3

FORGE

ADD THE BATTERY HOLDER
Since the battery holder is a rigid, flat piece, we’ll
place it on the side of the hat so it will be against the
flat part of your head. Fold the edge down at one side
of your hat. Place the
battery holder so that its
opening points toward
the edge of the hat and
the negative sew tab is
on top. Use a dab of hot
glue to tack it in place
for now.

SEW THE CIRCUIT
Now that we have our components tacked in place,
we can sew the circuit to connect them. Thread your
needle with about 50 cm of conductive thread and tie
a knot at the end. This may feel like a long piece of
thread, but we want to sew each leg of the circuit in
one continuous run.
Start at the battery holder: begin your run by
stitching four or five times around the positive sew
tab of the battery holder. Pull the thread snug against
the sew tab for a good connection.
Use a simple running stitch to sew to the positive
sew tab of the first LED. Loop around the positive
sew tab four or five times, pulling snug each time.

Continue sewing this leg of your circuit, and connect

to the positive sew tabs of the other two LEDs in the

same manner.

When you’ve connected the last positive sew tab,

tie off your thread with a tight knot. Trim the thread

close to the knot to prevent short circuits.

Rethread your needle with another 50 cm length

of conductive thread. Go back to the battery holder

and repeat this process to sew the negative leg of

your circuit. Keep this second thread run at least 1 cm

away from the first.

LIGHT IT UP

Now, slide a coin cell battery into the battery holder.

The LilyPad sewable battery holder has a handy on/

off switch, so turn your

project on and try it

out. The battery holder

should sit comfortably

on the side of your head,

and no conductive thread

or component should be

touching your skin.

If your LEDs don’t

light up properly, check

to make sure they’re all aligned correctly with each

other, and that the battery holder is in the same

orientation: negative sew tab on top. Also make sure

your conductive thread tails are trimmed to prevent

shorts, especially at the battery holder.

Your author doubled the LED magic by repeating

this process on the back of her hat with red LEDs.

How will you customize this project and make it your

own? Show us your build at @HackSpaceMag!

YOU’LL NEED

Knit Hat (find one

with a folded cuff)

3 Sewable LEDs

1 sewable coin

cell battery

holder

3 V coin cell

battery

Conductive

thread

Regular sewing

thread

Wire cutters

Needle, thimble,

scissors

Hot glue gun and

glue sticks

Once you’ve gotten the

basics down with this project,

you can use this circuit

to sew LEDs into other

garments too

”

”

Above

The battery holder lives on the inside of the folded-up part of

the hat, its unsightliness hidden

Below

The battery holder should go along the side of the hat, where it

will fit along the side of your head.

Below

White LEDS at the

front, red at the back

WEARABLE TECH