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Published January 25, 2019

Lane of Things 2018 - Sound

Sound sensor construction for the Lane of Things project at Wrigley Field.

AdvancedFull instructions provided857

Things used in this project

Hardware components

Particle Photon

Particle Electron

DFRobot Gravity: Analog Sound Level Meter

Software apps and online services

Google Sheets

Particle Web IDE

Hand tools and fabrication machines

Laser cutter (generic)

X-Carve

Story

Physical Computing Lab

Sound Sensor

The first step was to figure out how to let the microphone on the sound sensor hear sounds without letting water touch it or the board. We came up with a few ideas, including encasing the whole sensor in tape, foam, or a mesh that wouldn't let in water. We eventually settled on removing the microphone from the board and soldering it to a wire, and then soldering that wire to the board. That way, we wouldn't have to worry as much about the board getting wet and only had to worry about protecting the microphone. We created a custom breakout board for the Photon to make it easier to connect the sensor to the correct pins on the Photon/Electron.

1 / 3 • Sound Sensor board

Photon/Electron Code

Next was to write the code. All we had to do was write the code to pull the data from the Photons and Electrons and put it into a Google Sheets. We had to find out how to pull published data from the Particle Cloud and format it correctly into Sheets.

Testing

To test the sensor, we placed it in a box with the microphone muffled by a sweater to prevent any outside noises from getting in. We placed a phone playing white noise in the box with the microphone so we could get control data.

Innovation Creation Lab

Stage 1 - Questioning, Research, and Scouting

Questions/Research

Ways to make the nodes weatherproof
Prevent water from coming in contact with electronics
Limit the humidity/condensation inside of device
Which materials and machines are best to use
Practical ways to attach sensors to walls, poles, etc.
Which microphone to use
How to reduce the amount of echo within the enclosure
Possible ways to remove the microphone from the breadboard
What should be the size of the final design
How would the electronics fit into the design
Best weatherproof mesh to use

All would determine the overall shape of the sensor enclosure.

Scouting of possible attachment sites

Visited the rooftop balcony of the Cubs’ office building
Provided a sense of location and ideas for distributing the sensors around the area
Took pictures of possible deployment areas
Various parking lots around Wrigley
Green and Brown lots

1 / 2 • Pictures of possible attachment sites

Stage 2 - Sketching and Tinkercad Models

Sketching

Putting ideas on paper based on the categories and questions developed in the previous stage. The Sketches

Drawing to scale and labelling components
Accounting for weather conditions and outside factors to protect sensor
Not going into specific details of how they are put together (screws and attachments) but working with the concepts and shapes that would work well
Thinking about materials, space for electronics, and other unique features depending on what was being measured
All the sketches are laid out for the group to look at them so the designs can be refined
With new information, sketches become 3D models in Tinkercad

1 / 3 • Sketchs

Tinkercad Models

Tinkercad is a program used to create 3D models for use in 3D printing
However we used the program in order to visualize and edit our original ideas shown in the sketches
Given two weeks of editing with a checkpoint after one week
Never intended to be the final product, but a way to find good designs that might not have stood out in sketching
Having 3D designs makes it easier to build off of the template when moving into physical prototyping
More consideration given to how the node would be put together and affixed to surfaces

1 / 3 • Tinkercad prototype model

Stage 3 - Physical Prototyping

Design Requirements

Examples of the node types and certain things (perforated walls, etc.) which can benefit the electronics inside
The node should be able to attach to different locations: poles and I-beams
The node should be durable in different weather conditions

Materials Used. Inexpensive lo-fi prototyping - Using inexpensive materials to create replicas of the finished node

Cardboard
Hot Glue
Exacto Knife
Tape
String
Ruler
Pens

Process

Cut the cardboard into desired shapes
Glue cardboard together
Keep in mind the required aspects of the node type (wire placement, water direction, etc.)
Presentation
Shared thoughts on prototypes with class
Explained the advantages + discussed the disadvantages of each potential node
Discuss alternatives to certain design choices and prep for the next phase
Talking Points
This is a mid step between conceptualization and creation of the actual node
Prototyping is important because it allows you to envision what you want to create without spending too much money.
Use of the right measurements is key as it gives a clear visualization of what the node will look like

1 / 5 • Prototypes

The 3D models that came from prototypes

1 / 2 • Final Models

Stage 4 - Build and Deploy

Parts

1. 3 Plates

Carve out the pieces

The 3 plates

2. Acrylic front

Laser cut piece
Bend piece to appropriate shape

3. Rubber gasket

Cut to appropriate size of the acrylic

4. Bottom netting

Cut to appropriate length and size of bottom half of the node

Assembly:

1) Use mallet to knock T-nuts into the bottom of the middle plate. It has a hole in the center and 4 holes in the corners that don't go all the way through the material. The t-nuts go in these 4 holes.
2) Countersink the 4 holes in the corner of the bottom plate (has 4 holes in the corners that go through the material completely). We don't have a countersink bit that matches the angle of the machine screws so use a slightly larger one and be careful not to go all the way through the material.
3) Clamp the middle plate (with the t-nuts mounted) to the backplate (with channels and "ear") and use the guide holes in the bottom of the middle plate to pilot two holes into the side of the backplate. Flip the backplate around and do the same on the other edge. Use panhead screws to attach these two plates together with a strip of foam between them. Trim excess foam.
4) Use a drill bit to expand the size of the hole in the center of the middle plate. Microphone board goes here with mic facing downwards.
5) Use belt sander to modify the edges of the c-shaped acrylic pieces to fit into the assembly tightly with gaskets. Drill a hole in the front center of the middle plate and top plate for a 10-32 screw at the front edge of the gaskets of the top and bottom of the c-section at the front.
6) Assemble baseplate and middle plate by using 4 2" screws through the bottom plate, with long spacers, into the t-nuts.
7) Mount sound boards into top plate using 4-40 screws and spacers. Should be centered left-right and towards the backplate (at least.75" away from the back edge of the top plate). The c-sections are not all the same size/depth so make sure it fits per device.
8) Hot glue the microphone board in place in the middle plate, inside the box. Then place the antenna diagonally in place above it within the c-section place. Finally seat the top plate and attach it with 2 pan head screws. Use foam strips between the backplate and top plate and trim excess.
9) Pass the long 3" screw through the two holes you drilled previously in the top and middle plates and fasten with a bolt, tightening to compress the gaskets on the top and bottom of the c-section.
10) Wrap the spacers between the bottom and middle plate with double-sided tape. Wrap the hdpe mesh around the spacers, starting and ending with a little extra at one corner. Use wire to loop around the spacer where they meet and tighten to hold fabric in place.

1 / 3 • Final Products

Schematics

Code

#define SoundSensorPin A1  //this pin read the analog voltage from the sound level meter
#define VREF  3.3  //voltage on AREF pin,default:operating voltage
double voltageValue,dbValue;

double count;

long avg_accum = 0;
double dbMin = 100;
double dbMax = -1;
double dbAvg = 0;


// measure volage, return dB
double dBA()
{
    voltageValue = analogRead(SoundSensorPin) / 4096.0 * VREF;
    return dbValue = voltageValue * 50.0;  //convert voltage to decibel value
}    

double minuteReading() {
    double avg = avg_accum/count;
    digitalWrite(7, HIGH); // just a little blinky so we know things are working
    return avg;
}

void resetValues() {
    avg_accum = 0;
    count = 0;
    dbMin = 100;
    dbMax = -1;
    digitalWrite(7, LOW);
}


void setup()
{
    pinMode(7, OUTPUT);
        
    Particle.variable("min",dbMin);
    Particle.variable("max",dbMax);
    Particle.variable("avg",dbAvg);
    
    Time.local();
}


void loop()
{  
    double dB = dBA(); //Serial.println(dB);
    Serial.println(dB);
    avg_accum += dB; // accumulate values for average
    count++;         // accumulate count for avg    
    
    if(dB > dbMax) { dbMax = dB; } // get max
    if(dB < dbMin) { dbMin = dB; } // get min
    
    if(Time.second() == 59) {

       dbAvg = minuteReading();
       resetValues(); // reset values for the next minute count
  }
}

var sheet;
var accessToken = [Your Particle Access Token];


function getSoundLevel() {
  try
  {  
    sheet = SpreadsheetApp.getActiveSheet();
    
    
    var deviceObject = UrlFetchApp.fetch("https://api.spark.io/v1/devices?access_token="+accessToken);
    deviceObject = JSON.parse(deviceObject.getContentText());
    
    for (var i =0; i < deviceObject.length;i++){
        addRowFromDevice(deviceObject[i]);
    }
    
   
  } catch (e)
  {	
	Logger.log(e.name + ": " + e.message);
	throw (e);
  }
}

function addRowFromDevice(device){
  var min = 0; 
  var max = 0;
  var avg = 0;
  var status = 0;
  var connected = (device.connected==true);
  
  try{
    if(device.connected!=false){  
      var response = UrlFetchApp.fetch("https://api.spark.io/v1/devices/" + device.id + "/max?access_token=" + accessToken);
      var jsonResponse = JSON.parse(response.getContentText());
      max = jsonResponse.result;
      var response = UrlFetchApp.fetch("https://api.spark.io/v1/devices/" + device.id + "/min?access_token=" + accessToken);
      var jsonResponse = JSON.parse(response.getContentText());
      min = jsonResponse.result;
      var response = UrlFetchApp.fetch("https://api.spark.io/v1/devices/" + device.id + "/avg?access_token=" + accessToken);
      var jsonResponse = JSON.parse(response.getContentText());
      avg = jsonResponse.result;
    }
  }catch(e){
   connected = false; 
    
  }
    var timeStamp = new Date();

  sheet.appendRow([timeStamp, min, max ,avg, device.id, ((!connected)?"Not ":"")+ "Connected",device.name]);
  
}