LoRa Basics™ Modems: Walk-through

Application Server: Node-RED

The application server handles application data and device management frames. There is no background connection between the LoRaWAN® network server and the LoRa Cloud™ Device & Application Services. Rather, all uplinks related to modem traffic must be forwarded by the application server to the Lora Cloud Device & Application Services server.

This demonstration uses Node-RED as the application server. Node-RED is a browser-based visual programming tool that allows for fast prototyping. Built on Node.js, Node-RED can be used to wire flows together using a wide array of nodes. These nodes can then be deployed to the Node-RED runtime with a single click.

Setup

Installation

To set up Node-RED, follow the instructions in the official installation guide, available here: https://nodered.org/docs/getting-started/. You can use a local computer, a Raspberry Pi, or any remote computer/server.

Accessing the Node-RED Editor

By default, Node-RED starts on port 1880. If you have installed Node-RED locally, browse to http://127.0.0.1:1880; otherwise navigate to http://IP_OF_INSTALLATION:1880.

Once Node-RED is set up correctly, the following page displays:

Node-RED editor

Figure 1: Node-RED editor

The user interface has three key areas:

  • Palette: This is where you can select nodes; these are functional blocks that can be dragged-and-dropped, and then can be linked together to create a flow.

  • Flow: This is the source code of the program. In this pane, you can link nodes together to create an application.

  • Sidebar: The Sidebar displays any Help or debugging information available for the selected node.

Installing Additional Nodes

To set up the demonstration, three additional libraries must be installed in Node-RED:

To set up Node-RED, use the Node-RED editor menu, as shown in the following video:

Video: Installing Additional Nodes

To set up Node-RED:

  1. Click the hamburger menu in the top right corner of the screen.

  2. Select Manage palette.

  3. Select Install.

  4. Search for node-red-contrib-loracloud-utils.

  5. Click Install for the @semtech-wsp-apps/node-red-contrib-loracloud-utils package.

  6. In the dialog box that pops-up, click Install.

  7. Wait for the installation to complete. This might take several minutes.

  8. Repeat these steps to install the node-red-dashboard and the node-red-contrib-web-worldmap libraries.

Import the LoRa Basics™ for End Nodes Demo Flow

The node-red-contrib-loracloud-utils package includes useful samples to walk you through this example project. Watch this video to learn how to import them:

Video: Import Samples for Demo

To import the example flow:

  1. Click the hamburger menu in the top right corner of the screen.

    1. Click Import.

    2. Click Examples.

    3. Select node-red-contrib-loracloud-utils and then modem.

    4. Select New flow then click Import.

  2. Place the nodes and then left-click to save their positions.

  3. Deploy the flow by pressing the Deploy button on the device.

  4. Dismiss the error by clicking Confirm deploy.

Note

The Deploy step reports an error because the MQTT nodes are not yet configured.

Configure the Flow

The example flow must be configured with the device information and the selected LoRaWAN network server.

Configuring the LoRaWAN Network Server (MQTT)

All network server connectors are activated by default; however, the MQTT connection must be set up separately.

Before you begin, get the required data:

  • MQTT server address

  • MQTT port

  • MQTT username

  • MQTT password

This data can be obtained when setting up the network server. For more information, see Network Server Setup.

Next, set up the desired network server:

Video: Setting up a Network Server

  1. Delete the MQTT connectors to any unused LoRaWAN network servers.

  2. Double-click an MQTT node to edit it.

  3. Click the pencil icon to edit the MQTT broker configuration.

  4. Enter values in the Server, Port, and TLS fields, if required.

  5. On the Security tab, fill in the Username and Password fields.

  6. Click Add and then click Done.

  7. Click Add new mqtt-broker in the other nodes to select the server.

  8. Click Deploy.

Note

Several LoRaWAN network servers can be used at a time.

LoRa Cloud Configuration

To configure the server, the DAS URL and DAS TOKEN values from the LoRa Cloud Device & Application Services setup step, are required, as is the device’s DevEUI.

Video: Configuration of DAS server connection

To configure the LoRa Cloud services for your use:

  1. Double-click the DAS server token node to open it for editing.

  2. Enter the token and then click Done.

  3. Open the DAS URL node for editing.

  4. Enter the URL and then click Done.

  5. Open the DevEUIs URL node for editing.

  6. Enter the DevEUIs and then click Done.

  7. Click Deploy.

Note

  • Several DevEUIs can be configured at once

  • The characters for each DevEUI should be separated into groups of two, with a dash between each pair: XX-XX-XX-XX-XX-XX-XX-XX

Configuring Node-RED User Interface Elements

Node-RED user interface (UI) elements must be associated with a UI group. The following steps create an association with the default Node-RED UI group.

Video: Associating Node-RED UI elements with a UI group

To associate a Node-RED UI element with a UI group:

  1. Select Temperature widget.

    1. Click the pencil icon to edit the widget.

    2. Click Update.

    3. Click Done.

  2. Repeat these steps for the Upload text widget and the Image widget.

Import the LoRa Basics Modem-E Flow Add-on

Once the LoRa Basics for end nodes flow has been set up, you need to import an add-on to see the geolocation features of the LR1110 in action.

Video: Importing LR1110 geolocation example

To import the add-on:

  1. Click the hamburger menu in the top right corner of the screen.

    1. Click Import.

    2. Click Examples.

    3. Select node-red-contrib-loracloud-utils then select Modem-E.

    4. Select New flow and then click Import.

  2. Place the nodes and then left-click to save their positions.

  3. Double-click the blue node, Assistance coordinates for GNSS autonomous scans, to open it for editing.

  4. Set the assistance coordinates [latitude, longitude] and then click Done.

  5. Double-click the grey input link to edit it.

  6. Check the Stream from DAS box and then click Done. This flow then connects to all streams from the LoRa Cloud™ Device & Application Services.

  7. Double-click the grey output link to edit it.

  8. Check the To the Lora Cloud Device & Application Services parser box and then click Done. The LoRa Cloud Device & Application Services output connects to the LoRa Cloud Device & Application Services parser block.

  9. Press the Deploy button on the device to deploy the flow.

Note

Rough assistance coordinates are required by the solver for autonomous GNSS scans, and must have an accuracy of ± 150km. See the reference manual for a complete description.

Usage

Temperature

Temperature is sent automatically from the Murata modem when in Demo mode.

Note

If using a Nucleo board, you must press the blue button on the board itself to send the temperature data.

To display the dashboard

Add /ui to the URL in your web browser. (For example, if Node-RED is installed locally, use the URL http://127.0.0.1:1880/ui.)

The temperature graph displays:

Application server temperature graph

Figure 2: Temperature graph available via the application server

Uploading a File

LoRa Basics Modem sends images through the File Upload service. The images are then reconstructed by the LoRa Cloud Device & Application Services. Once it has been fully received, the image displays in the Node-RED user interface, as shown here:

Image in the application server for file upload

Figure 3: Image uploaded with File Upload service

Note

The LoRa Basics Modem serial output displays INFO : File upload is complete, program a new alarm when a file transfer is complete.

Data Returned by the LoRa Cloud Device & Application Services

The Node-RED sidebar shows all data returned by the LoRa Cloud Device & Applications Services server. To view this data, click Debug, which is represented with an insect icon):

Node-RED debug button

Figure 4: Node-RED debug button

The data displayed looks like this:

Data from the LoRa Cloud Device & Application Services displayed in the debug sidebar

Figure 5: Data from the LoRa Cloud Device & Application Services displayed in the debug sidebar

Warning

If some of the fragments of a stream are lost due to network issues, the subsequent streams are kept in the LoRa Cloud Device & Application Services’ memory.

These streams will be delivered to the application server as soon as they have been reconstructed. This may result in the stream being delivered out of order.

Sending a Request to the End Node Through the LoRa Cloud Device & Application Services

The LoRa Cloud Device & Application Services server provides an easy way to send requests to the end node to get information or update configuration data. This can be tested by clicking the square buttons adjacent to the blue nodes in the Direct API calls section of the Node-RED example.

To send a request to the LoRa Cloud Device & Application Services

Click the blue button to the left of the associated box, as shown in Figure 6:

Request to LoRa Cloud Device & Application Services buttons

Figure 6: Request to LoRa Cloud Device & Application Services Buttons

Note

The full request list can be found here.

Geolocation (LoRa Basics Modem-E)

Geolocation results are displayed on a map and in Node-RED’s debug tab.

To display the map, add /worldmap to the URL in your web browser. For example, if Node-RED is installed locally, use the URL http://127.0.0.1:1880/worldmap).

Geolocation map

Figure 7: Geolocation map

Note

The worldmap does not save location data. All points are lost when the page is closed.

LoRaWAN Class C (LoRa Basics Modem-E)

To be able to send downlink requests to the LoRaWAN network server provider, the application server must know which LoRaWAN network server the device is connected to. For Class A downlinks, the uplink information is propagated from the uplink connector to the downlink connector along with the message. However, in the case of Class C devices, the downlink is generated without an uplink event, so this information does not exist.

LoRaWAN Network Server Storage

The section Network Server context, which is part of the modem flow, features local data storage for devices’ LoRaWAN network server information. It behaves as follows:

  • On every uplink, the network server information of the device is stored in a local data strucuture.

  • When a Class C downlink is requested, the network server information for the device is extracted from this local data structure.

  • The message to downlink and the network server information are provided to the downlink connector.

This mechanism is implemented by the Network Server context flow, which is available as an example and illustrated here:

Network Server context flow diagram

Figure 8: Network server context flow overview

The node Update network server configuration storage receives all uplinks that are destined for the LoRa Cloud Device & Application Services and stores the network server information.

Downlink message Node Red blocks picture

Figure 9: Generate downlink message node

The node Generate downlink message retrieves the network server information when a downlink is requested. This flow allows the network server to read and clean the content of the local data structure.

The content is displayed in the debug panel when Read LoRaWAN Network Server configuration is clicked.