Sunday, March 10, 2013

Testing the EMIC 2 Speech Module

The EMIC 2 speech processing module allows any Maker to add spoken word capability to a project.  The board is designed by Grand Idea Studio and marketed by Parallax, having been released last July.  It is carried by Maker Shed, Adafruit, and most recently Sparkfun.
I wanted to make the simplest connection between a Windows laptop to the module.  My setup consists of an iteadstudio.com Foca 2.1 board to convert the PC USB connection to a TTL level serial connection.  Other USB to serial options would be a 3.3 volt or 5 volt FTDI Friend cable or other USB to serial boards on the market.  I like the Foca as it is also a USB to Xbee adapter and works at dual voltages (and only costs $7.50 compared to $20 for the single use, single voltage FTDI friend.
The Foca is set for 5 volts but the EMIC 2 module works at 3.3 volt signal levels also
If your USB to serial connection cannot provide at least 220 milliamps then you will need an external power supply to power the EMIC.  The typical USB port can supply 500 milliamps.  The Foca current rating is not published but worked well in testing. 

The connections are made via a female to female multiconductor cable (a couple of dollars on Ebay, also at Adafruit).  Connect the 5 volts and ground from the serial connection to the EMIC board.  The transmit pin on the serial board goes to the receive pin (SIN) on the EMIC.  Likewise the serial receive pin connects to the EMIC data output (SOUT) pin.  
EMIC 2 connections: Ground, 5 volts, SOUT, SIN, and speaker pins.  The white cable is the audio output.
Sound output can be via an 8 ohm speaker from the two remaining EMIC 2 pins or via the mini jack.  I connected the EMIC board via a mini plug cable (white) to an amplified speaker I had in the shop (an antique Radio Shack amplified speaker).  Headphones or another type of amplifier would work also.

Double check your connections (twice).  Plug the USB cable into the PC and the EMIC board LEDs should light, first colors then green if ready.  If you do not have lights, unplug and check your connections. 

You may then talk to the EMIC module via a PC terminal program.  PuTTY is free and configurable.  Use your favorite.  Set the communication to 9600 baud, 8 bits, 1 stop bit, no parity.  It would help to set local echo and Carriage Return is Line Feed and visa versa to make display easier for you.
A PuTTY terminal on the left, the EMIC 2 data sheet on the right for commands.
The commands to have the unit talk are in the datasheet.  The nest test is to type D0 (the letter D then the number zero).  The EMIC will then run through its test dialog in English.  D2 will speak in Spanish.  If you wish to speak a sentence, preface it by the letter S.  You can change the voice using the command N followed by a number from 0 to 7.  All have a mechanical sound but are quite good.

Youtube video of the project:



This is a fun module - it takes me back to the speech heyday where the home had a speak-n-spell and the work computer had a DECtalk box.  The EMIC 2 actually will emulate a DECtalk and that command set allows for fine control of the voice process.  The DECtalk box came out in 1984 at a price of $4,000.  The EMIC 2 is available for about $59.99 (less with 10% off sales, Saturday nights on Adafruit, randomly at Maker Shed).

Next: Incorporate the EMIC into projects - I had thought of adding it to my robotic head projects but I would like a talking alarm system more.

I have  a vintage speech system I made in 1985.  I'll blog on that soon.

PS Sorry for the pink background, I had previously fixed an older Dell laptop and it made a handy platform.