Multi-Connectivity IoT Starter with Blues Notecard

Blues - Multi-Connectivity IoT Starter

A single firmware, three-connectivity-type demo — Cellular, Wi-Fi, and LoRaWAN — powered by Blues Notecard and fully integrated with Blynk IoT. Includes a real-world setup with identical units deployed in the lab, in the field, and on the move. Tracks temperature, voltage, pressure, door status, and signal strength — with alerts and bi-directional control. Perfect for testing or deploying multi-network IoT solutions with zero backend setup.

Step 1: Understanding the Hardware Architecture

1.1 Core Components (Identical for All Three Devices)

• Blues Notecarrier F - Main development board with Feather-compatible slot
• Blues Swan (STM32-based) - Feather-compatible host microcontroller
• LiPo Battery - Power source for portable operation
• Reed Switch - Door open/close detection sensor
• SparkFun BMP581 Sensor - Temperature and barometric pressure measurement (Qwiic connection)

1.2 Variable Components (Different Notecard Types)

• Notecard Cellular - For cellular network connectivity
• Notecard Wi-Fi - For Wi-Fi network connectivity
• Notecard LoRa - For LoRaWAN network connectivity

1.3 Physical Installation

1. Mount the reed switch on the refrigerator door frame
2. Place the BMP581 sensor inside the refrigerator for accurate temperature readings
3. Position the main device externally for optimal connectivity
4. Ensure proper antenna placement based on the Notecard type being used

The main carrier/development board is the Notecarrier F (1). It has a slot for a Feather-compatible host (in this case the STM32-based Blues Swan) (2). The Notecarrier's power source is a small LiPo battery (3). The Notecard (4) is what can be swapped out for Cellular, Wi-Fi, or LoRa.

Step 2: Setting Up Blues Notehub

2.1 Creating Your Notehub Project

1. Sign up for Notehub at notehub.io
2. Create a New Project:
   • Project Name: Multi-Connectivity IoT Starter
   • Note the Product UID - you'll need this for device configuration

2.2 Getting Notehub API Credentials for Blynk Integration

You'll need these credentials later for the Blynk integration:

1. In your Notehub project, go to Settings → Programmatic API access
2. Copy the Client ID (format: e50cbb73-2074-4c03-9b3f-35140f850d6e)
3. Generate a Client Secret:
   • Click Generate button
   • Copy the secret immediately (it won't be displayed again)
   • Store it securely for the Blynk integration

2.3 Understanding Note Templates

Note templates optimize data transmission, especially for LoRa which is bandwidth-constrained. Two templates are required:

Sensor Data Template (fridge_sensors.qo):

{
 "voltage": 12.1,
 "temperature": 12.1,
 "pressure": 12,
 "bars": 12,
 "door_status": true,
 "_lat": 14.1,
 "_lon": 14.1
}

Alert Template (fridge_alert.qo):

{
 "alert": true
}


Step 3: Firmware Configuration

3.1 Download and Setup

1. Download the complete firmware
2. Install required libraries:
   • note-arduino SDK
   • SparkFun BMP581 Arduino Library
   • Standard Arduino libraries for I2C communication

3.2 Key Configuration Constants

// Update these values in your firmware
const char* PRODUCT_UID = "your-notehub-product-uid";
const char* WIFI_SSID = "your-wifi-network";
const char* WIFI_PASSWORD = "your-wifi-password";

// Timing constants
const unsigned long sensorReadPeriod = 30000; // 30 seconds default
const unsigned long doorOpenAlertPeriod = 10000; // 10 seconds


3.3 Universal Firmware Approach

The beauty of this project is using identical firmware across all three radio types. The Notecard automatically handles radio-specific commands:

// This works for all Notecard types
J *req = notecard.newRequest("hub.set");
JAddStringToObject(req, "product", PRODUCT_UID);
JAddStringToObject(req, "mode", "continuous");
JAddBoolToObject(req, "sync", true);
notecard.sendRequestWithRetry(req, 5);

// Wi-Fi config - ignored by Cellular and LoRa Notecards
req = notecard.newRequest("card.wifi");
JAddStringToObject(req, "ssid", WIFI_SSID);
JAddStringToObject(req, "password", WIFI_PASSWORD);
notecard.sendRequest(req);


Step 4: Sensor Data Collection

4.1 Battery Voltage Monitoring

// Get battery voltage from Notecard
J *req = notecard.newRequest("card.voltage");
J *rsp = notecard.requestAndResponse(req);
double voltage = JGetNumber(rsp, "value");


4.2 Cellular Signal Strength (Cellular Only)

// Get signal strength (bars) for cellular Notecard
req = notecard.newRequest("card.wireless");
rsp = notecard.requestAndResponse(req);
int bars = JGetInt(rsp, "bars");


4.3 Environmental Sensors

// Read temperature and pressure from BMP581
float temperature = bmp581.getTemperature();
float pressure = bmp581.getPressure();

// Read door status from reed switch
bool door_open = digitalRead(REED_SWITCH_PIN);


4.4 Data Transmission

// Send sensor data to Notehub
J *req = notecard.newRequest("note.add");
JAddStringToObject(req, "file", "fridge_sensors.qo");
JAddBoolToObject(req, "sync", true);
J *body = JAddObjectToObject(req, "body");
JAddNumberToObject(body, "voltage", voltage);
JAddNumberToObject(body, "temperature", temperature);
JAddNumberToObject(body, "pressure", pressure);
JAddNumberToObject(body, "bars", bars);
JAddBoolToObject(body, "door_status", door_open);
notecard.sendRequest(req);


Step 5: Door Alert System

5.1 Alert Logic

The system monitors door status and sends alerts when doors are left open beyond the threshold:

if (door_open && !alert_sent &&
   currentMillis - startMillisAlert >= doorOpenAlertPeriod) {

   J *req = notecard.newRequest("note.add");
   JAddStringToObject(req, "file", "fridge_alert.qo");
   JAddBoolToObject(req, "sync", true);
   J *body = JAddObjectToObject(req, "body");
   JAddBoolToObject(body, "alert", true);
   notecard.sendRequest(req);

   alert_sent = true;
}


5.2 SMS Notifications (Optional)

Follow the Blues Twilio SMS Guide to set up automatic SMS alerts when doors are left open.

Step 6: Blynk Integration Setup

6.1 Using the Pre-Built Multi-Connectivity IoT Starter Template

6.1.1 Access the Blueprint Template

1. Click "Use Blueprint" at the top of this Multi-Connectivity IoT Starter blueprint page
2. The Multi-Connectivity IoT Starter will be automatically added to your Blynk account

6.1.2 Template Overview

The pre-built template includes:

Pre-configured Datastreams:

• V0: Battery Voltage (0-5V)
• V1: Temperature (-20 to 50°C)
• V2: Pressure (800-1200 hPa)
• V3: Signal Bars (0-5 bars)
• V4: Door Status (0=closed, 1=open)
• V5: Sync Frequency (10-300 seconds)
• V6: Alert Status (0=normal, 1=alert)

Pre-designed Dashboard Widgets:

• Battery voltage gauge with color coding
• Temperature gauge with freeze warnings
• Signal strength indicator (cellular only)
• Door status LED indicator
• Real-time alert banner
• Historical charts for trends
• Bi-directional sync frequency slider

6.2 Set Up Blues Integration in Blynk

1. Navigate to Integrations in your Blynk Console
2. Click "Add New Integration"
3. Select "Blues" from the available integrations
4. Configure the Blues Integration:Connection Settings:
   • CLIENT ID: Copy from your Notehub project settings (from Step 2.2)
     • Go to your Notehub project → Settings → Programmatic API access
     • Copy the Client ID (format: e50cbb73-2074-4c03-9b3f-35140f850d6e)
   • CLIENT SECRET: Generate in Notehub (from Step 2.2)
     • In the same Programmatic API access section
     • Click Generate to create a new client secret
     • Copy the generated secret immediately (it won't be shown again)
   Data Mapping:
   • The integration will automatically map Blues Products with Blynk Templates
   • Select your Multi-Connectivity IoT Starter template for data mapping

5. Click "Connect" to establish the integration
6. Verify Connection: The status should show "Connected" with a green indicator

Note: If you see "Broken" status, double-check that:

• Your Client ID and Client Secret are correct
• Your Notehub project has devices sending data
• The API access is properly configured in Notehub

6.3 Data Mapping Configuration

Once the Blues integration is connected, configure the data mapping:

1. In the Data Mapping section, you'll see your Notehub products
2. Map your product to the Multi-Connectivity IoT Starter template
3. The mapping will automatically handle:
   • Device creation from Notehub device names
   • Data routing from Notes to Blynk datastreams
   • Bi-directional communication for remote configuration

6.4 Verify Integration

1. Check Integration Status: Should show "Connected"
2. Monitor Data Flow:
   • Send test data from your Notecard
   • Verify data appears in Blynk devices
   • Check that all datastreams are receiving values correctly

Troubleshooting: If integration shows "Broken":

• Verify Client ID and Secret are correct
• Ensure your Notehub project has active devices
• Check that devices are sending the expected Note files (fridge_sensors.qo, fridge_alert.qo)

Step 7: Device Management and Monitoring

7.1 Automatic Device Creation

With the Blues integration properly configured, devices will be automatically created in Blynk when they first send data:

1. Devices appear automatically when Notecards send their first Notes
2. Device names match the Notecard device names from Notehub:
   • Cellular Fridge
   • WiFi Fridge
   • LoRa Fridge
3. All datastreams are automatically populated with sensor data

7.2 Manual Device Creation (If Needed)

If automatic creation doesn't work, you can manually create devices:

1. Navigate to Devices in Blynk Console
2. Click "New Device"
3. Select "From Template" → "Multi-Connectivity IoT Starter"
4. Enter device details:
   • Device Name: Match your Notehub device name exactly
   • Auth Token: Will be auto-generated
5. Save the device

7.3 Dashboard Overview

The pre-built dashboard provides comprehensive monitoring capabilities:

Real-time Monitoring:

• Battery voltage gauge with color-coded warnings
• Temperature display with freeze alerts
• Signal strength indicator (cellular devices only)
• Door status LED (green=closed, red=open)
• Alert banner appears when door left open too long

Historical Data:

• Temperature trends over time
• Battery discharge patterns
• Door opening frequency analysis
• Signal quality history (cellular devices)

Interactive Controls:

• Sync frequency slider to adjust data transmission rate
• Time range selectors for historical charts
• Device selection to switch between multiple fridges

Step 8: Bi-Directional Communication

8.1 Understanding Inbound Data

Blynk can send configuration changes back to your devices through the Blues integration. This creates inbound Notes (.qi files) that your firmware can process.

8.2 Remote Configuration Updates

The bi-directional communication allows you to:

1. Adjust sync frequency from the Blynk dashboard
2. Update sensor thresholds remotely
3. Enable/disable features without firmware updates
4. Send commands for diagnostic purposes

8.3 Processing Configuration Updates in Firmware

void updateSensorCadence() {
   // Check for inbound data from Blynk that will set the sensor cadence
   J *req = notecard.newRequest("file.changes");
   J *files = JAddArrayToObject(req, "files");
   JAddItemToArray(files, JCreateString("blynk.qi"));

   J *rsp = notecard.requestAndResponse(req);
   int total = JGetNumber(rsp, "total");

   if (total > 0) {
       // Get and process the inbound note
       req = notecard.newRequest("note.get");
       JAddStringToObject(req, "file", "blynk.qi");
       JAddBoolToObject(req, "delete", true);

       rsp = notecard.requestAndResponse(req);
       J *body = JGetObject(rsp, "body");

       if (JGetNumber(body, "Sync Freq")) {
           sensorReadPeriod = 1000 * JGetNumber(body, "Sync Freq");
       }
   }
}


Step 9: Device Deployment and Testing

9.1 Device Identification

Set unique device names in Notehub for easy identification:

• Cellular Fridge
• Wi-Fi Fridge
• LoRa Fridge

9.2 Testing Connectivity

1. Cellular Device: Verify cellular connection and signal strength reporting
2. Wi-Fi Device: Confirm Wi-Fi network connection and data transmission
3. LoRa Device: Ensure LoRaWAN gateway connectivity and template optimization

9.3 Sensor Calibration

1. Temperature accuracy: Compare BMP581 readings with known reference
2. Door sensor: Test reed switch positioning for reliable open/close detection
3. Battery monitoring: Verify voltage readings match actual battery levels

Step 10: Advanced Features and Monitoring

10.1 Location Tracking

For cellular devices, automatic location data is included:

• Cell tower triangulation provides approximate location
• Timezone detection for accurate timestamps
• Country and region identification

10.2 Data Analytics

Monitor key metrics in Blynk:

• Average door opening frequency
• Temperature trend analysis
• Battery discharge patterns
• Connectivity reliability across different radio types

10.3 Maintenance Alerts

Set up additional automations for:

• Low battery warnings (< 3.3V)
• Temperature threshold alerts (freezer too warm)
• Connectivity loss notifications
• Extended door-open incidents

Step 11: Troubleshooting and Optimization

11.1 Common Issues

• No data transmission: Check Notehub Product UID and network connectivity
• Inaccurate temperature: Verify BMP581 sensor placement and calibration
• Missed door events: Adjust reed switch positioning and debounce logic
• Short battery life: Optimize sensor reading frequency and sleep modes

11.2 Performance Optimization

• LoRa optimization: Use templates and minimize payload size
• Cellular data management: Monitor data usage to stay within 500MB limit
• Battery optimization: Implement deep sleep between sensor readings
• Alert optimization: Prevent alert flooding with proper state management

11.3 Scaling Considerations

• Multiple refrigerators: Use fleet management in Notehub
• Different sensor types: Expand template to include additional sensors
• Custom alerts: Implement complex alert logic based on multiple conditions
• Integration expansion: Connect to additional cloud platforms as needed

Step 12: Security and Best Practices

12.1 Security Features

• Device authentication: Automatic secure pairing with Notehub
• Data encryption: All transmissions encrypted by default
• Certificate management: Handled automatically by Blues infrastructure

12.2 Best Practices

• Regular firmware updates: Keep note-arduino SDK updated
• Battery maintenance: Monitor and replace batteries proactively
• Network redundancy: Consider multiple connectivity options for critical applications
• Data retention: Configure appropriate data retention policies in Notehub

Next Steps

• Explore automations: set up triggers, alerts, and workflows without writing code
• Mass provision devices with Static Tokens
• Scale your deployment with organizations, and role-based access
• Customize web and mobile dashboards to match your specific use case and user roles
• Try satellite connectivity with Notecard Satellite.

Resources and Documentation

• Blues Developer Documentation
• Notecard API Reference
• Blynk Blues Integration Guide
• Complete Project Source Code

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