zipper on the side. The pocket for the electronic
stuff is attached to the waistband on the back
of the skirt.
A panel skirt design is a good choice for this
project; it’s easier to handle smaller pieces of
fabric while preparing them for the LEDs. The
outer layer should be about 1cm longer than the
mid and inner layers, to hide the white fabric at
the skirt’s hem when walking.
3. VELCRO, CABLE SLOT,
AND POCKET
For fastening the LED strips to the mid cotton
layer, you’ll cut 24 pieces of Velcro 2cm×1cm. The
soft, fuzzy “loop” side is sewed to the mid layer, 4
Velcro pieces per LED strip (Figure
C
). Using the
soft side here is important to avoid scratching the
fabric during washing.
Depending on the length of your skirt, you
can decide how many LEDs you want to integrate.
We used 20 LEDs per strip, so each strip is
about 33cm long. Two Velcro strips are placed at
top and bottom, the other two in between (under
the 7th and 13th LEDs, in our case). You can use
the strip as a reference for positioning the
Velcro on the fabric. We attached the Velcro
before assembling the full skirt, but it’s also
possible to add it afterward if you use an already
existing skirt.
The waistband is designed as a dual-layer
white cotton structure with access from the mid
layer to hide and guide the cables to the back
(Figure
D
). This also includes the pocket for the
electronics and battery at the back, which has a
buttonhole to access the cable from the inside.
Small black snap fasteners fix the two cotton
layers at the bottom to hold the cables in place.
4. PREPARE THE LED STRIPS
As mentioned, depending on the skirt size, the
number of strips and LEDs per strip may vary. To
keep the wiring simple, the easiest way is to use
a serpentine layout, so every output of a strip is
connected to the input of the next strip (Figure
E
). This allows the controller to drive all strips
with only one I/O pin. The only drawbacks are
additional connections at the skirt’s hem, and
a zigzag placement for the strips, which can be
easily compensated later in the code. Be sure you
can hide these connections at the hem, either by a
closure such as snaps, or a masking fabric layer.
If you want to avoid the hem connections, you
can wire all inputs at the top separately and use
multiple I/O pins on the microcontroller. But then
you’ll have to route 5 more wires to the pocket.
Before installing anything to the skirt, the full
LED arrangement can be pre-soldered. Wire
length depends on your skirt size; add some
spare length to account for movement. To secure
and strengthen the connections, add heat-shrink
tubing at the top of each strip (Figure
F
).
At this stage, I'd highly recommended testing
the LED strips with some sample code using the
NeoPixel or Fast-LED library, to check your wiring
before assembling the skirt. This can be done by
following Adafruit’s great NeoPixel guide for the
QT Py board at learn.adafruit.com/qt-py-and-
neopixel-leds.
Next, attach the rough “hook” side of the Velcro
to your LED strips to line up with the Velcro on
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