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MAKE-ing with LabVIEW - Part Three

MAKE-ing with LabVIEW & Raspberry Pi: Part 3 – Raspberry Pi Setup

In Part 3 of this series on using the Raspberry Pi with LabVIEW I will be configuring a Pi 3 B and installing the LINX Toolkit on it. I will also cover some handy hints & tips when setting up the Raspberry Pi.

Introduction

This guide is based on the official set up guide from the Raspberry Pi foundation – found here.

We’ll be setting up the Pi with the latest Raspbian OS package downloaded from the official Pi website and then installing the LabVIEW Run-time.

The Raspberry Pi website offers Raspbian and NOOBS – NOOBS is an easy way to download and try out different OSes for it but it takes up more space on your SD card and may prevent things like configuring it to run headlessly (without a display). I also expect that only Raspbian is supported by the LINX Toolkit.

Prerequisites:

For the initial setup, you’re going to need the following:

Equipment required to configure a Raspberry Pi.
Time to gather your tools to harvest the Raspberry Pi!
  • Raspberry Pi: The LINX Toolkit officially supports the Pi 2/3 but I will provide an update or a separate post on other targets such as the new Pi 4 and the Pi Zero W.
  • Power Supply: For the Pi 2/3 you need a MicroUSB with an output of at least 2.5A and 3.0A USB-C for the Pi 4.
  • >=8GB microSD card: You can use a blank/formatted card or you can buy microSD cards with NOOBS (the Raspberry Pi OS launcher) preinstalled. The SD card will be the disk drive of your Raspberry Pi so will contain the OS and all of your programs/files – it’s worth getting a decent Class 10 SD card or above.
  • SD Card Reader: You’ll need to format & install the OS image using another computer with an SD card reader. You might also need a microSD to SD adapter.
  • Screen and Keyboard/Mouse: Recommended for the initial setup but read the hints & tips at the bottom of the post to learn how you can set up the Raspberry Pi without these and use SSH and/or VNC to access the Pi remotely.
  • Ethernet Cable / WiFi Credentials: To install the LINX Toolkit / LabVIEW Runtime to the Raspberry Pi it will need to be connected to the internet (to download the LabVIEW Runtime) and be on the same network as your LabVIEW 2019 installation (to configure/setup the Raspberry Pi and to deploy code to it).

Of course, you’ll also need your laptop/PC with LabVIEW 2019 and the LINX Toolkit installed – as discussed in Part 2.

How to: Set up a Raspberry Pi for LabVIEW

  1. Download the Raspbian OS

    Go to the download page for the Raspbian OS and download the latest Desktop edition (at the time of writing that is Raspbian Buster). There are three editions of the OS available:
    Desktop: The main OS installation that includes a GUI desktop. The GUI can be turned off to improve performance later.
    Desktop and recommended software: As per the ‘Desktop’ download but includes additional preinstalled applications (e.g. for education/programming purposes) – find out more about what’s included here.
    Lite: This is a minimal OS installation without any desktop functionality – you have to use the command-line interface. You can install the desktop support later if you want.Raspbian Download Options

  2. Install the OS to the microSD card

    The easiest way to prepare the SD card for your Raspberry Pi is to use balenaEtcher – a multi-platform GUI tool that can format and install the Raspbian OS image to the SD card. Alternatively you can use Win32DiskImager. Note that this will format/wipe the SD card.
    – Download and install balenaEtcher from here. It will automatically open.
    – Select the Raspbian OS image file you downloaded in the previous step (you don’t need to extract the .zip file).
    – Select the correct drive for your SD card.
    – Click ‘Flash!’ to begin. The process will take around 5-10 minutes.
    The instructions for writing the image to the SD card can also be found here.Install OS image using balenaEtcher

  3. Connect your Raspberry Pi

    Now you have your SD card prepared, you can install it and connect everything up.
    – Install your SD card to the underside of the Raspberry Pi
    – Connect your mouse/keyboard to the USB ports
    – Connect your display(s) to the HDMI port(s)
    – (Optional) Connect an ethernet cable from your Raspberry Pi to your network / router

  4. Turn on the Raspberry Pi

    Connect the power supply to the Raspberry Pi. You should see a red LED on the Raspberry Pi board and after a few moments you should see raspberries on the display and the Raspberry Pi will boot to the desktop.

  5. Configure the OS

    When it has finished booting, a wizard will appear to allow you configure the basic settings on the Raspberry Pi like the language, timezone and WiFi settings (if present).
    – Firstly, enter your country, language and timezone.
    – On the second screen you can enter a new password for the ‘pi’ user account and make a note of it – you’ll need it.
    – Thirdly, if your Pi has onboard WiFi (e.g. a Pi 3, 4 or Zero W) then you can connect to it now
    – Lastly you can check for updates to the OS and applications. The wizard will then prompt you to reboot the Pi if required.
    Raspberry Pi Setup Wizard

  6. Hooray!

    If you made it this far – congratulations, you now have fully functioning Raspberry Pi computer!

    If you ran into any issues – check out the official troubleshooting guide or the Raspberry Pi help forums.

  7. Enable SSH

    SSH allows you to remotely access a command-line prompt on the Raspberry Pi. This allows you to enter linux commands to access/control the Raspberry Pi. It’s also required by the LINX Toolkit to install the LabVIEW run-time and deploy projects to the Pi.

    In newer versions of Raspbian it is disabled by default (to protect against hackers).

    Open the Raspberry Pi Configuration utility from the ‘Preferences’ menu, open the ‘Interfaces’ tab, click ‘Enable’ next to SSH and then click OK.

  8. (Optional) Enable GPIO Hardware Peripherals (SPI/I2C/Serial)

    The GPIO pins on the Raspberry Pi support a number of protocols/interfaces but they need to be enabled so they can be used from the LINX Toolkit. You can enable these peripherals from the Raspberry Pi Configuration screen as shown above.

    If enabling the Serial Port interface, make sure that Serial Console is disabled so that the port is accessible in LabVIEW.

    At the time of writing, the LINX Toolkit supports I2C on pins 3&5, Serial on pins 8&10 and SPI on pins 19,21&23. See the pinout here for more information.

    Note: All of the GPIO pins are 3.3V – directly connecting any signal >3.3V will likely damage the GPIO functionality of the Raspberry Pi.

  9. Install the LINX Toolkit / LabVIEW Run-time (Method 1: Wizard)

    Note: The first beta version of the LINX Toolkit had a number of bugs that mean the installation fails – either apply the fixes at the bottom of the post first and come back here or try the Manual method below.

    Update 10/10/2019: NI have updated the LINX Toolkit to Beta 2 which fixes using the Wizard to deploy the LabVIEW Run-time to the Raspberry Pi and adds official support for the Raspberry Pi 4. I have updated the article reflect this.

    – Open the Target Configuration Wizard from ‘Tools -> MakerHub -> LINX -> LINX Target Configuration…”

    – Enter the hostname/IP, username and password for the Raspberry Pi and click ‘Connect’

    – Click the ‘Install Software’ button and then click ‘Install’ – this will perform the required configuration on the Raspberry Pi and install the LabVIEW run-time. This will take a few minutes.


    After the installation is complete, the ‘Installed Version’ should show something like 19.X.X (for me at the time of writing it is 19.0.1-2).

  10. Install the LINX Toolkit / LabVIEW Run-time (Method 2: Manual)

    The manual installation method is to use a terminal or SSH session on the Raspberry Pi and run the following commands:
    echo "deb [trusted=yes] http://feeds.labviewmakerhub.com/debian/ binary/" | sudo tee -a /etc/apt/sources.list
    sudo apt-get update
    sudo apt-get install lvrt19-schroot -y


    The first line you only need to run once to set up the LINX Toolkit repository on the Raspberry Pi. The 2nd and 3rd lines retrieve the latest package versions from the repository and then install the ‘lvrt19-schroot’ package which has the LabVIEW Run-time.

  11. Run the Example Project

    If everything has gone smoothly so far you should now have the LabVIEW Run-Time installed on your Raspberry Pi.

    You can test it out by pressing the ‘Launch Example’ button from the Wizard which will generate a example project and configure the IP address of your Pi for you.

    If the ‘Launch Example’ button doesn’t work, you can copy the template project from C:\Program Files (x86)\National Instruments\LabVIEW 2019\vi.lib\MakerHub\LINX\Private\Templates\Raspberry Pi 2 B to another folder, open the project and change the IP address to match your Pi and then run it. To do this, right click on the Raspberry Pi target in the project and go to ‘Properties’, then update the IP Address field and click OK.

    You can then ‘Run’ the VI, the code will be deployed to the Raspberry Pi and if you have an LED to hand you should be able to toggle it by connecting it to the correct GPIO pin.

  12. Congratulations!

    That’s it! You’ve now configured a new/blank Raspberry Pi with the latest Raspbian OS image, configured it for remote access, installed the LINX LabVIEW Run-time and run the sample/template project.

Hints & Tips

Remote Access – VNC

Once you have done the initial setup of the Pi and it is connected to your network, you might not want to keep a display/mouse/keyboard attached to it. The solution is to enable VNC – it’s the Raspberry Pi equivalent to remote desktop and allows you to view and control the Raspberry Pi remotely.

The first step is to enable the VNC server on the Raspberry Pi using the configuration tool (or via sudo raspi-config). You will then need to install the VNC Viewer which you can download from here.

Once installed, you can enter the hostname/IP address of your Raspberry Pi and then connect using the same username/password as SSH.

Accessing the Raspberry Pi via VNC

Headless Raspberry Pi (no display)

If you don’t have a mouse/keyboard/screen available for the initial setup, you can still setup and configure your Pi over the network.

You can do this by modifying the contents of the ‘boot’ partition of the SD Card on your computer after you have written the Raspbian OS image to it.

WiFi

If you need to use the Pi over WiFi, you can confgure the WiFi credentials by creating a file called wpa_supplicant.conf in the ‘boot’ partition of the SD card. Its contents will then be copied over to the Raspberry Pi when it boots up.

The file needs to look like this:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=«your_ISO-3166-1_two-letter_country_code»

network={
    ssid="«your_SSID»"
    psk="«your_PSK»"
    key_mgmt=WPA-PSK
}

You will need to fill in the country code, SSID and pre-shared key. Ensure that the file has Linux line endings (LF or ‘\n’ instead of CRLF ‘\r\n’).

SSH

Create/copy a file called ‘ssh.txt’ (case-sensitive) onto the ‘boot’ partition of the SSD card. The contents of the file doesn’t matter.

Enabling SSH on the Raspberry Pi via the SD Card
Enabling SSH via the SD card boot partition

Other Configuration Options

After setting up the WiFi and enabling SSH, you should be able to boot up and then SSH into the Pi. You can try connecting to the default hostname ‘raspberrypi’ or check your router/network settings to find its IP address.

Once you have connected via SSH, you can run sudo raspi-config to access a terminal-based configuration editor which allows you to change all of the settings of the Pi as per the initial setup etc.

Raspberry Pi terminal configuration utility.
Raspberry Pi Configuration from the terminal (looks pretty oldschool!)

Controlling the LabVIEW Run-time

The LabVIEW Run-time runs as a service on the Pi, to start/stop/restart it you can use the following terminal commands:

sudo systemctl [stop|start|restart] labview.service

This can be useful in case you want to ‘reboot’ LabVIEW without restarting the Pi. Note that this will abort any currently running LabVIEW VIs that are running on the target.

Fixing the LINX Toolkit Beta

Update 10/10/2019: The LINX Toolkit has now been updated to Beta 2 on the NI Software Technology Preview – the fixes below are no longer necessary to install the LabVIEW Run-time to the Raspberry Pi. This update potentially breaks the ability to create Real-Time Applications (rtexe) in LabVIEW 2019 – performing a repair on LabVIEW Real-Time from NI Package Manager fixed this for me.

At the time of writing the LINX Toolkit Beta is just a copy of the 2014 version of the Toolkit. It has not been updated or fixed to work with LabVIEW 2019 and newer Pi Targets.

Fortunately I have been able to resolve most of the issues to get the Wizard working to install the Toolkit and launch the examples. This requires changes to some of the VIs to update it for the new LabVIEW Run-time for the Pi.

Most of the VIs are located in C:\Program Files (x86)\National Instruments\LabVIEW 2019\vi.lib\MakerHub\LINX\

Remove LabVIEW 2014 Prompt

Open LMH-Linx.lvlib:System Check.vi and change the string in the case structure from “2014” to “2019”. This will remove the dialog that appears when opening the dialog that you’re using the wrong version of LabVIEW.

Remove LabVIEW 2014 check from LINX Toolkit
Remove LabVIEW 2014 prompt from LINX Toolkit in System Check.vi

Update for 2019 LabVIEW Run-time

Open LMH-LINX.lvlib:Install LV Support.vi and change the package name to ‘lvrt19-schroot’:

Updates to the Install LV Support VI.
Update the ‘Install LV Support’ VI

Open LMH-LINX.lvlib:Add MakerHub Feed.vi and modify as follows:

Updates to the Add MakerHub Feed VI.
Update the ‘Add MakerHub Feed’ VI

Open LMH-LINX.lvlib:Check Target LV Package Version.vi and change the package name to ‘lvrt19-schroot’:

Modifications to the Check Target LV p
Package Version VI.
Update the ‘Check Target LV Package Version’ VI

Note: It will still show the latest version as the LV2014 version but it doesn’t affect the installation

Add Raspberry Pi 3 (& 4?) Support

The library detects the target type according to the CPU name retrieved from the cat /proc/cpuinfo command. This is different for the Raspberry Pi 3 (and also the Pi 4 and maybe the Pi Zero etc.).

To add support in the Wizard for new targets we need to do the following:

  1. Determine the CPU type on the Raspberry Pi by running cat /proc/cpuinfo in a terminal or via SSH. At the end of the output it will show a line saying something like Hardware: BCM2835. This is the CPU type used by the LINX Toolkit wizard.
  2. Open LMH-LINX.lvlib:Get Device Type.vi and add a new entry for the Raspberry Pi you are using (e.g. 3/4):
  3. To fix the ‘Launch Example’ button in the Wizard, we also need to modify it to use the Raspberry Pi 2 B example files. Open LMH-LINX.lvlib:Script Example Project.vi and modify as follows:

If you want to look into the LINX Target Configuration VI, you can open it from the Tools menu and then press ‘Ctrl+.’ to abort the VI. You can then look through its block diagram. Be aware that any changes you make might be overwritten by a new version of the Toolkit. Feel free to leave a comment if you’ve made any other useful changes!

Conclusion

This has been quite a long post, but we’ve now covered everything required to setup a Pi for use with LabVIEW. I’ve also provided fixes for the current Beta version of the LINX Toolkit so you can use the Wizard to install the LabVIEW Run-time and provided some hints & tips for remotely accessing the Raspberry Pi and for setting up the Pi without a mouse/keyboard/screen attached.

In the next post, I’ll go into some details about some of the on-board communications methods on the Raspberry Pi. I will cover network communications and serial ports. Tune in next time!

MAKE-ing with LabVIEW & Raspberry Pi: Part 2 – Installing the LINX Toolkit

In Part 2 of this series on using the Raspberry Pi with LabVIEW, I’ll be looking at installing the latest beta of the LINX Toolkit with LabVIEW 2019. In Part 1 I introduced the series, some of the reasons why you might want to use a Raspberry Pi with LabVIEW and I introduced the Storm Monitor project I’m going to be working towards over the course of the series.

Prerequisites:

For the majority of this series I will be using a Raspberry Pi 3 Model B+. I’ll also be using LabVIEW 2019 so you’ll need to have that installed. You’ll either need to have purchased LabVIEW, be using an evaluation version or wait for the free LabVIEW Community Edition. I’ll be using the latest beta version of the LINX Toolkit (as of 26/09/2019).

LINX Toolkit for LabVIEW

The LINX Toolkit is a free LabVIEW Addon (made by NI’s MakerHub) that allows you to write LabVIEW code on the Raspberry Pi. It also allows you to use an Arduino as an IO device with LabVIEW. You can’t write LabVIEW code that runs directly on the Arduino (take a look at the TSXperts Arduino Compiler).

With the LINX Toolkit you can add the Raspberry Pi as an additional target in a LabVIEW project. You can then download/deploy that code to the Raspberry Pi.

Until recently, the toolkit was only supported on LabVIEW 2014 but part of the LabVIEW Community Edition announcement was that NI would be updating the toolkit to work with LabVIEW 2019 onwards. A beta of the new version for LabVIEW 2019 is through the NI Software Technology Preview.

Note: Since this is beta software, it may be unstable (it is definitely buggy since it’s just a re-packaged version of the library for LabVIEW 2014) and may cause crashes. I don’t recommend installing it on your main development PC – you have been warned!

How to Install the LINX Toolkit

  1. Apply to the NI Software Technology Preview

    Apply here. It may take some time for your application to be approved but once you have been accepted, you will have access to the NI Software Technology Preview Community which gives you access to pre-release versions of NI Software, including the LINX Toolkit.

  2. Find and Download the Toolkit

    Once you have access, go to the LINX Toolkit Discussion (link) on the Software Technology Preview Community and download it from the ‘LabVIEW 2019 LINX Toolkit Beta Download’ thread.

  3. Install it!

    The download is a .iso disk image file which you can mount in a virtual CD-drive by right clicking on the file and selecting ‘Mount’ or by double-clicking on it. You can then install the toolkit by opening the ‘LVLINX2019’ drive and double clicking ‘Install’. This will install the toolkit using the NI Package Manager. Follow the instructions in NI Package Manager to install the toolkit – it should only take a few minutes.

  4. That’s it!

    After NI Package Manager does its thing, you’ll then be able to launch LabVIEW and access the LINX Toolkit from the LabVIEW Tools Menu:

Conclusion

In this short post (because I cannot add multiple how-to’s) I have covered how you can setup and install the beta of LINX Toolkit for LabVIEW 2019 using NI Package Manager (NIPM). I will update the post as new updates to the LINX Toolkit are released by National Instruments.

In the next post I’ll be setting up/configuring the Raspberry Pi for use with LabVIEW and offering some hints & tips for using it.

MAKE-ing with LabVIEW & Raspberry Pi: Part 1 – Introduction

This is the first part in a series about using the Raspberry Pi with LabVIEW and the LINX Toolkit. It follows the announcement of the release of the free LabVIEW Community Edition from National Instruments.

Introduction

I recently posted about the big news from National Instruments that they would be releasing a free LabVIEW Community Edition in 2020 with a beta/preview version available later this year.

Of course, as an NI Alliance partner I use LabVIEW professionally on a daily basis so LabVIEW being free for non-commercial use doesn’t really affect me but the updates to the LINX Toolkit are very interesting – namely that it can now be used in commercial applications. Of course, making LabVIEW free will help to grow its adoption as a language which is definitely a good thing.

To celebrate this announcement, over the coming weeks and months (as I find the time) I am going to be posting a series of articles about using the LINX Toolkit with the Raspberry Pi in LabVIEW.

Over the years I have built up a pretty extensive collection of Raspberry Pis and various bits of useful hardware to that allow a Raspberry Pi to interact with the outside world as you might using LabVIEW and DAQmx/cRIO etc. The goal of these articles is to help you get started with the Raspberry Pi and LabVIEW and to show you some of the things you can do with it.

Raspberry Pi 4 Promo
The Raspberry Pi 4 was launched in June 2019.

An extra bonus to this is the recent launch of the Raspberry Pi 4 – the latest Raspberry Pi board with a more powerful processor (1.5GHz quad core, 1/2/4GB of RAM, USB 3, onboard Wifi/Bluetooth and Gigabit Ethernet. Although not officially supported by the LINX Toolkit yet, I’ll be having a go at getting it up and running with LabVIEW.

MAKE-ing with LabVIEW & Raspberry Pi – Series Topics

I haven’t fully planned out each article but over the course of the series I’d like to cover the following:

  • Getting Started with the LINX Toolkit, Raspberry Pi and LabVIEW
    • Installation & Configuring the Raspberry Pi
    • Building and deploying your first application
    • Raspberry Pi 4
  • On-board communications
    • Networking (TCP/IP over Ethernet/WiFi)
    • Serial / RS-232
  • Data Acquisition / Interacting with the real world
    • Analog I/O
    • Digital I/O
    • Other Sensors
  • User Interface / Display Options
    • Nextion Touch Screen
    • LabVIEW NXG Web Module (which will also be available for free with the Community Edition)
    • Configuring the Raspberry Pi to run a web-page in Kiosk mode
Raspberry Pi hardware and sensors.
Some of the Raspberry Pi hardware we’ll be using over this series of articles

That covers the basics (and there’s a lot there already!) but some other topics I could cover include GSM/GPS. the Pi Zero, using an Arduino as an additional I/O device, Bluetooth communications etc. – please leave a comment if there’s something you’d like me to cover and I’ll try to include it in a future article.

Prerequisite LabVIEW Knowledge?

For this series I’m going to be assuming that you are already fairly familiar with LabVIEW but that are maybe new to the LINX Toolkit and using it with a Raspberry Pi. If you’re new to LabVIEW (maybe you’re checking out the free Community Edition – great, welcome!) then I would suggest starting here or here to learn some of the basics first.

Why use a Raspberry Pi?

The main reason for using a Raspberry Pi is that it is a low-cost and small form-factor computer with plenty of GPIO pins increasing its hardware capability. As an open-source platform, there are 100s of sensors, hats (addon boards), cases and display options available.

Some commercial applications that might be suited to a Raspberry Pi could be:

  • Low-cost low-channel count data acquisition system (e.g. monitoring a handful of analog inputs where timing/accuracy aren’t critical)
  • Headless monitoring system (to monitor a system and report data to the cloud)
  • Low-cost HMI / display module (instead of using a PC alongside a CompactRIO, for example)

Of course, while a Raspberry Pi can be a neat low-cost solution for a headless data acquisition system, it definitely doesn’t replace NI’s other platforms like the sbRIO/CompactRIO or PXI. These systems still have their place as they offer things like:

  • Deterministic control applications with LabVIEW Real-Time and high-speed control/processing with LabVIEW FPGA
  • CompactRIO C-Series modules and PXI cards offer a much wider range of input/output options and much higher measurement specifications (e.g. ranges, resolution, accuracy, channel counts etc.)
  • CompactRIO is a robust/rugged platform that can operate in industrial environments

For this series of articles, I’m going to be exploring the Raspberry Pi’s capabilities through my own hobby project – a storm/weather monitoring station.

Application: Raspberry Pi Storm Station

Most of the time when I’m learning new technologies, I like to have an application in mind as it gives me something to work towards. For this Series, I’m going to be looking at building a Storm Watcher / Weather Station. This is very much a hobby project but it will demonstrate a number of capabilities

Here’s a rough idea of what I want it to be able to do:

  • Temperature, Pressure & Humidity Measurements
  • Lightning Detection (using one of these)
  • On-board display of measurements
  • The ability to push measurement data to the cloud
  • Retrieve current/forecast weather information
An exploded view of a Raspberry Pi with a touchscreen display case.
Raspberry Pi case with a 3.5″ Touchscreen

Why? My mum is a keen weather watcher and often uses websites like this one to see where there are storms etc. – I thought it would be a nice little project so she can start detecting her own storms. The Raspberry Pi is ideal for this as it’s a low-cost piece of hardware with built-in WiFi and there are lots of options for small displays etc.

Up Next: Part 2

Stay tuned for Part 2 where we’ll get started with installing and configuring the necessary software on our PCs. For this we’ll be using LabVIEW 2019 and the latest beta version of the LINX Toolkit.

Free LabVIEW™ for everyone – LabVIEW Community Edition coming soon!

One of the most newsworthy aspects of GDevCon#2 was a very special announcement from National Instruments that they would be releasing the LabVIEW Community Edition – a free version of LabVIEW™ Professional for non-commercial use.

Yes, that’s right…

You will be able to download and use LabVIEW™ for FREE!

Read more