resulting point. Repeat. Repeat. Repeat. Any in-band
energy will have the effect of growing the distance
of the point from (0,0) as it rotates at the resonant
frequency. This is key to making vowel sounds.”
I probably look more than a little confused. He
adds: “You’ve got to excite that resonator. It’s like a
bell. Bing-gggg. That took me forever to figure out
but it was very simple.” I’m not sure I follow everything he says, but I get that here is a guy who works
and works an idea and pushes it forward, bit by bit,
and eventually gets somewhere. He works at a level
of electronics that is completely ethereal to most of
us, but not to him.
“Ultimately, everything has to be physical so we
can perceive it with our senses,” Gracey says. “The
hardware is like the body and the software is like
the spirit. The whole point of the Propeller chip is to
make an able body for the kind of spirits you want
to create. Like speech synthesis.”
Gracey’s immediate goal is to write a state-of-the-art sound synthesis library for the new
Propeller chip. He explains that existing speech
synthesis applications “almost always require a
dedicated speech chip.” By adding sound synthesis as a software capability with the Propeller, he
can make it affordable to create applications that
generate a vocal track. He adds: “The whole point
is to enable inventors to make stuff they couldn’t
make before.”
From the beginning, Parallax has offered an
embedded platform, distinct from the PC and
Windows, for hobbyist and educational projects, not
to mention professional uses. Why not just use a PC?
Gracey says a PC can get expensive for a number
of applications, especially when compared to using
the BASIC Stamp controller. However, he says the
“big sleeper issue is reliability because Windows
seems to blow itself up in time.”
Neither BASIC Stamp nor the Propeller have an
operating system. Why? “The systems are so simple
that the code you write is the operating system.” He
sees the microcontrollers as deterministic systems
that do what you tell them to do; put an operating
system onboard and you will have something with
a mind of its own. PCs are interrupt-driven, which
means the operating system is designed to interrupt what it’s doing if it thinks it should be doing
something else; a PC usually hosts multiple applications. Embedded applications typically are designed
to do one thing — such as read an RFID tag and unlock a door, or monitor and store GPS coordinates
of a rising weather balloon — very well.
The landmark BASIC Stamp controller is a custom circuit based around an 8-bit Microchip PIC chip,
running Parallax’s now famous BASIC interpreter,
plus a high-level development environment. Other
models in the BASIC Stamp family are based on a
Scenix SX processor or may come with more I/O
78 Make: Volume 10
