PROJECTS: KI T TY T WI TT Y
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2c. To electrically insulate the guitar wire from the wall anchor,
cut two ½"-long pieces of
1" heat-shrink tubing, then slip and
shrink them one by one over the wire at the lug end.
2d. Solder a 6" length of insulated solid-core wire (I chose red)
to the brass lug grommet, extended away from the guitar string,
and encase the entire connection in another piece of heat-shrink.
2e. Thread the guitar string through the underside of the hollow
wall anchor and screw in the wad of heat-shrink. It’s OK if it’s a
tight fit; my heat-shrink even twisted a bit, which made for a nice
fit. But make sure the wires and lug do not make any metal-to-metal contact with the anchor.
2f. While keeping the guitar string centered (I used a “third hand”
but you could have a friend hold it steady), apply some hot glue
into the core of the hollow wall anchor around the string. You
don’t want to fill the entire cavity, just a bit around the bottom to
further insulate the guitar string and keep it straight and secure.
If you add too much hot glue, the wire won’t be able to flex
enough to touch the top of the anchor, so err on the side of
caution and use only a dab or two.
2g. Feed the Ethernet and power cables through the hole you
drilled in Step 1b. Tie a simple knot to keep them from being
pulled out of the box. Position the Arduino boards in the box, plug
in both cables, and also plug the red wire from the guitar string
into its 5V header socket.
2h. On the lid of the box, solder a 3"– 4" piece of wire to one of
the anchor’s legs. Using a different color wire (purple here) will
help. The anchor draws a lot of heat away, so you’ll need to heat
it with the soldering iron for a while, or else the solder will bead
up and you won’t get a good joint.
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