■ FIGURE 11. Finished baking.
■ FIGURE 12. Completed
■ FIGURE 13.
ends randomly placed (with the help of a tester
program). The ends of the fibers are painted black to
look like ash; the bundle is wrapped in cloth tape to
look like a wick. Finally, the ends are cut and trimmed at
random angles. The painting and wrapping was another
great artistic call by my friend, Mike Deak, and it really
sells the effect. By running a random pattern through
the LEDs, the wicks appear lit and sparking.
There is a random operator in the Spin language,
but many have demonstrated that it's not as random as
one would hope. No problem! A forum member
translated a popular C algorithm to Spin and it works
nicely. For those times when I want to get really crazy, I
seed the PRNG (pseudo-random number generator)
object with the RealRandom object — that wasn't
necessary for a simple trade show display. Here's how
simple creating output for the wicks can be:
prng : "jm_prng"
dira[PWM_Y..PWM_R] := %1111
outa[PWM_Y..PWM_R] := prng.random
Uh ... yeah, it's really that easy. Start the PRNG
object, make the LED pins outputs, then write a random
pattern to the LEDs every 25 ms.
Of course, if this was the only thing we had to do,
we could have used far simpler hardware, but those
props also have WS2801 LED strings in them so that the
skull graphic can throb and change colors. There is a
TC4427 and stout 5V power supply on the QuickStart
LED driver board specifically for this task.
Well, that's a wrap. If you're new to the Propeller
and haven't cracked open your QuickStart yet, jump on
it! You're just delaying having fun. If you've thought
about making your own QuickStart shield, well, just do
it. There's a bit of a movement with users creating
custom QuickStart shields; Jeff Ledger (
powered.us) has some nice boards, and Ray Allen
www.rayslogic.com) has some really neat stuff, too.
In fact, next time we're going to jump into Ray's
QMP (Quick Media Player) shield and I'll share my
secret for playing high quality WAV files with the
Until next time, then, keep spinning and winning
with the Propeller! NV