Smart backpack with wireless charging pocket
FORGENever run out of power while out of the house again
Smart backpack with
wireless charging pocket
any mobiles now come with
wireless charging capabilities,
allowing you to charge your
phone by simply placing it over a
base – no cords or plugs needed!
But what if you could charge your
phone while out and about by simply slipping it into a
pocket? In this project, we’ll add a wireless charging
pocket to a backpack for holding a portable Qi charger.
A portable charging bank is also a great source of
power for wearable projects, so we’ll add a strip of
NeoPixels to act as a visibility light and status bar. The
light will glow when the charger is on, so you’ll know
when power is flowing!
Wireless chargers use resonant inductive coupling
to transmit energy from one magnetic coil to another.
The coil in the charger is the transmitter, and the coil
in the phone is the receiver. While there are several
standards for wireless charging, ‘Qi’ is currently the
most widely adopted standard, and you’re likely to
find many portable wireless chargers labelled as ‘Qi
Chargers’. Most of these chargers come with USB
ports for plugged charging, which can power a 5 V
microcontroller like an Adafruit Trinket M0. So, how
could we resist adding some NeoPixels to the mix?
If you have a newer Samsung phone or iPhone,
your phone may be Qi-enabled and ready for wireless
charging. If you have an older phone that doesn’t have
Qi technology built in, there’s good news: you can add
a wireless charging adapter pad to your phone! These
adapters add an adhesive receiver coil to the back of
your phone, and plug into your phone’s charging port.
They’ll work just fine for this project!
The wireless charging pocket will be visible from
the outside of the bag, so you’ll want to choose
fabric that will co-ordinate well with the design of
your backpack. Fabric with a little bit of stretch in it
will work well here, as the phone needs to fit snuglyinto the pocket so that it is held tight against the
charger. A sewing machine will make quick work of
the pocket, so use it if you have one, but hand-sewing
is fine too. When attaching the pocket to the bag, you
will need to hand-sew it in place if the location you
choose is inaccessible by sewing machine.
Cotton bone casing is used in corset making to
hold boning in place on the inside of the corset. It’s
a great material to have handy when using NeoPixel
strips with wearables, because the standard NeoPixel
strips fit inside perfectly. The silicone weather-proof
strip that NeoPixels come with is a bit tricky to attach
to fabric, but the cotton casing is easy to sew or glue
to fabric. If you can’t find corset bone casing, you can
make your own casing by sewing a strip of cotton into
a tube and ironing it flat. Bonus: white cotton casing
diffuses NeoPixels nicely into a glowing bar of light!Adding a microcontroller gives you lots of options
for adding ‘smart’ functionality to your bag. We’ll use
a Trinket M0 and NeoPixels from Adafruit to make
a pulsing blue strip of light, perfect for visibility at
night, or just adding a bit of sci-fi to your outfit. We’ll
program the Trinket with Circuit Python, and you
can easily update the code when you think of a new
feature to add to your bag. For protection from the
elements, all electronic components will be located
inside the bag, and it’s a good idea to spray the
NeoPixel casing with a protective hydrophobic coating
like Scotchgard.M
Sophy Wong
Sophy Wong is a
designer, maker,
and avid creator. Her
projects range from
period costumes
to Arduino-driven
wearable tech. She
can be found on her
YouTube channel and
at sophywong.com@sophywongThe wireless charging pocket will be visible from
the outside of the bag, so you’ll want to choose
fabric that will co-ordinate well with the design
of your backpack”
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