Basic Votrax SC01 Speech Synthesizer library for Arduino

I’ve got a few old 80′s voice synths lying around, and from time to time pull them out to play with them. Most recently I decided to make a basic shield on protoboard to interface one to an Arduino; I also decided to forward-port some of my code to make an easier way to work with them.

This library isn’t my prettiest work, but it’s pretty easy for basic use. Generally you only need to make an instance of the VotraxSC01 class, and call the “say” method on a string containing the names of the phonemes you want to pronounce, e.g.

#include “VotraxSC01.h”

VotraxSC01 sc01;
…
sc01.say(“H EH1 L O”); // say “Hello”

There are some other “say” methods for using phoneme values directly, and a VotraxSC01Phoneme namespace with constants naming all the phonemes for easy reference. Generally if you’re just playing around you really won’t need this stuff; it’s mainly useful for packing a lot more phrases into the Arduino’s memory, and I’d suggest sticking with the string version unless you’re actually doing something that uses a lot of memory.

You can look at the data sheet for the phoneme names to use, or look at the VotraxSC01.h file and look at the VotraxSC01Phoneme names; the phoneme names to use in strings match the names there.

To use the library, unpack the tgz in your Arduino software’s hardware/libraries directory; it will create a directory called VotraxSC01. You can then use the library like above. There also is a file in the directory called CONNECTIONS that has a basic rundown of what you need to hook up for the library to work. The library expects the chip to be connected to digital pins 2-11 (taking up most of your IO; it would be possible to use a shift register to decrease the necessary lines, but the library would need to be modified accordingly). This isn’t the easiest chip to get working, as it requires a 7-14 volt supply, some connections for an RC oscillator circuit, and an optional external amplifier… but it’s not as hard as some other chips I’ve worked with.

You can download the library here.