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DC Power Monitor - nRF9160 DK Follow-Along Guide

This follow-along guide shows how to build your own DC Power Monitor using widely available off-the-shelf development boards from our partners. We call this Follow-Along Hardware, and we think it's one of the quickest and easiest ways to get started building an IoT proof-of-concept with Golioth.

You will learn how to assemble the hardware, flash a pre-built firmware image onto the device, and connect to the Golioth cloud in minutes. The follow-along hardware runs the same open-source firmware as the custom Golioth hardware described in the project page, and we provide instructions on how to build it yourself if you want to make changes for your specific application.

Build the hardware

The follow-along hardware is based on the Nordic nRF9160 DK cellular IoT development board for LTE-M & NB-IoT. We use an Arduino UNO click shield to add two mikroBUS™ host sockets to the nRF9160 DK board.

The mikroBUS sockets are populated with two of the same off-the-shelf MikroE Click sensor boards:

  1. VCP Monitor Click board with a Texas Instruments INA260 precision current/voltage/power monitor.

Device Photos

Hardware Block Diagram

Parts List

To assemble the follow-along hardware, you will need to purchase the following parts:

QuantityManufacturer Part NumberDigiKey Part NumberDescription
1NRF9160-DKNRF9160-DK-NDNordic nRF9160 DK Cellular IoT development kit
1GL1-1001887-GL1-100-NDHologram Hyper eUICC IoT SIM Card
1MIKROE-15811471-1341-NDMikroE Arduino UNO click shield adapter board
1MIKROE-19781471-1487-NDMikroE Weather Click sensor board
1MIKROE-13701471-1080-NDMikroE Relay Click sensor board
135951528-2395-NDAdafruit proximity, lights, gesture sensor)

Assembly Instructions

Step 1 - Install SIM card

With the board powered off, insert the SIM card into the socket and make sure the "SIM select" switch (SW7) is set to "SIM".

About SIM and eSIM

For more information about how to use this switch to select between the SIM card socket and the Embedded SIM (eSIM), see the Nordic SIM and eSIM documentation.

Step 2 - Set VDD IO voltage

Set switch SW9 (located next to the power switch) to 3V to set the VDD IO voltage to +3V.

About VDD IO

For more information about how to use this switch to set the VDD supply rail, see the Nordic VDD supply rail documentation.

Step 3 - Install Arduino UNO click shield

Install the Arduino UNO click shield into the nRF9160 DK Arduino UNO header socket.

Step 4 - Install Click sensor boards

  1. Install a VCP Monitor Click board into the mikroBUS host socket labeled "1".
  2. Install a VCP Monitor Click board into the mikroBUS host socket labeled "2".
You must move a resistor on one of the click boards

The VCP Monitor Click boards have resistors that set the i2c address. To use more than one on the same bus, move one of the resistors. In this case, the board in slot 2 was altered by desoldering the 0-ohm resistor connecting A0<->GND and resoldering it to connect A0<->VCC.

Flash the firmware

The firmware source code and pre-built firmware images for this reference design are available on GitHub under a permissive Apache-2.0 license.

note

The DC Power Monitor firmware is based on the Golioth Reference Design Template. Changes from the upstream template are periodically pulled into new releases of this firmware. Check out the firmware CHANGELOG for a detailed list of changes included in each release.

Flash the pre-built firmware image

tip

We recommend getting started by flashing the latest pre-built release firmware image. These release images have been tested by the Golioth team and are the quickest way to verify that the hardware is working correctly.

Step 1 - Download the pre-built firmware image

Download the latest dcpower_vX.X.X_nrf9160dk_full.hex firmware image file from:

GitHub Releases
DC Power Monitor

Step 2 - Install nRF Connect for Desktop

We recommend using the nRF Connect for Desktop application to flash the pre-built firmware image to the board.

You can download the latest version for Windows, Mac, and Linux from the Nordic website (make sure to choose your operating system from the dropdown):

Nordic Semiconductor
nRF Connect for Desktop

Step 3 - Flash firmware with the Programmer app

After installing nRF Connect for Desktop, open the Programmer app:

Click on "Select Device" to show the list of available boards:

Select the board used in your follow-along hardware:

Drag & Drop the dcpower_vX.X.X_nrf9160dk_full.hex file onto the "File memory layout" pane:

Click "Erase & Write" to program the firmware image into the device:

Step 4 - Verify firmware with the Serial Terminal app

If the firmware was programmed successfully, you can verify the firmware version printed on the serial terminal.

Open the nRF Connect for Desktop Serial Terminal app:

Click on "Select Device" to show the list of available boards:

Select the board used in your follow-along hardware:

Click "Connect to port":

You should see the firmware version printed in the log output (if you connected after the log message was printed, press the RESET button on the board):

Connect to Golioth

In this section you will learn how to connect the follow-along hardware to the Golioth Cloud.

Register & Log In

The Golioth Console provides a web-based dashboard for registering & managing your devices.

To get started, log in to the Golioth Console. If you have not already signed up for a Golioth account, choose "Sign Up" to register for a new account first.

Register the Device

The Quick Start Wizard will guide you through the process of creating your first Project and registering your first device.

Launch the Wizard by clicking on the "Quick Start" button in the top right of the console window.

You may have already created a project

If you previously registered for Golioth, you may have already created a project and registered a device the first time you used the Quick Start Wizard. Feel free to skip this section and register a new device in your existing project instead of creating a new project via the Quick Start Wizard.

Step 1 - Create a Project

All devices must belong to a Project. Before you can register the device you must create a Project in the Golioth Console.

Step 2 - Register a Device

Choose a name for the device or use the randomly generated one.

Step 3 - Setup your Device

The Quick Start Wizard will automatically generate pre-shared key credentials for the device that was just registered.

How to find device credentials

After you click "Close" in the Quick Start Wizard, you can always find these credentials again on the device's "Credentials" tab.

Provision the Device

Now that the device is registered in the Golioth Console, the device hardware needs to be provisioned with the pre-shared key that was generated in the previous step.

In the nRF Connect for Desktop Serial Terminal (or your preferred serial terminal application), set the following values using the device shell:

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

For example, setting the golioth/psk-id should look like this:

After clicking the "Send" button, you should see the command output showing that the PSK-ID was saved to the device's non-volatile storage:

Verify the Device Connection

Once the device has rebooted, the firmware should automatically connect to the Golioth Cloud.

Once the device has connected, you should see the device "Connection Status" change to "online".

If you click on the device's "LightDB Stream" tab, you should see data streaming in from the device.

You made it!

Congratulations, you have successfully connected your follow-along hardware to the Golioth Cloud!

Next Steps

Explore the Golioth Console

Now that your device is connected to the Golioth Cloud, you can explore the other features of the Golioth Console.

Some ideas:

  • Check out the "Logs" tab to see real-time log messages streaming from the device.
  • Navigate to the "Remote Procedure Call" tab and call the get_network_info method to query and return detailed information about the device's network connection.

Try the Command Line Tools

In addition to using the web-based Console, it is also possible to provision and manage devices using the Golioth Command Line Tools.

Try logging into your account via the command line tools and list the devices in your project with the command:

goliothctl device list

Compile a custom firmware image

The source code for the pre-built firmware image can be customized for your specific application. For detailed instructions on how to build the reference design firmware used in this guide, see the README in the firmware GitHub repo.

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