LabVIEW Voice Recognition Project [Senior Project Lab Report]

Chapter 3.0 System Design

3.2.1 Implementation and Testing

The microphone was tested using the VIs that were created at the initial development of the project, discussed in Section 2.2. How the volume affected the output waveforms, and the output numeric indicators were observed. Once the volume of the input data successfully activated the LEDs using digital outputs, based on the program's conditional statement, it was an indicator that it was ready to be used in Rahul's code.

3.3 Block 2: Conversion Device

The conversion device in this project was the desktop, or PC, itself. The PC offers a analog to digital conversion in a way that the computer is able to read. Fox, who also wrote "How to Connect a Microphone to a Computer (a Detailed Guide), explains that the conversion occurs in the audio interface. He states that an audio interface is a device that allows communication between computers and mics, instruments, loudspeakers, and monitors." He goes on to explain that audio interfaces are "...improved external sound cards for your computer." Having a successful conversion from analog to digital audio signals will enable necessary signals to be captured in LabVIEW.

3.3.1 Implementation and Testing

As the microphone and PC directly communicate with one another, testing for successful analog-to-digital conversions were performed using the sound VIs discussed in Section 2.2.

3.4 Block 3: Software

The software used was the 2020 National Instruments LabVIEW. As stated previously, LabVIEW is a graphical coding platform. 

3.4.1 Program Explanation

LabVIEW will collect the data using the Acquire Sound Express VI, as shown in Figure 7. LabVIEW stores sound data as an array of waveforms and each waveform is correlated with a singular channel.

Further details on Rahul's code will be discussed in later sections. But essentially, a command is spoken into the microphone. After the input is received, the data gets compared to the data in the matrices stores in one of the sub–VIs. If that command is successfully recognized, then the front panel indicators are activated, and a digital output is sent to the LEDs.

Figure 7: Acquire Sound Express VI

3.4.2 Implementation and Testing

Most of the focus in this project was on the software. The components within the VIs had to be configured as the whole program is speaker dependent. Multiple steps, which will be explained in later sections, were applied to make the system work.

3.5 Block 4: Output Module

The output module that was used was the National Instruments (NI) 9403 Module. It is a configurable digital input and output interface.

3.5.1 Module Display

Figure 8: NI 9403

3.5.2 Implementation and Testing

This device is what enables the digital outputs. Just like with the microphone and PC, testing occurred in the created sound VIs.

3.6 Block 5: Hardware Circuit

To enable a single digital output, the following components are required: A resistor and a 5 mm LED.

3.6.1 Schematic

Figure 9: Breadboard Schematic

3.6.2 Implementation and Testing

In the schematic shown in Figure 9, the positive end of the LED is wired to one of the DIO ports while the negative end is connected to the 330-ohm resistor, which is wired to ground. Just like the other blocks in the flow chart, they were tested in the created sound VIs. In addition, this schematic was repeated five times for each command in the program.