by Jon Williams
Putting the Spotlight on BASIC Stamp Projects, Hints, and Tips
Speak the Speech
Add some eloquence to your next
project — give the gift of gab!
Speak the speech, I pray you ...” starts Shakespeare’s
famous instruction to the actor. The essence of this
admonition is for the actor to speak truthfully and
easily, without fabrication or extended effort. This is
important to me because, as many of you know, I lead
two lives: one as a happy-go-lucky Parallax employee, the
other as a professional actor. What does this have to do
with BASIC Stamps? Have faith, friend, this is my cheesy
introductory text and you know I’ll get there!
Almost all actors go through a stage where nothing
that comes out of their mouths sounds right. Believe it or
not, it takes a lot of work to sound completely natural while
speaking words written by someone else — especially in
the surreal atmosphere of a stage or film set. The
challenge is elevated for the film and television actor, since
conversations are rarely shot in a single continuous take.
So, where am I going with this? Just as the actor
struggles, frequently we techno-types struggle when
adding speech to our electronic projects. Sure, there are
lots of neat products out there, but most (allophone
based) are more difficult to use than the quality of their
output warrants. It may take an hour to string together the
right collection of allophones to get decent speech and,
still, it usually sounds very unnatural. Yes, we ultimately
get there, but, man, is it a struggle.
Enter Winbond. The company responsible for the
ChipCorder® products has created a true text-to-speech
product — called the WTS701 — which makes converting
plain English text into high-quality spoken speech fairly
straightforward. Okay, fairly straightforward is a relative
term — and the WTS701 itself is a bit tricky. The device
contains a rules processor for handling English text and a
memory that consists of actual speech fragments that —
when strung together properly — produce surprisingly
pleasing, female speech. To my ear, the voice sounds a bit
like that of “Mother” from the movie, Alien.
The Emic TTS
Figure 1. The Emic T TS (SIP version).
NUTS & VOLTS
If you happen to go to the Winbond site ( www.isd.com)
and get the datasheet for the WTS701, you’ll probably say,
“Uh, oh ...,” out loud. Don’t worry. A Southern California
company called Grand Idea Studio has created a product
called the Emic Text-To-Speech Platform (Emic TTS) that
shields us from the complexities of the WTS701, yet gives
us access to its impressive features.
The Emic TTS comes in two flavors: an OEM version
and prototyping-friendly SIP version. We’re going to be
using the SIP version here because it will plug right into a
solderless breadboard and it includes an onboard
300 mW amplifier — all we have to do is connect an 8 Ω
speaker. The SIP version also allows us to route external
audio (i.e., Stamp-generated sound effects) through the
WTS701 and to the audio amplifier. Another nice feature
of the SIP version is that is has the same pin-out as the
Quadravox QV306 modules. So, if you have a project that
is using the QV306 with prerecorded speech, you can swap
in the Emic TTS and update your code for direct text-to-speech output. There are advantages to both modules and
I like the ability to move back and forth between them.
Just Say It, Please ...
What makes the Emic TTS so much fun to use is that
it’s just plain easy to make a project talk. For example:
SEROUT Tx, Baud, [Say, “Nuts & Volts rocks!”, EOM]