LabVIEW Voice Recognition Project [Senior Project Lab Report]

3.1 Project Building Blocks

The following diagram is the flowchart that is used in this project.

Figure 6: Project Flowchart

There are a total of six blocks for the LabVIEW Voice Recognition project. The first block is the input device, which is the microphone. The input data from the microphone gets sent to the sound card in the PC. The input data acquisition function on the main block diagram collects the sound data in the PC. While the code is executing in LabVIEW, the third block in the chart and the Software block, the system compares the spoken command to the stored commands in one of the VIs. If the command is recognized, then the NI 9403 sends a digital output to the LEDs.

The following components used in this project are:

· 5 LEDs

· 5 330-ohm resistors

· NI 9403 Module

· PC

· Desktop Microphone

3.2 Block 1: Input Device

The first block in Figure 6 is the input device, which is the microphone. Originally, a USB microphone, a digital device, was going to be used for the project. However, it was implied that LabVIEW may have difficulty detecting signals. Thus, an analog desktop microphone was used.

What is the difference between analog and digital devices? Kate T. Poonam, writer of the article "Analog vs Digital", states that "The difference between analog and digital technologies is that in analog technology, information is translated into electric pulses of varying amplitude. In digital technology, translation of information is into binary format (zero or one) where each bit is representative of two distinct amplitudes." Poonam lists additional details regarding the differences bet ween analog and digital. For instance, when it comes to signal types, analog signals are continuous while digital signals are discrete. Doug Lowe, author of "The Difference Between Analog and Digital Electronics", also distinguishes between the two circuits. He states that "Analog refers to circuits in which quantities such as voltage or current vary at a continuous rate" and that "In digital electronics, quantities are counted rather than measured."

The only type of digital microphone is the USB microphone, as microphones are typically analog devices. Arthur Fox, who wrote "Are Microphones Analog or Digital Devices?", states that the difference between an analog and digital microphone is based on the output type. As the names imply, analog microphones produce analog outputs while digital microphones produce digital outputs. Each microphone type contains their own set of advantages. For instance, digital microphones are easy to use and the analog-to-digital conversion that takes place in the USB reduces electromagnetic interference. However, digital microphones are limited to one microphone at a time. On the other hand, analog microphones allow wider variety. The article states that the only disadvantage of analog microphones are situations where an audio interface or analog-to-digital converter is needed.