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How (Not) To Build A Power Meter | GCN Factory Tour With power2max


– Power meters are one of
the most technical components on a bike, and how they’re made
is a closely guarded secret. However, we have come
to a rather lovely part of rural Germany to the HQ of Power2Max ’cause they are gonna
show us how they do it. This is how you make a power meter. (speaks in German) – Sorry, I’m really sorry. Now, a little bit of
bad news, unfortunately. At my first day of work, they said, “Company breakfast is at 9:00,” so we’ve turned up at
9:00, but it turns out they’ve already been
working for two hours. Apparently, everyone starts
work here at 7:00 a.m., so we’re a little bit late. (rhythmic techno music) Now, step one, and I’m already excited, and we’re only at the storage, okay, this is like next-generation shelving. The bulkiest part of the power meter of course is the aluminium spider and seeing as there are lots of different iterations for different cranks and
different chainrings They are all stored in here. It’s an automated shelving system. Okay, so first of all we are
going to chose the right one. I’m going to go for 110BCD on here touch this button. Look at that. There we go. Number five. There we go, check it out. Little things, eh? Now, step two of the process Is again hopefully relatively un-technical but again it involves laser
beams so I’m even more excited So what we are gonna do is
is very simply etch on there things like the logos but also the bar codes that
each have that is traceable and then actually things are gonna help the manufacturing process. So those little holes there
they need to be prepared for the stain gauges to then be attached and also little lines
are gonna go on there to help with collaboration. Okay, ready? Then we need to switch on the fan, switch on the extractor fan and then I press go. Whoa laser beams (upbeat techno music) There we go, check it out. Hopefully that’s gonna be
traceable to me, specifically. But ah, yeah. My first
laser etched spider. I know that’s probably a bread and butter process to many of you watching but to me that is generally thrilling. Cleaning, super important, wanna see? (air compressor blows) Right for this next stage of the process. I need to take a seat because things are getting
really serious, okay? So at this point I need to
glue on two strain gauges on to our freshly prepared aluminium spider and it is incredibly important because if you don’t do it correctly then the power meter isn’t
going to work properly. So to put it in some kind of context the way a strain gauge works is it’s got a little wire
that runs through it. And you measure the
resistance of that wire. And then as the aluminium flexes then the resistance of the wire changes because it’s simply changing length. But we are talking tiny numbers here. So, the wire resistance is
about 350 OHMS, so I’m told. And if you were then to ride
at 100 watts at a cadence of 90 the difference detected in
that strain gauge is just 20 parts per million. So someone has already
done the maths for me. That just naught point naught
naught 7 OHMS of difference. So, you can see, this is actually a pretty
skillful part of the process. All there you go, okay, now
blow out any kind of air bubbles all there we go, oh my goodness mate, I got air bubbles all over it, Can’t really see. I’m pretty sure I nailed that. Do you guys want to check my handy work? Give me your mark out of ten. – That’s not good. (laughter) – Right, one more chance. More glue, more glue. Take two. Zero out of ten, aww. – Ugh… – Now fortunately someone
has drawn at least some way saving my very poor craftsmanship
on the glueing stage. Now I got another highly skilled job that I’m probably going to
fail miserably at as well because we need to obviously
attach our string gauges to the circuit boards so we basically need
to solder the wires on. Before wires go anywhere near it though we need to pre-solder so
another difficult step. Wish me luck. Flux, flux first, flux
first, always flux first. I’m going to put more
flux on than I did glue. Hopefully that’s the right thing to do. Oh wow weird, how cool is this? I have a feeling this is
melting the strain gauge Marks out of ten please? – Hmmm… Eight?
– Eight! Ah yes! These are all wires that we
attach to our strain gauge and into the PCB. Now they are actually
being cut by a machine because the length of them
is incredibly important. As we just learned we are resisting so longer wire are going
to provide more resistance so that’s gonna throw
the strain gauge off. So it’s all really quite precise. (techno music) Alright I solded. I’m gonna keep going
I’m gonna go white now. Alright that one is solded as well. Okay I’m ready. Let’s go for it. (laughs) No? One? Naught? – Zero.
– Zero? Okay so now a change of scene now leaving my woeful soldering probably in the bin somewhere. We are now programming and
checking our circuit boards. Okay so these are printed
just down the road couple hundred K’s away
still in Germany. And these ones are actually
from the type S power meter. So the new ones the NG and NG
Eco are much much smaller. But this is really good to illustrate some key points on here. So, we got our accelerometer
just tucked away in there then we got our temperature
sensor somewhere down there not quite sure. We got a little radio transmitter there. And then we got our sensor
processor there, okay? And what we are gonna do
is pop it in that machine and scan it first, so we got that whole record of
exactly where it comes from. And then pop it down and
that is going to programme it and check it. Okay, so hopefully, hopefully
I can’t get this one wrong. Okay, shut the lid. And there are three
PCBs can do their work. Okay look, checking it. Done, done, done, pass, done. Yes, looking good. There ya go, that’s what we like to see. 100% success rate. No soldering needed, all passed. Now we are going to stick our
PCB into our housing here. This is the housing for the NG Eco. So the new one. Alright so we need to
line those two points up with our battery connector. Alright soldering time. Wow, wow at that! That looks pretty good to me. Okay, you ready, no? Oh that doesn’t sound good Yeah, that didn’t sound good. You know it’s getting really good when we have to put safety specs on. This part of the process. I’m gonna say it, it’s
completely taken me by surprise. I didn’t know it existed. What we’re doing is we are going to seal all the electronic components in a polyurethane rubber and it is applied in liquid
form though that bit there. And we seal the whole thing, cover it up, and then it goes in an
oven and is then cured. Making the whole thing completely
and utterly water proof. And I need 11.5 grammes polyurethane and everything is quite hot
and a little bit dangerous. Okay, you ready? Quite proud of that. Ready for use under
water or in Great Britain. Quick change or location and
now in the test lab okay? This machine behind me is a dynamometer, and what it does is it can dynamically
calibrate the power meter. So in there you got a motor and this point here this is
the calibration reference box and that’s accurate to
naught point one percent. So that’s like super,
super duper accurate. Then of course we got our power meter and then behind our cassette here we got a brake which
generates a known resistance so use all of that we
can tell whether or not the power meter is moving perfectly. Okay, first off, programmed this all myself
just a little bit earlier. There we go. So, the power meter that
is in there at the moment is an NG Eco. Normally it would be a
power meter NG that is in there. Every single NG unit comes up here to this
dynamic collaboration. Because the unit is accurate to one percent it needs the
accuracy of this machine to make sure that each one is perfect This one though the NG
Eco that is accurate to 2% So normally that is collaborated using a static collaboration and then one out of every batch so one out of ten power meters will come up here just to make sure the static
collaboration is working. So then it is run through this
extra extra precise machine. Right now we can see here
the profile of the test. So that red line there
is what the software is telling the motor to do and that blue line is coming from our collaboration reference. So that is the one that is accurate to naught point one percent. And that is the one
that we can now measure a power meter off just to see whether or not those two traces match up. So there are plenty of unboxing on GCN. But I think this could be the first time we are actually gonna
get to box something up. However, this might not be
the last stage of the process but one more thing to do before that. First thing we need to clean up our power meter just to make sure it is in the kinda condition you
would like to receive it in then you are gonna put a battery in, seal the battery compartment up then very important, we scan the bar code then that is gonna give you a tracer, registration of your power meter and is also gonna print
something out that means you, the owner will know that
it has be collaborated. Then, then it can be put in the box. I guess the last step
in making a power meter if you are gonna sell it is actually packaging it up and shipping it out. And I have an order right here. It’s not going very far, I don’t think but I’m gonna pick it and then maybe throw in a little GCN swag. So I need a type S for a rotor power meter it’s got a bonus seal kit black and red colour GCN colours. I like it. Fitting tool. And one last thing stick a GCN t-shirt in there for you as well. There we go, now we’re cooking. We’re back now at one of my
top five storage solutions of all time. It’s not just the raw
materials that are packed away in here, it’s also the
finished product as well. And I’ve been asked to
scan that little code there and then apparently something
cool is waiting for us. I like cool things. Hello what have we got here? That’s what I like to see GCN. That’s a nice NG. Aw look at that! The laser etching machine
has done it’s stuff look at that, the GCN NG Eco. One of the first off the production line. That’s amazing. Fantastic. Well I think it’s pretty fair
to say that I’ve left quite the trail of destruction
in an otherwise pristine German engineering facility but don’t worry they kept a close eye on literally everything that I touched. Now, in all seriousness I would like to say a big
thank you to power2max for showing us so much detail hopefully you’ve learned as much as I have even if quite clearly, like my soldering, it would take an awful lot more practise to be able to do it for real. Now, do make sure you subscribe to GCN before leaving this video. It’s very easy just click on the globe. And if you would like some
more content right now you can check out
mountain bike versus road just down there. Or see inside an NG power meter
from an unboxing perspective click, just down there. (speaks in German)

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