Section 1: IoT

The IoT sample demonstrates an IoT device that connects to WiFi and Golioth, then sends data, logs, and reacts to remote-procedure calls. Using this sample code you will learn about:

• Building and flashing applications in Zephyr
• Adding persistent credentials using the serial shell

• Get to know the Golioth web console:

  • Time-series and stateful data reported to the cloud
  • Adjusting device settings using the cloud-side Settings service
  • Receiving remote logging information from the device
  • Using remote procedure call (RPC) to return current WiFi connection info

Hardware

This demonstrates how to interact with the Golioth Cloud using Zephyr on any of the following boards:

• Nordic nRF7002 Development Kit.
• Nordic nRF9160 Development Kit.

Build Instructions

Prerequisites

Follow the README in the root of this repository to install a virtual environment and use west init/west update to clone all dependencies. Remember to restart your virtual environment when beginning a new terminal session.

Build project

From the root directory of this repository, build using the following command:

$ # Building for nRF7002dk
$ (.venv) west build -b nrf7002dk/nrf5340/cpuapp 01_IOT

$ # Building for nRF9160dk
$ (.venv) west build -b nrf9160dk/nrf9160/ns 01_IOT

Flash project

Connect your computer to the board via USB. (On the nRF7002dk, do not use the USB port labelled nRF USB.) Run the following command:

$ (.venv) west flash

Add credentials

Use a serial terminal program to connect to the device using 115200 8N1 as the settings.

nRF7002dk

• Use the highest numbered port
• Use the following syntax to store your WiFi and Golioth credentials on the device:

uart:~$ settings set wifi/ssid <my-wifi-ap-ssid>
uart:~$ settings set wifi/psk <my-wifi-ap-password>
uart:~$ settings set golioth/psk-id <my-psk-id@my-project>
uart:~$ settings set golioth/psk <my-psk>
uart:~$ kernel reboot cold

nRF9160dk

• Use the lowest numbered port
• Use the following syntax to store your Golioth credentials on the device:

uart:~$ settings set golioth/psk-id <my-psk-id@my-project>
uart:~$ settings set golioth/psk <my-psk>
uart:~$ kernel reboot cold

Application Behavior

When the app begins running it will connect to WiFi, then connect to Golioth and begin streaming simulated temperature sensor data:

*** Booting nRF Connect SDK v2.5.2 ***
[00:00:00.472,961] <inf> fs_nvs: 2 Sectors of 4096 bytes
[00:00:00.472,961] <inf> fs_nvs: alloc wra: 0, f90
[00:00:00.472,991] <inf> fs_nvs: data wra: 0, 154
[00:00:00.473,602] <dbg> golioth_iot: main: Start Golioth IoT
[00:00:00.473,663] <inf> golioth_samples: Bringing up network interface
[00:00:00.473,663] <inf> golioth_samples: Waiting to obtain IP address
[00:00:02.681,610] <inf> lte_monitor: Network: Searching
[00:00:04.387,664] <inf> lte_monitor: Network: Registered (roaming)
[00:00:04.388,763] <inf> golioth_mbox: Mbox created, bufsize: 1232, num_items: 10, item_size: 112
[00:00:06.575,164] <inf> golioth_coap_client_zephyr: Golioth CoAP client connected
[00:00:06.575,683] <inf> golioth_iot: Hello Golioth! 0
[00:00:06.575,714] <inf> golioth_iot: Streaming Temperature to Golioth: 27.270000
[00:00:06.575,897] <inf> golioth_iot: Golioth client connected
[00:00:06.575,927] <inf> golioth_coap_client_zephyr: Entering CoAP I/O loop
[00:00:07.245,117] <inf> golioth_rpc: RPC observation established
[00:00:07.339,355] <dbg> golioth_iot: temperature_push_handler: Temperature successfully pushed
[00:00:11.575,927] <inf> golioth_iot: Hello Golioth! 1
[00:00:11.575,988] <inf> golioth_iot: Streaming Temperature to Golioth: 27.730000
[00:00:12.716,247] <dbg> golioth_iot: temperature_push_handler: Temperature successfully pushed
[00:00:16.576,202] <inf> golioth_iot: Hello Golioth! 2
[00:00:16.576,263] <inf> golioth_iot: Streaming Temperature to Golioth: 27.930000
[00:00:17.281,219] <dbg> golioth_iot: temperature_push_handler: Temperature successfully pushed

Button and LEDs

One LED will always be blinking. Pressing the user buttons will change which LED is currently blinking

Time-Series and Stateful Data

Simulated temperature readings will be sent periodically to Golioth. Each of these readings is recorded with a timestamp when it was received.

When the user buttons are pressed to change which LED is blinking, the name of the currently blinking LED (LED or LED2) will be recorded on the Golioth LightDB State service.

Sensor Reading and LED Blinking Frequency

The Golioth Settings Service determines the frequency at which simulated temperature readings are sent and the frequency at which the LED blinks. The following keys are used for these settings:

• Sensor frequency (seconds): LOOP_DELAY_S
• Blink frequency (milliseconds): BLINK_DELAY_MS

Reporting Network Connection Information

A remote procedure call can be used to return information about the network to which the device is currently connected:

• get_network_info