Production Ready Sound Level Monitoring Solution

Milesight WS302 Sound Level Sensor Blueprint Guide

The Milesight WS302 Sound Level Sensor monitors and analyzes sound levels in various environments, providing metrics such as instantaneous sound levels (LA), equivalent continuous sound levels (LAeq), and maximum sound levels (LAmax). It also monitors battery levels and RSSI for reliable operation. This guide provides step-by-step instructions to set up the sensor, register it with The Things Stack (TTS), and integrate it with Blynk IoT for data visualization and control.

Step 1: Unpacking and Initial Setup

1.1 Required Components

• Milesight WS302 Sound Level Sensor
• LoRaWAN Gateway for connectivity

1.2 Initial Setup

1. Verify Package Contents: Make sure all components are included and undamaged.
2. Install the Batteries: Insert the batteries into the sensor, ensuring the correct polarity.
3. Power On the Sensor: Hold the power button for 3 seconds. The LED will confirm activation.

Step 2: Registering the Sensor on The Things Stack (TTS/TTN)

2.1 Setting Up the LoRaWAN Gateway if you don't do this before

1. Log in to the TTN Console: Visit the TTN Console.
2. Add a Gateway:
   • Navigate to Gateways > Add Gateway.
   • Enter:
     • Gateway EUI (found on the gateway label)
     • Gateway ID (e.g., my-lorawan-gateway)
     • Frequency Plan for your region (see the table below)
   • Click Register Gateway.
3. Configure the Gateway:
   • Follow the manufacturer's instructions to connect the gateway to TTS.
   • Ensure the gateway is online and visible in the TTS Console.

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Frequency Plans

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2.2 Creating a New Application

1. Log in to TTS Console.
2. Create an Application:
   • Navigate to Applications > Add Application.
   • Enter:
     • Application ID: A unique name (e.g., sound-monitor).
     • Description: (e.g., Monitoring environmental noise levels).
     • Handler: Select the handler for your region.
   • Click Create Application.

Note: To ensure smooth operation, it’s recommended that all devices within a TTS application are of the same sensor type (e.g., WS302). If you’d like to use different types of sensors, consider creating a separate application for each sensor type. This helps maintain better compatibility and performance.

The dashboard for the created application looks like this:

2.3 Pairing the Sensor with the TTS Application

1. Download and install Milesight ToolBox App
2. Open the Milesight ToolBox App:
   • Pair the sensor via NFC.
   • Navigate to Settings -> LoRaWAN Settings.

3. Configure LoRaWAN Parameters:
   • DevEUI: Use the default value (found on the sensor label).
   • AppEUI: Use the manufacturer’s default value or generate a new one.
   • AppKey: Use the manufacturer’s default or generate a new one.
   • Frequency Plan: Match the frequency plan configured in TTS.
   • RX2 Data Rate: Set to DR3 (SF9, 125 kHz).
   • Spreading Factor: Set to SF10-DR2.
   • Default Application Port: Set to 85.
   • Use the Write button to save these settings via NFC.

2.4 Configuring MQTT Integration in TTS

1. Navigate to TTS Integration Settings:
   • In the TTS Console, open your application and select Integrations.
2. Select MQTT:
   • Click MQTT from the available integration options.
3. You’ll need these details to set up the MQTT integration in Blynk:
   • Server Address
   • Port
   • Username
   • Password: Click Generate new API key and copy the generated key. Keep it secure.

• In the API Keys section of the left menu, select the newly generated key.
• Under Rights, select Grant individual rights and ensure the following permissions are enabled:
  • View device keys in application
  • Create devices in application
  • Edit device keys in application

Step 3: Integrating TTS with Blynk

3.1 Configuring Blynk Integration via MQTT

1. Click "Use Blueprint" at the top of the WS302 blueprint page.
2. Set Up MQTT in Blynk:
   • Navigate to Developer Zone -> Integrations -> The Things Stack -> Add, and choose the template named Milesight WS302.

• Enter the data from Step 2:
  • Hostname: MQTT server address with port 1883 or 8883 (e.g., eu1.cloud.thethings.network:8883)
  • Username
  • Password: The copied API key
• Click Connect.

3. Enable Automated Device Onboarding:
   • Once connected, click Edit and toggle Enable automated device onboarding.
   • Specify the LoRaWAN version, frequency plan, and regional parameter version.
   • Enable "Support class B" and/or "Support class C" if required.
   • Specify The Things Stack component addresses (found under Network Information in the Admin Panel).
   • Save changes.

Step 4: Onboarding the Sensor to Blynk

1. Go to Developer Zone > My Templates > select Milesight WS302, then click Activate Device.

2. In the new window, enter the data provided in Step 2.3:
   • Application Key
   • Join EUI
   • DevEUI

3. Click Next and wait for the device to come online.

You can verify the device’s status in TTS. To add more sensors, create new devices in Blynk following the same process. Once the device is online, you'll be redirected to the dashboard to test your setup.

When data from the sensor is received in TTS, you will see something like this in the dashboard:

Step 5: Monitoring and Analyzing Data

5.1 Dashboard Overview

The dashboard is preconfigured, providing an intuitive interface for real-time monitoring. Both web and mobile dashboards offer the same functionality. Key features include:

• Device Overview:
  • Displays Device Name, Device Owner, and Company Name
  • Shows online/offline status
• Power (V5): Displays the power status (On/Off toggle)
• Battery (V0): Shows the battery percentage
• RSSI (V6): Indicates the received signal strength in dBm
• Time Weighting (V4): Displays the current time weighting configuration
• Instantaneous Sound Level (V1): Shows the current sound level in dB
• Continuous Noise Exposure (V2): Displays the equivalent continuous sound level in dB
• Maximum Recorded Sound Level (V3): Indicates the maximum sound level recorded in dB
• Custom Chart:
  • Time-series visualization for LA, LAeq, and LAmax
  • Selectable time intervals (e.g., 1 hour, 6 hours, 1 day)
• Location Map: Displays the sensor's geographical location

5.2 Settings Overview

• Frequency Weighting (V7): Choose between A and C frequency weightings
• Fast Time Weighting (V8): Toggle fast time weighting On/Off
• Reporting Interval (V9): Set the data reporting interval (Live, 15 sec, 30 sec, 1 min)
• Built-In LED (V10): Toggle the built-in LED On/Off

Step 6: Setting Alerts

1. Log in to Blynk Console.
2. Create Automations:
   • Choose Device State
   • Choose your device and triggers for specific thresholds (e.g., LAeq > 80 dB).
   • Define actions (e.g., send notifications).
3. Save and Test:
   • Simulate events to ensure triggers activate correctly.

Step 7: Adding Location in Blynk

5.1 Configuring Location

1. Go to Location Section in Blynk:
   • In the Blynk dashboard, navigate to the Location section.
2. Add the Address:

• Enter the sensor's address or drag the pin on the map to the correct location.
• Save the location.

3. Assign Location in Metadata:
   • Navigate to device Info & Metadata in Blynk.

• Assign the saved location to the device.

Step 8: Error Handling and Troubleshooting

8.1 Common Issues

1. Sensor Issues:
   • Check battery polarity and charge
   • Reset the sensor if unresponsive
2. Connectivity Problems:
   • Verify LoRaWAN settings and gateway connection
   • Test MQTT integration
3. Data Issues:
   • Check the payload formatter in TTN
   • If only the battery level is displayed or data is missing, go to TTN > Your Application > Payload Formatters > Uplink/Downlink, update the code, and save changes

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Uplink:

function decodeUplink(input) {
    var res = Decoder(input.bytes, input.fPort);
    if (res.error) {
        return {
            errors: [res.error],
        };
    }
    return {
        data: res,
    };
}
/**
 * Payload Decoder for The Things Network
 *
 * Copyright 2023 Milesight IoT
 *
 * @product WS302
 */
function Decoder(bytes, port) {
    return milesight(bytes);
}

function milesight(bytes) {
    var decoded = {};

    for (var i = 0; i < bytes.length; ) {
        var channel_id = bytes[i++];
        var channel_type = bytes[i++];

        // BATTERY
        if (channel_id === 0x01 && channel_type === 0x75) {
            decoded.battery = bytes[i];
            i += 1;
        }
        // SOUND
        else if (channel_id === 0x05 && channel_type === 0x5b) {
            decoded.freq_weight = readFrequecyWeightType(bytes[i]);
            decoded.time_weight = readTimeWeightType(bytes[i]);
            decoded.la = readUInt16LE(bytes.slice(i + 1, i + 3)) / 10;
            decoded.laeq = readUInt16LE(bytes.slice(i + 3, i + 5)) / 10;
            decoded.lamax = readUInt16LE(bytes.slice(i + 5, i + 7)) / 10;
            i += 7;
        }
        // LoRaWAN Class Type
        else if (channel_id === 0xff && channel_type === 0x0f) {
            switch (bytes[i]) {
                case 0:
                    decoded.class_type = "class-a";
                    break;
                case 1:
                    decoded.class_type = "class-b";
                    break;
                case 2:
                    decoded.class_type = "class-c";
                    break;
            }
            i += 1;
        } else {
            break;
        }
    }

    return decoded;
}

function readFrequecyWeightType(bytes) {
    var type = "";

    var bits = bytes & 0x03;
    switch (bits) {
        case 0:
            type = "Z";
            break;
        case 1:
            type = "A";
            break;
        case 2:
            type = "C";
            break;
    }

    return type;
}

function readTimeWeightType(bytes) {
    var type = "";

    var bits = (bytes[0] >> 2) & 0x03;
    switch (bits) {
        case 0:
            type = "impulse";
            break;
        case 1:
            type = "fast";
            break;
        case 2:
            type = "slow";
            break;
    }

    return type;
}

function readUInt16LE(bytes) {
    var value = (bytes[1] << 8) + bytes[0];
    return value & 0xffff;
}

function readInt16LE(bytes) {
    var ref = readUInt16LE(bytes);
    return ref > 0x7fff ? ref - 0x10000 : ref;
}

Next Steps

• Explore the Blynk Web Console and IoT app to monitor sensor data
• Read the Blynk Documentation to learn about Virtual Pins
• Learn how to Share Devices with other users
• Customize the code to meet your specific needs
• Try onboarding the sensor using static tokens