maybe I will put this on my hiking boots that I wear
when I'm walking the dog at night know that winter's coming and night is coming
a lot earlier well I hope you found that at least a little bit interesting I like
I always like the challenge of reverse engineering something and that's a
pretty simple little circuit well yeah thanks thanks for watching comments
questions down below as usual and I will talk to you later