September 1999, Issue 110

Taking Orders:
A Speech Recognition Module

INTERFACING CIRCUIT

Depending on the application, you can design various interfacing circuits as well as a generic circuit. Because the output lines (OUT1–OUT8) only remain high for 1 s, some type of latching circuit is needed. For mine, I used one half of a 4013 dual D flip-flop.

The flip-flop, shown in Figure 3, turns the transistor on and off each time a command is given (e.g., if you connect the OUT1 [JP2–12] from the module to pin 3 of the flip-flop).

Figure 3—The 4013 flip-flop latch helps control multiple appliances connected to the VoiceDirect module for speech recognition.

The first time the command associated with word one is given, the flip-flop turns on the TIP120 transistor that lights the LED. The LED remains lit until the command associated with word one is given a second time, turning off the transistor. This way, the same word can turn appliances on and off, and other commands given won’t affect existing commands.

KEEP TALKING

The VoiceDirect module provides a good introduction to the world of speech recognition. It’s easy to implement, easy to train, easy to use—what else is there to say?

John Iovine is the research director at Images Co. You may reach him at john@imagesco.com.