Have a Safe and Sane
■ FIGURE 4.
layout of the
board which is
Halloween night provides a great opportunity for
frights and fun, but exercise care, too. The Arduino
Halloween shirt is intended to be constructed by adults
or with adult supervision. Young or old, be mindful of
wearing dark clothes when going trick or treating.
If your Arduino Halloween shirt is black or some
other dark color, consider adding reflecting strips on the
back, so that passing motorists can better see you (or
your child). Overall, a white shirt is safer for children,
even though it may not be as spooky looking.
cutting it to the size I needed.
Notice the female headers on the board. These
connect to a row of male header pins soldered onto the
analog pins (pins A0 through A5) of the Wave Shield. The
Wave Shield doesn’t come with these header pins — you
must purchase them separately.
Likewise, a male header pin is soldered to pins D6
and D7 on the Wave Shield (only pin 6 is used here; pin 7
is for future expansion, plus it’s easier to solder on two
pins than just one!). Pin 6 is used to control the LED eyes
and was used as it supports the hardware pulse width
modulation (PWM) capability of the Arduino. By using this
feature, the eye LEDs can be made to rapidly change
brightness, giving them a “flickering” effect.
R = (Vin - Vdrop) / A
where Vin is the voltage applied to the LED (in the
case of the Arduino Uno, it’s 5V); Vdrop is the
forward voltage through the LED; and A is the
desired current pulled from the pin, in amps.
For example, to limit total current for the two
LEDs at 30 mA ( 15 mA per LED) and using the
specifications for the UV LED I used, the
■ FIGURE 5. Twin LEDs serve as flickering eyes.
Small holes are poked into the shirt, and the LEDs
pushed through. Use some Dritz Fray Check to keep
the holes from enlarging over time.