How??

[Tropo-Bob (Bob)]

I have a new mobile phone and it records my number of steps and distance traveled. For the record, it was 9,300 yda. One day, I will get to 10,000 steps.

But how does it measure the steps? I can understand the distance with GPS, but how does the phone sense my number of steps? Its got me beat!

[The_bluester (Paul)]

Smartphones more or less all have accelerometers inside them now, my money would be on the software monitoring the accelerometers for the rhythmic movements they have identified as coming from footfalls.

[madtuna (Steve)]

If your phone is a Huawei and has a built in camera, there's a team back in China watching and counting your steps and reporting it to the Communist party who then notify you by email.

[FlashDrive (Poppy)]

Originally Posted by madtuna

If your phone is a Huawei and has a built in camera, there's a team back in China watching and counting your steps and reporting it to the Communist party who then notify you by email.

.... there's a little Como' critter on a treadmill in your phone ....

[gary]

Hi Bob,

As Paul remarked, all smartphones these days have accelerators in-built.

What is remarkable about these devices is how they are fabricated.
They fall into a class of semiconductor devices engineers refer to as
MEMs (micro-electro-mechanical systems). We just call them "mems".

They are literally tiny little machines with moving parts fabricated to
sub-micron precision which are then married to microelectronics.

For example, an accelerator in one axis might simply be a tiny, tiny
cantilevered beam, the movement of the end of which might be designed
to create a sensor where the capacitance changes and that in turn
transformed to a digital signal. If you fabricate three of these at
orthogonal axes, you get a complete 3D accelerator in a package just a
few mm across and that sells for $3.

Here is a scanning electron microscope of a cantilever resonating :-
https://en.wikipedia.org/wiki/Microe..._Resonance.png

A 1h41m video introduction on MEMs fabrication :-
https://youtu.be/EALXTht-stg

[Tropo-Bob (Bob)]

Thanks guys, that's amazing.

[multiweb (Marc)]

Originally Posted by gary

A 1h41m video introduction on MEMs fabrication :-
https://youtu.be/EALXTht-stg

This is the coolest video ever. I had no idea. Fascinating.
How do they make the layer patterns they project in the first place?

[gary]

Originally Posted by multiweb

This is the coolest video ever. I had no idea. Fascinating.
How do they make the layer patterns they project in the first place?

Hi Marc,

Masks or reticles are first produced using optical lithography, electron-beam
lithography or a technology called nanoimprint lithography.

To give you some sense of the geometry sizes on the absolute
state-of-the-art semiconductor devices, currently we are at
5 nanometres (nm).

Semiconductor engineers refer to these milestones in successive
generations of device geometry capabilities as "nodes".

I remember when the "node" was at 5 micron - a thousand times larger
than it is today - and we thought that was small.

Now the wavelength of plain old visible light goes from 380nm to 750nm.

So to produce semiconductors geometries at these 5nm nodes requires
an ants-pants technology called extreme ultra-violet (eUV).

Now this technology is so advanced that it is the type of stuff spies
would kill other spies for in James Bond movies.

And at the absolute pinnacle of this technology is a a company you
probably have never heard of called TSMC (Taiwan Semiconductor
Manufacturing Company).

Off-hand, I can't think of a more important company in the western
world right now than TSMC.

Actually, there is one other company. It's a Dutch company called
ASML and they make the lithography equipment for TSMC.

And this technology behind the technology of just how you make an eUV
flash of light is impressive in itself. It requires megawatts of power.

And there are a whole lot of other things that just don't work the same
way at visible wavelengths they also had to overcome.

Anyway these MEM's chips don't require eUV but the main CPU in
a state-of-the-art smartphone does.

You might find these videos interesting :-

A 5 minute introduction to photolithography :-
https://youtu.be/oBKhN4n-EGI

Inside TSMC (4 minutes) :-
https://youtu.be/Hb1WDxSoSec

12 minute video showing ants-pants eUV lithograpgy.
https://youtu.be/f0gMdGrVteI

[multiweb (Marc)]

Thanks for the links Gary. That's certainly not something that is common knowledge or has much exposure in the media. The engineering and thought process behind the manufacturing machines just dwarf the end product itself. That tin droplet concept is just mind-boggling. It is hard to wrap your head around how much time and effort and obstacles teams of people had to go through to achieve this in a practical and repetitive way. It also shows what humans are capable of achieving given the incentive. I wish we used that brain matter to solve more urgent looming problems but I guess market forces still drive the future. For now.

[Crater101 (Warren)]

They say you should learn something everyday. Reading these posts and watching the vids has been truly amazing, and has opened my eyes a little to the wonders of our technology.


Humble thanks!