Group 702 Sound Sensor Project

Our project detects sound and the data is collected so that we can measure at what points in the day has the highest amount of volume.

IntermediateFull instructions provided20 hours578

Things used in this project

Hardware components

Particle Photon

Breadboard (generic)

Jumper wires (generic)

Hand tools and fabrication machines

Laser cutter (generic)

Story

The journey began with a question... "What if we could tell a story through sound?"

This question is interesting because if we could use the sound data collected to somehow show what happened during the time frame of huge spikes in sound, we can make inferences backed with metadata about what really went on that day. We decided to measure the highest level of sound everyday every minute for a week. We felt it was best to put the sensor in a music room because we could use the data to show what certain points in the day had the highest levels of sound.

Building our device was no easy task as there were many ideas that had to go into prototyping and design. We needed a structure that could collect sound efficiently, so initially we went with a pyramid shape but found many complications. There was no way to mount a pyramid on the wall without having it fall or fail to collect efficient data. Then we came up with our design to have a rectangular prism with a open pyramid on top to be able to mount it properly and collect the sound we needed.

The code was developed in a way that would efficiently collect multiple sound readings and convert them into a average amount for that reading. This would occur every minute so for an entire day of school it would collect this data.

Some challenges we discovered were with the design and how to create a device that had a shape that collected data in the most efficient way but also looked professional. Some other challenges we had were with the code that took the data from the device and inputed it into a google spreadsheet.

What we learned from this project was how to come up with a question that was interesting or important and how to develop an idea and turn it into a physical device. From our project we learned about the collection of sound data and how it could be turned into interesting data for us to share with people such music teachers.

This is the sound data.

This is the average sound data.

Final Product (side view)

Final Product(Top view)

Prototype(Side view)

Sketches

Prototype(Tope view)

Sound Code for Photon

const long sample_rate = 50; // time between samples (in miliseconds)
const int array_size = 1200; // 1000/50=20 * 60=1200
int snd_array[array_size] = {};
int snd_max, prev_max = 0;
int snd_min, prev_min = 4096;
double snd_avg = 2048;

const int blink_thresh = 2048;

unsigned long broadcast_interval = 3000;
unsigned long last_broadcast = 0;

void averageReading(int value) {

    // Shift all the values right by 1
    for(int i = array_size-1; i >= 1; i--) 
    {
        snd_array[i] = snd_array[i-1]; 
        if((snd_array[i] < snd_min) && (snd_array[i] != 0))
        {
            snd_min = snd_array[i];
            
        }
        if(snd_array[i] > snd_max)
        {
            snd_max = snd_array[i];
            
        }
    }

    snd_array[0] = value; 

    // Average array
    float avg_sum = 0; 
    int size = 0 ;
    for (int a=0; a <= array_size; a++) 
    {
        if(snd_array[a] > 0)
        {
            size++ ;
            avg_sum  = avg_sum + snd_array[a];
        }
    }
    snd_avg = avg_sum / size;
}

void blinkMic(int reading) {
    if(reading > blink_thresh) {
        digitalWrite(D7, HIGH);
    } else {
        digitalWrite(D7, LOW);
    }
}


void checkBroadcast() {
    unsigned long now = millis();
    if((now - last_broadcast) > broadcast_interval) {
        Serial.print("Avg: "); Serial.println(snd_avg);
        Serial.print("Min: "); Serial.println(snd_min);
        Serial.print("Max: "); Serial.println(snd_max);
        snd_avg = 0;
        snd_min = 4096;
        snd_max = 0;
        //snd_array[array_size] = {};
        last_broadcast = now;
    }
}

void setup() {
    Serial.begin(9600);
    pinMode(A0, INPUT); // mic AUD connected to Analog pin 0
    pinMode(D7, OUTPUT); // flash on-board LED
   
    Particle.variable("snd_avg", snd_avg);
    Particle.variable("snd_max", snd_max);
    Particle.variable("snd_min", snd_min);

}

void loop() {
    int mic_reading = analogRead(0); //Serial.println(mic_reading);
    blinkMic(mic_reading);
    averageReading(mic_reading); 
    checkBroadcast();

    delay(sample_rate);
}