This application implements a basic wireless sensor. The application reads the sensor and uses NORA-B1 Bluetooth to broadcast the sensor measurements. It does that by apending the measurement data to Bluetooth LE Manufacturer-specific Advertising Data.
So the device broadcasts the measurements, and any Bluetooth device that performs a scan operation within range, can get these data without the need for a specific connection.
This is the starting point, to read and broadcast the measurements, so that a Gateway can receive those measurements and send them to the MQTT Broker.
One way to implement this sensor Bluetooth LE broadcaster is to use an XPLR-IOT-1 device and a MikroE HVAC Click board MIKROE-4290 which contains a Sensirion SCD41 CO2 sensor.
You can connect the sensor to the Qwiic connector of the XPLR-IOT-1 device.
Another option is to use a MINI-NORA-B1 Evaluation kit and connect the MikroE HVAC Click board MIKROE-4290 to mikroBUS slot 1.
If you decide to use Hardware setup option 2, change the uart rx/tx pins as indicated by the comments in nrf5340dk_nrf5340_cpuapp.overlay file.
The example is build using nRF Connect SDK version 1.9.1 and is advised to use this version to build the Sensor Bluetooth LE Broadcaster.
You can build the application as any other Zephyr project (you can get some help here).
This application is set up to compile and create an image that needs a J-Link to be programmed in MINI-NORA-B1 or XPLR-IOT-1. The option to compile it as an updateable image for use with a bootloader is not implemented.
Important Note:
- If you intend to use Hardware setup option 1, leave the project as is and just build it.
- If you intend to use Hardware setup option 2, change the uart rx/tx pins as indicated by the comments in nrf5340dk_nrf5340_cpuapp.overlay file.
binaries folder contain pre-compiled images, if you do not want to build the project.
Known Issue During building you may see some warning messages. These are harmless for this application. They are produced by the driver of SCD41 which is used as an out-of-tree module to the Zephyr project (driver source can be found here).
You can flash the project as any other Zephyr project (using VS Code is recommended). A J-Link is required to Flash the application. You can get some help on Flashing here.
This application uses both the APPLICATION and NETWORK cores of nRF5340 in NORA-B1.
If do not want to build the application, you can use the pre-compiled images and programming scripts in binaries folder
If you want to flash the project, after building:
- You can use VS Code to Flash the device (recommended)
- You can use
build/zephyr/merged_domains.hexfile to program the app with nRF Connect -> Programmer application. - You can use nrftools to program the device with command line. You can use
build/zephyr/zephyr.hexandbuild\hci_rpmsg\zephyr\zephyr.hexfiles for this.
The sensor driver gives some options but leaving as is should work properly. You may want to check the temperature offset, and altitude (affects CO2 measurement) in nrf5340dk_nrf5340_cpuapp.overlay file.
The application itself does not contain a lot of configuration options, just the measurement period.
You can adjust the measurement period with the MEASUREMENT_PERIOD definition in main.c file.
You can also change the name under which the device advertises, but it is not advised (should change the name in the Gateway code too, to be able to recognize it).
To change the name you can change the DEVICE_NAME definition in main.c file.
When running the application, at the uart console output you should see something like this
During initialization of broadcaster application, an error may appear in the initialization stage of the sensor (this is a driver issue), but this does not affect the functionality of the example or the sensor measurements.
The console outputs the measurements and each measurement's ID, and the hex data that are transmitted to Bluetooth LE Manufacturer-specific Advertising Data.
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