Author Archives: Gordon Hollingworth

Share your keyboard and mouse between computers with Barrier

via Raspberry Pi

Declutter your desk by sharing your mouse and keyboard across multiple computers at once, including your Raspberry Pis, with Barrier. Raspberry Pi Director of Software Engineering, Gordon Hollingworth, shows you how.

Barrier walkthrough

Subscribe to our YouTube channel: http://rpf.io/ytsub Help us reach a wider audience by translating our video content: http://rpf.io/yttranslate Buy a Raspbe…

Desk clutter is a given

My desk is a bit untidy. Talking to people in our office, you’ll find that it’s mostly because I only clear it properly once a year, or leave it entirely until the next time we move office!

It’s cluttered with Raspberry Pis of random types, with little tags saying what’s wrong or right about each one, and then there’s every manner of SD card, adapter, JTAG connector, headphones, and whiteboard marker pens you can dream of filling the gaps.

But one thing that really annoys me is that I tend to have a mouse and keyboard per computer, and I’ve got at least four computers running at my desk at any one time.

Solutions to this problem have existed for a very long time, known as KVM (keyboard, video and mouse) switches; many people use these to switch (literally with a big toggle switch) between computer 1, 2, and 3 while using a single screen.

But if that’s what you want to do, the best solution is to use VNC on each of the computers so you can use a single display, keyboard, and mouse to access each of their screens and bring them all together.

And, that’s okay, but…

But that’s not quite what I want: I like having the mass-screen real-estate around me, and I like just glancing to the left to see my Raspberry Pi on its own screen.

If only there was a way to share my mouse and keyboard across multiple computers without having to flick switches or unplug USBs.

Well…

Barrier to the rescue!

In the same way one may set up multiple monitors for one computer, and move the mouse cursor seamlessly between them, Barrier allows you to share peripherals between multiple computers, allowing you to host your keyboard and mouse on one computer. It lets you simply drag your cursor from screen to screen, from device to device, as if by magic.

Download and set up Barrier

Barrier is free to use, and simple to set up. You can either follow the video tutorial shared above, or continue reading below:

Download barrier to your main computer

First, download and install Barrier from the developers’ installation page: github.com/debauchee/barrier/releases

At the end of the installation, the application will run. Select the Server option (the server is the one that has the keyboard and mouse that you want to share).

Next select Configure Server. Click on the computer screen in the top-right and drag it to where you want it to appear in relation to the server. It will default to being called ‘Unnamed’.

Next, double-click the new ‘Unnamed’ screen to set it up.

The only thing you need to do here is to set the screen name. Here I’ve changed it to ‘raspberrypi’.  Click OK here and on the Server configuration‘ dialogue. You’ll return to the main Barrier page. Click Reload.

Download Barrier to your Raspberry Pi computer

Now turn to your Raspberry Pi, open a terminal window (Ctrl-Alt-T if you didn’t know), and run:

sudo apt install barrier

Once installation is complete, Barrier should appear in the Accessories drop-down menu, which you can access via the main menu icon (the Raspberry Pi logo in the top right-hand corner). Select Barrier and, this time, choose Client.

If you leave Auto config selected, Barrier should just work, as long as the screen name is correct (you can change this by clicking Barrier and then Change settings) and matches the name you told the server.

And there you have it. You can now use your mouse and keyboard across both your computers. And, if you have enough desktop space for even more monitors, you can continue to add devices to Barrier until your room ends up looking something like this:

A man standing in front of a wall made of computer screens

If you use Barrier to clean up your workspace, make sure to share a ‘before’ and ‘after’ photo with us on Twitter.

The post Share your keyboard and mouse between computers with Barrier appeared first on Raspberry Pi.

Introducing Raspberry Pi Imager, our new imaging utility

via Raspberry Pi

We’ve made a simpler way to image your microSD card with Raspbian, the official Raspberry Pi operating system, and other operating systems. Introducing our new imaging utility, Raspberry Pi Imager.

Raspberry Pi Imager

Simplifying the Raspberry Pi experience

For me, one of the most important aspects of the Raspberry Pi experience is trying to make it as easy as possible to get started.  To this end, since launching the first Raspberry Pi, we’ve added a GUI to our operating system, a wizard to help you set up your Raspberry Pi the first time you boot it, and lots of books and magazines to get people up and running.  We’ve even developed the Raspberry Pi Desktop Kit to put all the things you need (yes, Alex, I know – except for a monitor) into a single box to make it as easy as possible!

SD cards can be a bit tricky

Despite all these moves towards more simplicity, when it comes to microSD cards, programming them with your favourite Raspberry Pi operating system has always been a little bit tricky.

The main problem comes from the differences between the operating systems that people’s main computers are likely to use: Windows, macOS, and Linux all use different methods of accessing the SD card, which doesn’t help matters. And, for some new Raspberry Pi users, understanding where to find the latest up-to-date image and how to get it onto the microSD card can be a bit confusing, unless you’ve had prior experience with image-flashing tools such as Etcher.

For that reason, we’ve always suggested that you should buy a pre-loaded NOOBS SD card from your Raspberry Pi Approved Reseller.

But what if you want to re-image an existing card?

Introducing the new Raspberry Pi Imager

Image Utility

No Description

From today, Raspberry Pi users will be able to download and use the new Raspberry Pi Imager, available for Windows, macOS and Ubuntu.

Raspberry Pi Imager

The utility is simple to use and super speedy, thanks to some shortcuts we’ve introduced into the mechanics.

Firstly, Raspberry Pi Imager downloads a .JSON file from our website with a list of all current download options, ensuring you are always installing the most up-to-date version.

Once you’ve selected an operating system from the available options, the utility reads the relevant file directly from our website and writes it straight to the SD card. This speeds up the process quite considerably compared to the standard process of reading it from the website, writing it to a file on your hard drive, and then, as a separate step, reading it back from the hard drive and writing it to the SD card.

During this process, Raspberry Pi Imager also caches the downloaded operating system image – that is to say, it saves a local copy on your computer, so you can program additional SD cards without having to download the file again.

Open source and ready to go!

Download the Raspberry Pi Imager from our downloads page today.

Raspberry Pi Imager is fully open source and was originally written as a modification of the PiBakery tool, later modified and finished by Floris Bos (the original writer of the NOOBS tool and the PiServer tool). You can see Floris’ other software, for data centres, here.

The post Introducing Raspberry Pi Imager, our new imaging utility appeared first on Raspberry Pi.

The Raspberry Pi PiServer tool

via Raspberry Pi

As Simon mentioned in his recent blog post about Raspbian Stretch, we have developed a new piece of software called PiServer. Use this tool to easily set up a network of client Raspberry Pis connected to a single x86-based server via Ethernet. With PiServer, you don’t need SD cards, you can control all clients via the server, and you can add and configure user accounts — it’s ideal for the classroom, your home, or an industrial setting.

PiServer diagram

Client? Server?

Before I go into more detail, let me quickly explain some terms.

  • Server — the server is the computer that provides the file system, boot files, and password authentication to the client(s)
  • Client — a client is a computer that retrieves boot files from the server over the network, and then uses a file system the server has shared. More than one client can connect to a server, but all clients use the same file system.
  • User – a user is a user name/password combination that allows someone to log into a client to access the file system on the server. Any user can log into any client with their credentials, and will always see the same server and share the same file system. Users do not have sudo capability on a client, meaning they cannot make significant changes to the file system and software.

I see no SD cards

Last year we described how the Raspberry Pi 3 Model B can be booted without an SD card over an Ethernet network from another computer (the server). This is called network booting or PXE (pronounced ‘pixie’) booting.

Why would you want to do this?

  • A client computer (the Raspberry Pi) doesn’t need any permanent storage (an SD card) to boot.
  • You can network a large number of clients to one server, and all clients are exactly the same. If you log into one of the clients, you will see the same file system as if you logged into any other client.
  • The server can be run on an x86 system, which means you get to take advantage of the performance, network, and disk speed on the server.

Sounds great, right? Of course, for the less technical, creating such a network is very difficult. For example, there’s setting up all the required DHCP and TFTP servers, and making sure they behave nicely with the rest of the network. If you get this wrong, you can break your entire network.

PiServer to the rescue

To make network booting easy, I thought it would be nice to develop an application which did everything for you. Let me introduce: PiServer!

PiServer has the following functionalities:

  • It automatically detects Raspberry Pis trying to network boot, so you don’t have to work out their Ethernet addresses.
  • It sets up a DHCP server — the thing inside the router that gives all network devices an IP address — either in proxy mode or in full IP mode. No matter the mode, the DHCP server will only reply to the Raspberry Pis you have specified, which is important for network safety.
  • It creates user names and passwords for the server. This is great for a classroom full of Pis: just set up all the users beforehand, and everyone gets to log in with their passwords and keep all their work in a central place. Moreover, users cannot change the software, so educators have control over which programs their learners can use.
  • It uses a slightly altered Raspbian build which allows separation of temporary spaces, doesn’t have the default ‘pi’ user, and has LDAP enabled for log-in.

What can I do with PiServer?

Serve a whole classroom of Pis

In a classroom, PiServer allows all files for lessons or projects to be stored on a central x86-based computer. Each user can have their own account, and any files they create are also stored on the server. Moreover, the networked Pis doesn’t need to be connected to the internet. The teacher has centralised control over all Pis, and all Pis are user-agnostic, meaning there’s no need to match a person with a computer or an SD card.

Build a home server

PiServer could be used in the home to serve file systems for all Raspberry Pis around the house — either a single common Raspbian file system for all Pis or a different operating system for each. Hopefully, our extensive OS suppliers will provide suitable build files in future.

Use it as a controller for networked Pis

In an industrial scenario, it is possible to use PiServer to develop a network of Raspberry Pis (maybe even using Power over Ethernet (PoE)) such that the control software for each Pi is stored remotely on a server. This enables easy remote control and provisioning of the Pis from a central repository.

How to use PiServer

The client machines

So that you can use a Pi as a client, you need to enable network booting on it. Power it up using an SD card with a Raspbian Lite image, and open a terminal window. Type in

echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt

and press Return. This adds the line program_usb_boot_mode=1 to the end of the config.txt file in /boot. Now power the Pi down and remove the SD card. The next time you connect the Pi to a power source, you will be able to network boot it.

The server machine

As a server, you will need an x86 computer on which you can install x86 Debian Stretch. Refer to Simon’s blog post for additional information on this. It is possible to use a Raspberry Pi to serve to the client Pis, but the file system will be slower, especially at boot time.

Make sure your server has a good amount of disk space available for the file system — in general, we recommend at least 16Gb SD cards for Raspberry Pis. The whole client file system is stored locally on the server, so the disk space requirement is fairly significant.

Next, start PiServer by clicking on the start icon and then clicking Preferences > PiServer. This will open a graphical user interface — the wizard — that will walk you through setting up your network. Skip the introduction screen, and you should see a screen looking like this:

PiServer GUI screenshot

If you’ve enabled network booting on the client Pis and they are connected to a power source, their MAC addresses will automatically appear in the table shown above. When you have added all your Pis, click Next.

PiServer GUI screenshot

On the Add users screen, you can set up users on your server. These are pairs of user names and passwords that will be valid for logging into the client Raspberry Pis. Don’t worry, you can add more users at any point. Click Next again when you’re done.

PiServer GUI screenshot

The Add software screen allows you to select the operating system you want to run on the attached Pis. (You’ll have the option to assign an operating system to each client individually in the setting after the wizard has finished its job.) There are some automatically populated operating systems, such as Raspbian and Raspbian Lite. Hopefully, we’ll add more in due course. You can also provide your own operating system from a local file, or install it from a URL. For further information about how these operating system images are created, have a look at the scripts in /var/lib/piserver/scripts.

Once you’re done, click Next again. The wizard will then install the necessary components and the operating systems you’ve chosen. This will take a little time, so grab a coffee (or decaffeinated drink of your choice).

When the installation process is finished, PiServer is up and running — all you need to do is reboot the Pis to get them to run from the server.

Shooting troubles

If you have trouble getting clients connected to your network, there are a fewthings you can do to debug:

  1. If some clients are connecting but others are not, check whether you’ve enabled the network booting mode on the Pis that give you issues. To do that, plug an Ethernet cable into the Pi (with the SD card removed) — the LEDs on the Pi and connector should turn on. If that doesn’t happen, you’ll need to follow the instructions above to boot the Pi and edit its /boot/config.txt file.
  2. If you can’t connect to any clients, check whether your network is suitable: format an SD card, and copy bootcode.bin from /boot on a standard Raspbian image onto it. Plug the card into a client Pi, and check whether it appears as a new MAC address in the PiServer GUI. If it does, then the problem is a known issue, and you can head to our forums to ask for advice about it (the network booting code has a couple of problems which we’re already aware of). For a temporary fix, you can clone the SD card on which bootcode.bin is stored for all your clients.

If neither of these things fix your problem, our forums are the place to find help — there’s a host of people there who’ve got PiServer working. If you’re sure you have identified a problem that hasn’t been addressed on the forums, or if you have a request for a functionality, then please add it to the GitHub issues.

The post The Raspberry Pi PiServer tool appeared first on Raspberry Pi.

GPIO expander: access a Pi’s GPIO pins on your PC/Mac

via Raspberry Pi

Use the GPIO pins of a Raspberry Pi Zero while running Debian Stretch on a PC or Mac with our new GPIO expander software! With this tool, you can easily access a Pi Zero’s GPIO pins from your x86 laptop without using SSH, and you can also take advantage of your x86 computer’s processing power in your physical computing projects.

A Raspberry Pi zero connected to a laptop - GPIO expander

What is this magic?

Running our x86 Stretch distribution on a PC or Mac, whether installed on the hard drive or as a live image, is a great way of taking advantage of a well controlled and simple Linux distribution without the need for a Raspberry Pi.

The downside of not using a Pi, however, is that there aren’t any GPIO pins with which your Scratch or Python programs could communicate. This is a shame, because it means you are limited in your physical computing projects.

I was thinking about this while playing around with the Pi Zero’s USB booting capabilities, having seen people employ the Linux gadget USB mode to use the Pi Zero as an Ethernet device. It struck me that, using the udev subsystem, we could create a simple GUI application that automatically pops up when you plug a Pi Zero into your computer’s USB port. Then the Pi Zero could be programmed to turn into an Ethernet-connected computer running pigpio to provide you with remote GPIO pins.

So we went ahead and built this GPIO expander application, and your PC or Mac can now have GPIO pins which are accessible through Scratch or the GPIO Zero Python library. Note that you can only use this tool to access the Pi Zero.

You can also install the application on the Raspberry Pi. Theoretically, you could connect a number of Pi Zeros to a single Pi and (without a USB hub) use a maximum of 140 pins! But I’ve not tested this — one for you, I think…

Making the GPIO expander work

If you’re using a PC or Mac and you haven’t set up x86 Debian Stretch yet, you’ll need to do that first. An easy way to do it is to download a copy of the Stretch release from this page and image it onto a USB stick. Boot from the USB stick (on most computers, you just need to press F10 during booting and select the stick when asked), and then run Stretch directly from the USB key. You can also install it to the hard drive, but be aware that installing it will overwrite anything that was on your hard drive before.

Whether on a Mac, PC, or Pi, boot through to the Stretch desktop, open a terminal window, and install the GPIO expander application:

sudo apt install usbbootgui

Next, plug in your Raspberry Pi Zero (don’t insert an SD card), and after a few seconds the GUI will appear.

A screenshot of the GPIO expander GUI

The Raspberry Pi USB programming GUI

Select GPIO expansion board and click OK. The Pi Zero will now be programmed as a locally connected Ethernet port (if you run ifconfig, you’ll see the new interface usb0 coming up).

What’s really cool about this is that your plugged-in Pi Zero is now running pigpio, which allows you to control its GPIOs through the network interface.

With Scratch 2

To utilise the pins with Scratch 2, just click on the start bar and select Programming > Scratch 2.

In Scratch, click on More Blocks, select Add an Extension, and then click Pi GPIO.

Two new blocks will be added: the first is used to set the output pin, the second is used to get the pin value (it is true if the pin is read high).

This a simple application using a Pibrella I had hanging around:

A screenshot of a Scratch 2 program - GPIO expander

With Python

This is a Python example using the GPIO Zero library to flash an LED:

pi@raspberrypi:~ $ export GPIOZERO_PIN_FACTORY=pigpio
pi@raspberrypi:~ $ export PIGPIO_ADDR=fe80::1%usb0
pi@raspberrypi:~ $ python3
>>> from gpiozero import LED
>>> led = LED(17)
>>> led.blink()
A Raspberry Pi zero connected to a laptop - GPIO expander

The pinout command line tool is your friend

Note that in the code above the IP address of the Pi Zero is an IPv6 address and is shortened to fe80::1%usb0, where usb0 is the network interface created by the first Pi Zero.

With pigs directly

Another option you have is to use the pigpio library and the pigs application and redirect the output to the Pi Zero network port running IPv6. To do this, you’ll first need to set some environment variable for the redirection:

pi@raspberrypi:~ $ export PIGPIO_ADDR=fe80::1%usb0
pi@raspberrypi:~ $ pigs bc2 0x8000
pi@raspberrypi:~ $ pigs bs2 0x8000

With the commands above, you should be able to flash the LED on the Pi Zero.

The secret sauce

I know there’ll be some people out there who would be interested in how we put this together. And I’m sure many people are interested in the ‘buildroot’ we created to run on the Pi Zero — after all, there are lots of things you can create if you’ve got a Pi Zero on the end of a piece of IPv6 string! For a closer look, find the build scripts for the GPIO expander here and the source code for the USB boot GUI here.

And be sure to share your projects built with the GPIO expander by tagging us on social media or posting links in the comments!

The post GPIO expander: access a Pi’s GPIO pins on your PC/Mac appeared first on Raspberry Pi.