ADVENTURES IN PROPELLER PROGRAMMING
■ BY JON WILLIAMS
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Those that know me well know that this is my favorite time of year. Halloween
is right around the corner and that's followed up by the Christmas "season"
— a couple months where prop displays flourish and indoor/outdoor decorators
feverishly work to eclipse their creations of years past. I love this season. A lot
of my electronics work involves small-scale show control and now — thanks to
my favorite show control software — things are even better.
About five years ago, I came across a neat piece of reeware called Vixen that was created by a really
nice guy named K.C. Oaks. The original intent behind
Vixen was to allow DIY Christmas lighting enthusiasts to
have a free platform on which to create complex shows.
While playing with Vixen, it dawned on me — as it would
any hacker worth his/her salt — that if I could control lights
with Vixen I could control just about anything else; it’s a
matter of thinking in terms of channel level(s) meaning
something other than light intensity.
In addition to being an outright nice guy, K.C. is
amazingly responsive to customer requests for new
features and software modules used by Vixen. To his
credit, the program design is highly modular which allows
him (and others with .NET programming skills) to make
additions without upsetting the entire apple cart.
I recently asked K.C. for a new add-in module that will
export the show data to a file in binary format. This keeps
the files as small as possible. By adding a microSD socket
and the FSRW object to a Propeller project, we can play
that file without the need for a computer. This is big! We
can use Vixen to create complex sequences, save them to
a file, and then have the Propeller chip play them back.
As I mentioned earlier, I do a lot of small-scale show
control programming. There are times when programming
complex sequences in code can become extremely
tedious. Developing a sequence in Vixen that can play
through our hardware while we’re developing is important
— so we’ll start there. The second step will be to create a
program which can open and read a file exported by
Vixen — completely untethered from the PC. We get the
best of both worlds: Use a graphical interface to “paint”
our sequences and play them live;
once satisfied, export them and play
them right off an SD card.
■ FIGURE 1.
You’ll need to pop over to
www.vixenlights.com to download
the latest version of Vixen. You’ll
want to download the driver
updates K.C. has provided for me at
the article link (you can also find
these in the Vixen section of the
EFX-TEK support forums).
Just a note on replacing DLLs
used by Vixen: If you don’t want to
overwrite a DLL used by Vixen, you
can rename it but you must rename
the extension. This is important! All