How To Build a Location Tracker for Cellular and LoRaWAN Connections

Location tracking devices are today used in a lot of scenarios. Be it cargo, package, logistic truck tracking, or in other applications. One of the challenges for such devices is the connectivity. LoRaWAN provides low-power long-range communication but depends on the coverage with LoRaWAN gateways. The cellular connection provides wide coverage, but it consumes more energy, which influences the lifetime of battery-powered devices.

The ideal solution is to have a device that has both connectivity, LoRaWAN, and cellular connections. The cellular modem can work as a backup for the LoRaWAN transceiver if the device is out of range of LoRaWAN gateways.

With the WisBlock RAK13102 IO module RAKwireless is now offering an easy-to-use and cost-effective solution to build such a dual-connectivity location tracker. Partnering with Blues.IO (opens new window)we designed the RAK13102 to work with any of the Notecard Cell+Wifi (opens new window)modules. These cellular modules provide worldwide coverage and come with 500 MB of free cellular data.

The beauty of using the Blues Notecard is that you set up the cellular modem with simple JSON formatted requests instead of learning complicated AT commands (that are different between different suppliers and modem chips). Blues has a very good documentation (opens new window)for these JSON formatted strings, and if you look into the source code (opens new window)that is used in this tutorial, you can see how easy this can be implemented in your application code.

Read on to learn how easy it is to use the Blues.IO Notecards and build a dual-connectivity device.

WisBlock Goes Blues

While WisBlock is usually associated with LoRa and LoRaWAN, this time we are diving into the cellular data transmission using the Blues.IO NoteCard. This project is about building a location tracker that can connect to both LoRaWAN and a cellular connection with a Blues NoteCard.

Setup the WisBlock Blues Location Tracker

Hardware

The only thing that requires some work is to set up the WisBlock system with the Blues NoteCard using the RAK13102 NoteCarrier. The RAK13102 plugs into the WisBlock Base Board IO slot, so you can only use any of the following base boards:

• RAK19007
• RAK19001
• RAK19010
• RAK19011

The RAK13102 module blocks the Sensor Slots A and B, but it has a mirror of these two slots, so they still can be used. Optionally, you can add a RAK1906 environment sensor to the WisBlock Base Board.

The code provided in the GitHub repository supports beside of the communication to the Blues NoteCard, the LoRaWAN connection and a RAK1906 environment sensor.

For this tutorial, a 3D printed enclosure is used.

The enclosure is printed with PLA+ and the STEP files are available in the GitHub repo, where you can find as well the code for this tutorial.

But for an outdoor application RAKwireless is offering the pre-assembled Blues.ONEdevice in our IP65 Unify Enclosure.

Setting Up Your Notecard

You have to setup your Notecard at Blues.IO before it can be used. There are two options to setup the Notecard:

1. Follow the Quickstartguides provided by Blues.
2. Set up the device with AT commands directly through the WisBlock's USB.

Setup Through the USB of the RAK13102 Notecard

Connect the RAK13102 Notecarriers USB to your computer. WisBlock has to be powered separate, and then use the Blues Quickstart.

Setup Through AT Commands

Connect the WisBlock USB port to your computer and connect a serial terminal application to the COM port.

Setup the Product UID

To connect the Blues Notecard to the NoteHub, a Product UID is required. This product UID is created when you create your project in NoteHub, as shown in Set Up Notehubsection.

1. Get the Product UID from your NoteHub project.
2. Use the ATC+BEUI command to save the Product UID in the WisBlock: ATC+BUID=com.my-company.my-name:my-project
3. Replace com.my-company.my-name:my-project with your project EUI.
4. The current product UID can be queried with ATC+BUID=?.

Select SIM Card

There are two options for the Blues Notecard to connect. The primary option is to use the eSIM that is already on the Notecard. However, there are countries where the eSIM is not working yet. In this case, you need to use an external SIM card in the RAK13102 WisBlock module. This can be a SIM card from your local cellular provider or an IoT data SIM card, for example, a SIM card from Monogotoor another provider.

Use the AT command ATC+BSIM to select the SIM card to be used.

Syntax: ATC+BSIM=<SIM>:<APN>

• <SIM> == 0 to use the eSIM of the Notecard only
• <SIM> == 1 to use the external SIM card of the RAK13102 Notecarrier only
• <SIM> == 2 to use the external SIM card as primary and the eSIM of the Notecard as secondary
• <SIM> == 3 to use the external SIM card as secondary and the eSIM of the Notecard as primary

If the external SIM card is selected (<SIM> is 1, 2, or 3), the next parameter is the APN that is required to connect the Notecard. <APN>: For example, the internet to use with the Filipino network provider SMART.

Several carriers will have a website dedicated to manually configuring devices, while others can be discovered using APN discovery websites like apn.how.

The current settings can be queried with AT+BSIM=?.

Select Notecard Connection Mode

The Blues Notecard supports different connection modes. For testing purposes, it might be required to have the NoteCard connected continuously to the cellular network, but in a battery-powered application, the preferred connection type would be minimal, which connects to the cellular network only when data needs to be transferred.

The connection mode can be set up with the AT command AT+BMOD.

Syntax: AT+BMOD=<mode>

• <mode> == 0 to use the minimal connection mode
• <mode> == 1 to use the continuous connection mode
• The default is to use minimal connection mode.
• The current status can be queried with AT+BMOD=?.

Select Notecard Location Send Trigger

There are two location transmission modes: defined timer intervals or triggered by the motion of the device. The transmission mode can be set with the AT+BTRIG command.

Syntax: AT+BTRIG=<mode>

• <mode> == 0 to use the time interval set with the AT command AT+SENDINT
• <mode> == 1 to use the continuous connection mode
• The default is to use time interval mode.
• The current status can be queried with AT+BTRIG=?.

Delete Blues Notecard Settings

If required all stored Blues NoteCard settings can be deleted from the WisBlock Core module with the AT+BR command.

Syntax: AT+BR

Reset Blues Notecard to Factory Settings

If required, the Blues NoteCard can be reset to factory default.

All saved settings like Product UID, connection settings, APN in the NoteCard WILL BE ERASED

Syntax: AT+BRES

Get Blues Notecard Status

Show NoteCard connection status with req:hub.status.

Syntax: AT+BLUES

Send Request to the Notecard

Sends a simple request to the Notecard and returns the response from the Notecard.

Syntax: AT+BREQ=<request>

• <request> is the Notecard request, for example, card.version or card.location.

LoRaWAN Setup

Besides the cellular connection, you need to set up as well the LoRaWAN connection. The WisBlock solutions can be connected to any LoRaWAN server like Helium, Chirpstack, TheThingsNetwork, or others.

On the device itself, the required setup with AT commands is:

        // Setup AppEUI
AT+APPEUI=70b3d57ed0abcdef
        // Setup DevEUI
AT+DEVEUI=ac1f09fffabcdef
        // Setup AppKey
AT+APPKEY=2b84e0b09b68e5cb42176fe753abcdef
        // Set automatic send interval in seconds
AT+SENDINT=60
        // Set data rate
AT+DR=3
        // Set LoRaWAN region (here US915)
AT+BAND=5
        // Reset node to save the new parameters
ATZ
        // After reboot, start join request
AT+JOIN=1,0,8,10

A detailed manual for the AT commands are in the AT-Command-Manual.

Using the WisBlock Blues Tracker

Once the WisBlock Blues Tracker is set up for both cellular and LoRaWAN connections, it will connect to the cellular network and join the LoRaWAN server. Independent of a successful connection, it will start acquiring location data using the GNSS engine that is built into the Notecards cellular modem.

The current application is a work in progress and only sends data at specified time intervals, not based on movement. The send interval can be set using an AT command.

ATC+SENDINT=300: Set the send interval to 300 seconds.

The current send interval can be queried with ATC+SENDINT=?.

WisBlock Blues Tracker in Action

LoRaWAN Server

For testing, Chirpstack V4 is used as a LoRaWAN server. The tracker has to be set up with its DevEUI and AppEUI in an application on the Chirpstack LNS. Optionally, you can add a payload decoder in the Device Profile, and then view the decoded payload in the events list of the device.

Here is an example log output with the result of the CayenneLPP data parson the LNS before it is sent to the Blues NoteHub:

Within the Chirpstack LNS application, integration is needed to forward the data to Datacake, used for visualization. The integration is a simple webhook to Datacake.

You can use other LoRaWAN servers like TTN or Helium for the device's LoRaWAN connection. For the location visualization, only the Datacake solution is explained here. If you want to use another location visualization, you need to figure out how to connect one device through both LoRaWAN and cellular connections.

Blues Notehub

The notes sent to the Blues Notehub can be seen in the Events listing of the Notehub.

The location and sensor data are sent as binary payloads, so there is nothing to see in the body field.

The next step is to create the Route in NoteHub that forwards the data to Datacake. Instead of the default URL for the Datacake route, use the URL for LoRaWAN devices. The note you want to forward is the data.qo note.

Because of the different formats, this guide uses a very appreciated feature available in the NoteHub Routes, the JSONata Expression. With this data transformation option, you will make the JSON packet coming from the NoteHub look like a packet coming from a LoRaWAN server. Read the Blues documentation about JSONata to understand how it works.

The JSONata expression needed is very simple and simulate a LoRaWAN packet format with just a few JSON fields:

{
    "deviceInfo": {
       "tenantName":"ChirpStack",
       "devEui": body.dev_eui
    },
    "fPort": 6,
    "data": payload
}

In the Route setup, scroll down to the Data section. Select JSONata Expression to transform the data, then copy-paste the JSONata Expression into the entry field.

The JSONata is pulling the required information from the Blues JSON data packet to build the fake LoRaWAN packet. You can check the functionality with the JSONata Exerciser:

The resulting JSON object is then sent to Datacake, which handles it as if it comes from a LoRaWAN server.

The routing events are shown in the Routes log view:

Datacake

To visualize the data in Datacake, a matching device has to be defined. As the data can come from two different paths, but you have transformed the packet forward in NoteHub to look like a LoRaWAN packet. Keep in mind that the the device must be a LoRaWAN device.

To distinguish whether the data is coming from the LNS or NoteHub, a different fPort is used in the packets. fPort 5 ==> data coming from the LNS fPort 6 ==> data coming from NoteHub (see above in the JSONata expression that it sets the fPort to 6)

The payload decoder used in this guide can be found in the file Decoder.js in the Github repository. The content of this file has to be copied into the Payload Decoder of the device configuration in Datacake:

The matching fields for the sensor data have to be created. The easiest way to do this is to wait for incoming data from the sensors. If no matching field is existing, the data will be shown in the Suggested Fields list in the configuration.

The sensor data can be easily assigned to fields using the Create Field button.

It will take some time before the suggested fields are listed as complete. Instead of using the suggested fields, you can just create the following fields manually:

Once all the sensor data is assigned to fields, you can start with the visualization of the data.

In Datacake, each device has its own Device Dashboard which we will use to display the location data. I will not go into details on how to create visualization widgets in Datacake, this step is handled in other tutorials already.

In the final result for the WisBlock Blues Tracker, you can see life data on my public dashboard.The top part of the dashboard are the locations of the device (history enabled) on the map. The device sensor values on the side, temperature and humidity, are only available if a RAK1906 is present.

In the lower part, a chart shows at what times the sensor used LoRaWAN to transmit data and when it used the cellular connection:

Bernd Giesecke Electronics Engineer, 23 years of experience in industrial and automotive HW and SW R&D. Supporting Arduino open-source community since 2014.

Updated October 23, 2024 04:29