Colour-sensing clutch with Circuit Playground Express
SCHOOL OF MAKING
Made a hole in the wrong place? No problem!
Make a few more holes and create a pattern – turn
the mistake into a decorative feature!WIRING UP
Cut three lengths of wire – long enough to reach from
the holes you just made, straight down to the bottom
edge and over to the bottom corner of your bag. Cut
the wires a little longer than you think you’ll need;
we’ll cut them down later.
Using one colour of wire gives a clean look to
this build, and is a nice option if the wires in your
project will be visible, as they are on this bag. To
avoid confusion while you’re working, mark the wires
temporarily with tape. Colourful tape is useful here,
but a Sharpie and regular masking tape work just fine
too. Set aside your prepared wires, and let’s work on
that NeoPixel strip.
NeoPixel strips come in one-metre lengths (or
more), so you’ll need to cut it down with a pair of
scissors. Hold the NeoPixel strip against the flatbottom of your bag, and determine how many
NeoPixel LEDs will fit on your bag. Allow at least
1 cm of space on each end so that the strip can be
completely covered with tape later. Cut the strip
through the midpoint of the conductive pads, after the
last NeoPixel you’ll be using. Remove the protective
silicone sleeve from your cut piece.
Note the arrows printed on the NeoPixel strip:
this is the direction that data flows through the strip.
You’ll need to solder your wires to the beginning of
the strip, the end the arrows point away from. Strip
and tin the ends of your wires, and tin the pads of the
NeoPixel strip. Solder the wires to the strip: power to
5 V, ground to GND, and data to Din.MAKING CONNECTIONS
Insert the NeoPixel strip into your bag, and feed each
wire through its hole to the front of the bag. Refer
to the Circuit Playground Express to make sure the
wires are going through the correct holes. Once your
wires are fed through their holes, mark them again
with masking tape on the outside of your bag to make
doubly sure they’ll be connected properly to the CPX.
Secure the Circuit Playground Express in a set of
third helping hands, to keep it from moving around
while you solder. Tin the three pads you’ll be using:
GND and VOUT on either side of the JST connector,
and A1. Strip about 5 mm of insulation off the end of
the wires, and insert each wire through its hole on the
CPX from back to front. Refer to the circuit diagram
to make each connection correctly. For a secure
connection, wrap the bare wire around the edge of
the hole and solder in place. Trim off any protruding
solder or wire. You don’t want any pokey bits on your
wearable tech!ENGAGE CPX
We’ll use cable ties to make fasteners for attaching
the board to the bag. Small black cable ties work well
for this and won’t be very visible when the lights
are on. They’re also easy to remove if you need to
remove the CPX from this project later. You’ll need
eight cable ties in total.
Snip the eyes off four of the cable ties, and save
the long tails for another project (they’re quite useful
for applying tiny dabs of glue on things). These eyes
will lock the other four cable ties in place.
Pull the slack in the wires to the inside of the bag,
and lay the Circuit Playground Express in place against
the front of the bag. Align the CPX with the holes you
punched for GND and 3.3 V at the top, and A0 and TX/
A7 at the bottom. From the inside of the bag, feed a
cable tie through each mounting hole. Slide one eyeRight
Labels don’t have
to be colourful, but
why not make life a
bit brighter?The circuit for this project is simple, and can be used
in any project where you want to connect an external
strip of NeoPixels to your Circuit Playground Express”
”
Below
A third-hand-style
holder makes it
easier to solder the
wires in place