hi MJ with iFixit and today I want to
talk to you a little bit about the
proximity sensor in the new iPhone for
us the iPhone is an amazing device that
is stuffed to the gills with different
sensors and while we always make note of
the different sensors when we're doing a
teardown we don't always talk about
their specific function or role within
the device so we thought with the
release of the 4s we would highlight a
specific sensor that doesn't get a whole
lot of attention the infrared LED
proximity sensor for years the iPhone
just like tons of other smartphones has
had this proximity sensor whose job it
is to tell the phone just how close the
device is to your face this whole time
it's been bombarding your head with
infrared light the entire time you're
talking on the phone fortunately
infrared light is totally harmless but
I'm sure there are some people sitting
around in tin foil hats who might try to
convince you otherwise
the infrared proximity sensor largely
goes unnoticed primarily because it's
invisible to the naked eye you have to
rely on the magical powers of a digital
camera just to see the sensor in action
even trickier you can't use every
digital camera because many high-end SLR
cameras actually have IR filters built
into them we had to use a webcam to show
you the IR light emitting from this
iPhone so what's different about this
proximity sensor and the iPhone 4s in
all previous generations of the iPhone
the proximity sensor would only turn on
when something like a phone or a Skype
call was placed and then it would turn
off when the call was disconnected but
we noticed when the iPhone 4s came out
that our proximity sensor was working
overtime every time the screen was
activated the proximity sensor would
kick on take a look we thought this was
kind of strange why would this new
iPhone need to know how far away you are
from the device at all times and then we
thought about it for a while and
remember the iPhone 4s is newest feature
Siri so the Siri can be activated just
by raising the phone it's important that
the phone knows how far away it is from
your face at all times mystery solved if
you are craving more details about the
iPhone 4s proximity sensor head over to
the blog post about it at I fix it calm
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happy repairing