it has its own five volt regulator. I went with an external
supply so that I could safely light all 24 WS2812s, and
even connect to a second ring if I desire. Yes, it's okay to
connect an external 5V supply to the 5V pin on the Mini;
just make sure that you leave the VIN pin floating.
I used a rotary tool to cut a piece of perfboard to fit
inside the LED ring. Remember to wear a dust mask when
doing this; fiberglass dust is not good for the lungs. After
adding male pins (they're provided) to the Mini, I pushed
the female sockets onto those pins and then centered the
assembly in the perfboard. The connections are easy: 5V
to the Mini and LED ring; and one pin from the Mini to
the DIN pin on the ring through a 330 ohm resistor.
Figure 5 shows all the components soldered and ready for
installation.
I mounted the Propeller Mini and LED ring to a piece
of scrap cardboard with double-sided foam tape. To this, I
attached a diffuser element made from a piece of plain
printer paper. We need a diffuser because we don't want
to see direct light from the LEDs; it is the variance in the
indirect light that creates the effect. Don't worry, the
diffuser doesn't have to be fancy (see Figure 6 for proof!),
and it only needs to cover the front half of the LEDs.
Leaving the back half open allows more light to bounce
around inside the Jack-o-lantern.
This was really simple. In a couple hours, I upgraded
my Jack-o-lantern from a few LED wicks to a color-controlled flame effect. My Jack is pretty standard, so the
colors (dark red to bright orange) I chose for the flame
levels are standard as well. Remember, though, this is all
about the art. If you have a cool purple pumpkin, you can
give it some cool purple flames instead.
Finally, your display doesn't have to be as docile as
mine. You could connect a PIR or mat switch to respond
when a trick-or-treater comes near. The construction phase
will take a couple hours. It's the playing with the code
phase where you'll have the real fun and spend the most
time. You've got a bit of time before the big night, so get
to it!
Happy Halloween, and here's to spinning up a lot of
cool creations with the Propeller chip! NV
September 2015 31
FIGURE 6.
