Student Projects
Introduction:
The Idea behind the "myPOD" came from a second year labs project in University, where we were tasked with creating a stereo audio amplifier. I have used the National Instruments myDAQ as a means to read in an audio signal from a standard mp3 player, using LabVIEW I have built a software graphic equaliser and finally output the signal through a transistor power amplifier designed in Multisim.
The equaliser will have three filters with a software signal amplifier on each, these filters will be distributed between 20 HZ and 20K Hz(human audio range). The synthesiser will allow the user to modulate or attenuate any of the chosen filtered signals and also will allow for tracksampling and signal super-imposing.
The power amplifier will consist of two push pull amplifiersof AB class, which will allow for maximum amplification with minimum signalphase shift or distortion. They will be drawing their supply for a single 9V battery which should provide approximately a 4.5V Peak output.
Video Demonstration:
Coming soon!!
Materials:
| Component | Quantity |
|---|---|
| myDAQ | 1 |
| 2N3904 NPN Transistor | 4 |
| 2N3906 PNP Transistor | 2 |
| 3.3 Ω Resistor | 4 |
| 5.6K Ω Resistor | 2 |
| 1.5K Ω Resistor | 2 |
| 18K Ω Resistor | 2 |
| 2.3K Ω Resistor | 2 |
| 1N4001 Diode | 4 |
| 47uF Capacitor | 2 |
| 100uF Capacitor | 2 |
| 8 Ω Speaker | 2 |
| 9V Battery | 1 |
| 3.5 mm Audio Jack | 1 |
Software:
Graphical User Interface:
Simple UserInterface that allows the user to adjust the volume and amplify and attenuatethe Bass, Middle and Treble. Using a power spectrum graph the user can see the frequency ranges of the audio signal and how adjusting the amplification of thefrequency components affects the signal.
Code:
I used the Producer Consumer design template to ensure efficient use of resources such as CPUand RAM, this is particularly important when developing code on laptops orolder computers. Using Express VI’s I have acquired the audio input, filtered the signals into three frequency bands, performed a spectral analysis on the audio signals and outputted the final waveforms.
Hardware:
Using Multisim I have designed and simulated a transistor power amplifier. The software enabled me to rapidly develop the circuit and gauge an idea of the expected output. This significantly reduced the development time.
Finished Product:
Video Tutorial:
Attached Files:
I have created a laboratory project for second year university students to follow.
The code written in LabVIEW 2010.
This was developed by Andrew George NIUK AE Intern 10/11
