ECE 110/120 Honors Lab Section : Smart Music Player

Gauri Konanoor - gmk2 ECE120

Marshall Shriner - shriner3 ECE120

Tulika Gupta - tulikag2 ECE120

Final Report:

Introduction

Statement of Purpose:

Oftentimes, at parties or in restaurants, people find themselves shouting at one another rather than having a relaxed conversation, because of loud music. We propose designing a prototype of a speaker that measures the volume of the general atmosphere, and increases or decreases the volume of the music depending on that.

Background Research

Certain sound level ranges (we estimate between 40-50 dB) of background music are optimal during an event. If the music is too quiet with respect to the ambient room volume, the event may seem dull or empty. On the other hand, if the music overpowers the room, it is very distracting, annoying, and a detriment to the gathering.

When the music reaches levels of over 100dB, many guests leave with tinnitus that persists for over 30 minutes, some even with permanent ear damage.

Normal conversations occur at 50-60 dB. At a noisy restaurant, decibel levels can escalate upto 70dB. A change in 10 dB doubles the sound.

Design Details

Block Diagram

System

The microphone detects sound and the VU circuit detects volume. The arduino will use that reading to set the music output volume. The arduino will have a limited amount of songs stored on the memory, which we will get from a computer's music library. The speaker will play our stored music. We plan on having two settings for our arduino program: one for background music and one for party music. For background music, we will adjust the volume inversely proportional to the detected room volume, and in the party setting our output volume will be directly proportional to the room volume.

Parts

(Preliminary):

arduino
speaker
Volume Detector
- Condenser microphone
- 6 Volts of power (either from 4 'AA' batteries or a DC power supply)
- 2KΩ-6KΩ resistor (depending on the microphone in use)
- 10Ω resistor
- 10KΩ potentiometer
- 2 10μF electrolytic capacitor
- 100μF electrolytic capacitor
- 0.1μF ceramic capacitor
- 47nF ceramic capacitor
Voltage-Dependent Current Amplifier
- LM386 IC

Possible Challenges

Lack of experience in Arduino programming
Limited Arduino memory might not allow us to store a whole lot of music
Microphone readings may not be optimal
Designing and integrating logic circuits in our project
Microphone taking speaker music as input

Weekly Update Log

10/24: We finished our sound detection circuit and spent most of the hour implementing and messing with our arduino code, while observing the effect each of our changes had on the sensor. We still are having trouble figuring out how to reliably utilize what our microphone is giving us. The remainder of our project will be debugging and fleshing out our code to do everything we want it to do (as of right now we have a shell of the goal), as well as implementing our output logic and amplification circuit.

10/31: We developed a solid idea of our execution of the arduino-controlled volume adjuster. We will use a special transistor to manipulate the strength of an audio signal passing from a computer playlist to the speaker. We plan on attending extra sessions to accelerate the progress on our project.

11/7: We improved the functionality of our sound detection circuit (one of our input pins must not be as responsive as others). We also made progress on the code, making significant steps towards a testable prototype. On the other hand, we have no idea if our prototype test will work at all at this point.

11/14: We presented our progress so far on our project, and also ordered the final part that will hopefully bring our whole project together. We spent most of the time before demo researching further to give ourselves a good idea that this part will accomplish what we want it to.

11/28: We continued planning our code and how to use the digital potentiometer

12/5: We received some more much-appreciated guidance from Alonzo, and succeeded in getting the arduino circuit to change the volume of the music. All we need to do now is test and see if we can change the volume during the song too, instead of just after every song