node-red-contrib-chirpstack-multicast

Node-RED node for sending multicast downlinks to ChirpStack v4 LoRaWAN network server. This node was generated using claude.ai

Features

• ✅ Send multicast downlinks to groups of LoRaWAN devices
• ✅ Support for ChirpStack v4.x (gRPC API)
• ✅ Multiple data format support (Buffer, Hex, Base64, UTF-8)
• ✅ Cayenne LPP compatible
• ✅ Debug mode for troubleshooting
• ✅ Complete error handling

Installation

npm install node-red-contrib-chirpstack-multicast

Or install directly from Node-RED's palette manager.

Requirements

• Node-RED >= 2.0.0
• ChirpStack v4.x
• LoRaWAN devices in Class C mode
• Configured multicast group in ChirpStack

Configuration

1. Add ChirpStack Server Configuration

1. Drag the chirpstack-multicast node into your flow
2. Double-click to configure
3. Create a new server configuration:
   • Server: Your ChirpStack server address (e.g., localhost:8080)
   • API Token: Your ChirpStack API key

2. Configure Multicast Node

• Name: Optional node name
• Server: Select your ChirpStack server
• Group ID: Multicast group ID (optional, can be provided via msg)
• fPort: LoRaWAN application port (default: 10)
• Debug: Enable debug logging

Usage

Basic Example

msg.multicastGroupId = "4820fc7f-0579-46a6-a67f-96d46e2c0cd7";
msg.fPort = 10;
msg.payload = "Hello World";
return msg;

Send Buffer

msg.multicastGroupId = "4820fc7f-0579-46a6-a67f-96d46e2c0cd7";
msg.payload = Buffer.from([0x01, 0x02, 0x03, 0x04]);
return msg;

Send Hex String

msg.payload = "48656C6C6F";  // "Hello" in hex
return msg;

Cayenne LPP Example

// Temperature sensor (channel 1)
const buf = Buffer.alloc(4);
buf[0] = 1;     // Channel
buf[1] = 0x67;  // Temperature type
buf[2] = 0x01;  // Value high byte (25.6°C)
buf[3] = 0x00;  // Value low byte

msg.multicastGroupId = "your-group-id";
msg.payload = buf;
return msg;

Complete Weather Station Example

function encodeCayenneLPP(temp1, temp2, hum1, hum2) {
    const buf = Buffer.alloc(14);
    let i = 0;
    
    // Channel 1 - Temperature
    buf[i++] = 1; buf[i++] = 0x67;
    let t1 = Math.round(temp1 * 10);
    buf[i++] = (t1 >> 8) & 0xFF; 
    buf[i++] = t1 & 0xFF;
    
    // Channel 2 - Temperature
    buf[i++] = 2; buf[i++] = 0x67;
    let t2 = Math.round(temp2 * 10);
    buf[i++] = (t2 >> 8) & 0xFF; 
    buf[i++] = t2 & 0xFF;
    
    // Channel 3 - Humidity
    buf[i++] = 3; buf[i++] = 0x68;
    buf[i++] = Math.round(hum1 * 2);
    
    // Channel 4 - Humidity
    buf[i++] = 4; buf[i++] = 0x68;
    buf[i++] = Math.round(hum2 * 2);
    
    return buf;
}

msg.multicastGroupId = "4820fc7f-0579-46a6-a67f-96d46e2c0cd7";
msg.fPort = 10;
msg.payload = encodeCayenneLPP(25.5, 22.3, 65, 58);
return msg;

Input

msg.multicastGroupId

Type: string
Required: Yes (if not configured in node)
The UUID of the multicast group in ChirpStack.

msg.fPort

Type: number
Required: No (default: 10)
LoRaWAN application port (1-223).

msg.payload

Type: Buffer | string | object
Required: Yes
The data to send. Supports:

• Buffer: Raw binary data
• Hex string: "48656C6C6F"
• Base64 string: "SGVsbG8="
• UTF-8 string: "Hello"

Output

msg.payload (Success)

{
  "success": true,
  "fCnt": 42,
  "multicastGroupId": "4820fc7f-0579-46a6-a67f-96d46e2c0cd7",
  "fPort": 10,
  "timestamp": "2024-11-05T10:30:00.000Z"
}

msg.payload (Error)

{
  "success": false,
  "error": "Error message"
}

Supported Data Formats

| Format | Example | Detection | |--------|---------|-----------| | Buffer | Buffer.from([0x01, 0x02]) | Buffer.isBuffer() | | Hex | "48656C6C6F" | Regex: ^[0-9A-Fa-f]+$ | | Base64 | "SGVsbG8=" | Regex: ^[A-Za-z0-9+/=]+$ | | UTF-8 | "Hello World" | Default fallback |

ChirpStack Configuration

Create Multicast Group

1. In ChirpStack web interface, go to Applications
2. Select your application
3. Click Multicast groups → Create
4. Configure:
   • Name: Your group name
   • Region: EU868, US915, etc.
   • Multicast address: 4-byte address
   • Network session key (McNwkSKey)
   • Application session key (McAppSKey)
   • Frame counter: Start at 0
   • Data rate: Compatible with all devices
   • Frequency: RX2 frequency for your region

Add Devices to Group

1. Go to your multicast group
2. Click Add device
3. Select devices (must be Class C)

Configure Devices for Class C

Your LoRa-E5 modules must be in Class C:

AT+CLASS=C

Troubleshooting

"Multicast Group ID manquant"

• Ensure multicastGroupId is set in node configuration or msg

"Erreur gRPC"

• Check ChirpStack server address (default: localhost:8080)
• Verify API token is valid
• Check ChirpStack logs: docker logs -f chirpstack

Devices not receiving

• Verify devices are in Class C mode
• Check devices are members of the multicast group
• Verify multicast group frequency and data rate
• Check ChirpStack gateway connection

Debug Mode

Enable debug mode in node configuration to see:

• Multicast Group ID
• fPort
• Data (hex and base64)

Example Flow

[{"id":"inject1","type":"inject","name":"Test Multicast","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":140,"y":100,"wires":[["function1"]]},{"id":"function1","type":"function","name":"Prepare Data","func":"msg.multicastGroupId = \"4820fc7f-0579-46a6-a67f-96d46e2c0cd7\";\nmsg.fPort = 10;\nmsg.payload = Buffer.from(\"Hello\");\nreturn msg;","outputs":1,"x":310,"y":100,"wires":[["multicast1"]]},{"id":"multicast1","type":"chirpstack-multicast","name":"Send Multicast","server":"server1","multicastGroupId":"","fPort":10,"debug":true,"x":500,"y":100,"wires":[["debug1"]]},{"id":"debug1","type":"debug","name":"Response","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","x":680,"y":100,"wires":[]}]

API Reference

gRPC Service

Uses ChirpStack's MulticastGroupService.Enqueue method.

Protobuf Definition

service MulticastGroupService {
  rpc Enqueue(EnqueueMulticastGroupQueueItemRequest) returns (EnqueueMulticastGroupQueueItemResponse);
}

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Submit a pull request

License

MIT License - see LICENSE file for details

Author

Votre Nom

Links

• GitHub Repository
• npm Package
• ChirpStack Documentation
• Node-RED

Changelog

1.0.0

• Initial release
• Support for ChirpStack v4.x
• Multiple data format support
• Debug mode