PROJECTS: BEATBEARING
makezine.com/17/beatbearing
4. BUILD THE ELECTRONICS
NOTE: For all wiring, follow the schematic at makezine.com/17/beatbearing.
4a. Solder wires about 10cm long to
the 2 solderable D-sub connectors.
Use a contrasting color for the ground
wires, and don’t bother with the 4
unused pins.
4b. Connect the 4 ground wires from
the D-sub connectors to 1 edge of the
solderless breadboard, establishing
a ground rail. Use another wire to connect this rail to the Arduino’s ground
terminal. To hold the breadboard next
to the Arduino, I taped both to a piece
of cardboard.
NOTE: With IDE cables, you
don’t need to solder. Plug
the 3-connector cable’s
center connector and one
end connector on opposite
sides of the breadboard
trench, offset by 1 hole
(see diagram online).
4c. Connect the 5V line of the Arduino to the breadboard along the opposite side from the ground, creating
a 5V rail.
4d. Plug the 2 multiplexer chips across
the breadboard’s central trench and
connect them up to the switch wires
from the D-sub connectors. With
HEF4067B chips, the 16 independent
inputs Y0–Y15 run from pin 2 to pin 9
on one side and from pin 16 to pin 23
on the other. Don’t worry about the
order; comments in the software
explain how to sequence the washer
inputs there, which is easier than
untangling and continuity-testing all
the wires.
126 Make: Volume 17
