Your robotic problems solved here.
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emitting a continuous LOUD high pitch beep on 5 VDC,
sounding much like a smoke alarm. (Hams: Here’s the
simplest Morse code practice oscillator circuit ever!)
The beeper draws under 20 mA when powered directly
by a 5V Stamp or PICAXE pin; this is right at the limit, but
fine for intermittent use. I just saw a 3.3V version (eBay
#122396557078), but I haven’t tried those yet; they may
draw higher current. (Note that there are lookalike mini
PASSIVE buzzers on eBay which do not self-oscillate.)
These active beepers are so small, cheap, and useful
that I never build a board without one. It’s usually the first
part I solder onto a new board since it’s nice to hear a beep
or two on powerup. From my experience, this is more
useful for output than an LED status indicator. Also, they
make an occasional beep to remind you if you left the
Again, simply apply 5 VDC using HIGH or LOW to
generate sound, then move on in your program. I prefer to
connect mine active LOW since most MCU pins can sink
more current than they can source. Better safe than sorry!
These can be toggled within your program to give a cricketlike status sound to indicate how fast a loop is occurring.
In this video, the line follower toggles the beeper each
time the laser sensor is sampled: https://www.you
tube.com/watch?v=Q5tBp2_Ya0Y. If desired, more
complex sounds can be generated by sending simple
SOUND or FREQOUT commands to the beeper. Check out
https://www. youtube.com/watch?v=ggah 9mkvx-U
and https://www.you tube.com/watch?v=WBJq
Regarding speech, there are some
old-school voice synthesis chips which
really sound robotic. I wrote about the
then-new RoboVoice chip in my very
first SERVO article in November 2012.
It’s a modern 3.3V dsPIC version of
the 1980’s SP0256 speech chip. It’s
VERY robotic sounding with built-in
text-to-speech algorithms; it also has a
few sound effects built in. You can
see some of my RoboVoice demos at
watch?v= vcu YXErG4Qs.
The speech is good but not
perfect, and regularly needs some
“funneee sspehleeng” to pronounce
some words properly, but that’s all
part of the fun. Download the SP0256
emulator for PCs from www.speech
?itemid= 13 to hear the sounds
generated. Ken Lemieux owns and runs Speechships.com.
He’s currently not making RoboVoice chips, but if enough
people ping his website, maybe we can pull him back in.
His chip is much simpler to wire up than the original 1980’s
Speaking of which, I’ve noticed a glut of cheap SP0256
voice chips popping up from eBay China; #201862134717
is one — under $3 shipped! Tempting, but its authenticity is
uncertain, and it can be a scavenger hunt to round up the
oddball 3. 12 MHz crystal and companion CTS256 text-to-speech chip. RadioShack sold authentic parts long ago
which can also be found on eBay; look for a large GI
(General Instruments) logo on the chip.
Be prepared for LOTS of wiring with these 28-pin chips.
Truly a labor of love and rite of passage for the purists
among us. I have a drawerful of these vintage parts for a
“someday” build. If I ever get a snow day here in Los
Another pinnacle of 1980’s speech technology was the
Votrax SC-01. This chip is currently much harder to find
than an SP0256. Votrax chips were used in arcade games
and various computer products, including Heathkit’s Hero 1
and Jr. robots. Speech quality is better than the SP0256;
there’s a demo at https://www.youtube.com/watch?
v=H7GLSQ-ZRts you can check out.
You can find more info on various speech chips at
www.redcedar.com/sc01.htm, and there’s an online
Votrax emulator at http://real-votrax.no-ip.org.
The “Cadillac” of modern speech modules is the EMIC-
2, which generates amazing sounding speech. It costs ~$60
SERVO 10.2017 9
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