Sharing attached USB storage in OSMC using NFS

As well as being attached to the living room TV for use as a media centre, I also wanted to be able to use my Raspberry Pi 3 B+ as a simple NAS for other TVs in the house to stream from.

The Pi I’m using has a 1Tb desktop hard drive attached to it over USB, and I wanted a way to easily share the contents. It was actually relatively easy to set up… this is how to do it in OSMC;

  1. Install SSH to OSMC via the Store
  2. Now you can remote shell into the Pi to set up the network share
  3. Install NFS services using the following command;
    sudo apt-get install nfs-kernel-server
  4. Edit the file shares;
    sudo nano /etc/exports

    Add a share like this;

    /media 192.168.1.0/255.255.255.0(rw,fsid=0,insecure,no_subtree_check,async,crossmnt)

    (crossmnt fixed an issue where I could see the folders but no files)

  5. Restart the NFS service;
    sudo /etc/init.d/nfs-kernel-server restart

That’s it.. you should now be able connect to the Raspberry Pi and see the files on any of the USB drives you’ve got attached.

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Automated mains socket power-off for OSMC on a Raspberry Pi

I’ve chosen to replace an ageing mini-PC which I’ve used since 2010 with a new Raspberry Pi 3 B+ running OSMC. It makes for a really capable media centre which can playback newer h.265 HEVC video files at 1080p without any problems, or it can serve 4K files over NFS to a box with a hardware h.265 chip like the Fire TV Box.

This form factor is easy to take on holiday and you can use an old infrared remote control (or Harmony learning remote) with it too.

However, the one thing I’ve struggled with is how to make it easy for my family to use in regard to switching it on and off. The Pi doesn’t have a power button. Some power supplies have an inline rocker switch, which almost fits the bill. I wanted something more automated.

Fortunately I had a spare Energenie power socket from a previous project where I use one to turn off our bass speaker when the TV isn’t on. These power sockets are controlled remotely (over RF) from a Pi which you attach an Energenie control board/shield to.

What I’ve done with the Pi 3 is have it powered through an Energenie socket, and set up a service that executes when it detects OSMC is shutting down. That service will make a quick HTTP call to the Pi with the Energenie controller shield, which will in turn send an RF signal to turn the mains socket off.

 

osmcshutdown

 

Here’s how you can set it up like I have…

Scripts for the Pi running OSMC

First, add a new service script.. create a new file in this folder;

/etc/systemd/system/callenergenie.service

Then enable it with;

sudo systemctl enable callenergenie.service

There are a couple of useful things happening in this service, the After parameter makes sure the code runs before the network code is shut down, and Conflicts parameter is looking for OSMC shutting down.

Now add a helper script… this will make the webserver call as a background task, so control will be given back to the service immediately, rather than it waiting for the wget to complete.

/home/osmc/callenergenie.sh

This calls the PHP script, telling it which socket to turn off, and how long to delay before sending the command, which we’re doing so that the Pi has time to shut down before the power is cut.

Scripts for the Pi with the Energenie shield

This is the PHP script I added to the other Pi which was already configured to be a PHP web server.

/var/www/html/callenergenie.php

To allow PHP to run the script as root, I needed to add the Apache user to the list of sudo-ers.. not that secure tho :( I’d be interested in anyone who knows how to run the Energenie scripts a regular user.. their Python doesn’t like it when it’s not root.

nano /etc/sudoers

www-data ALL=(ALL) NOPASSWD:ALL

The nice thing about the PHP script is that we can actually call it to turn the Pi on remotely too.. so you could configure that into a widget on your phone, or add it to Alexa.

Basic Automated Testing using FeatherTest for Chrome

There are a fair number of automated testing tools out there like Intern or Puppeteer, but I wanted something super simple and quick to set up to test a variety of pages on a site I develop.

I was making changes to JSON-LD, page metadata, and some of the data that’s sent to Omniture analytics. All the pages types are slightly different, containing things like Documents, Discussions, Blog Posts, landing pages, etc. So I needed to go to a variety of URLs on my local dev environment to see what certain DOM elements got set to, and check the contents of some JavaScript variables.

I’d then need to do the same checks against our Dev, Staging and Production servers to make sure they all looked correct there too.

After a bit of searching I came across FeatherTest which is fed a text file where you use JavaScript/jQuery to define & run the tests.

It’s very easy to set up tests, and the same test script file can be run against whatever site you’re looking at in your browser. For more info go here;

https://xaviesteve.com/5302/feathertest-automated-website-testing-extension-google-chrome/

Typical FeatherTest Script Structure + Syntax

Tip 1 – Preserve Log

The output from FeatherTest goes into the console, so if you’re testing multiple pages, you’ll need to check the ‘Preserve Log’ option, otherwise you’ll lose the output as Chrome navigates between pages.

Tip 2 – Output Formatting

When writing scripts, I’d recommend colouring the console output, and prefixing each line with something easily identifiable. In my case I’m using ‘SUDO – ‘ and colouring the text orange.

You can then simply filter the console to just see your output;

When you’ve filtered the output, you can then save it to a file (right-click, save as..) and format it into shape.

I’ve found this really useful to monitor how my SEO data has improved as I’ve made changes, and to sanity check I’ve not broken anything between releases.

Tip 3 – Variable access

Some of the test scripts I’ve written needed access to variables defined in the scope of the main window.. FeatherTest can’t normally access these variables, so we need a helper function.

The helper function either needs baking into your site’s JavaScript, or you can inject it using an extension like TamperMonkey. Using TamperMonkey means you can use it on whatever site you want, not just ones where you’re able to install the function on.

My code adds an event listener that you can call from FeatherTest which you can request variable values from.

e.g.

window.postMessage({ "action": "variable", "value": "myVar.hierarchy"}, window.origin);

This is the TamperMonkey/GreaseMonkey script I use;

FeatherTest Script – Example 1 – DOM Lookup

Pulling data out of the DOM is straightforward;

FeatherTest Script – Example 2 – Variable Access & JSON-LD

To access variables we’ll use the TamperMonkey function I posted above. We can also pull out any JSON-LD splats and present them quite nicely in the console output.

 

Adding IR Remote Control Support to the Raspberry Pi

In my last post I took you through how I created a small portable media centre that I can easily take on holiday to hook up to the hotel TV.

To reduce the amount space it took up, I used a cheap USB keypad which could be used to control the media center. It worked really well & having something hard-wired meant I didn’t have to worry about a Bluetooth-paired device needing re-pairing.

However, what I then realised was it would be good to be able to use a spare remote control instead. I was using the OpenElec distribution and looked through their documentation for how to do this, but only found references to version 3 of the software (it’s on version 7) and how to get LIRC working with it. There were plenty of blog posts on hooking up IR support, but a lot of them were written 2-3 years ago, and the software has moved on somewhat.

Hardware Setup

What I did first was buy a suitable IR receiver. I chose the Vishay TSOP4838 (which costs less than £1) because of the voltage range (2.5-5.5v) and receiver frequency (38KHz). If you look at the datasheet for the product, you’ll see which pins should get wired up to the Pi;

Simply wire pin 1 to GPIO 18, pin 2 to GND, and pin 3 to a 3.3v power pin, e.g.

By using some short F-F jumper wires and a small cut in the side of the case, I was able to position the reciever neatly(ish) on the side.. it’s still easily removable, but you could integrate it into the case a bit more seamlessly than this ;)

Software Setup

Before this project I was using OpenElec, but had limited success getting the IR support working properly. I switched to OSMC which I’d read had better IR support through the main UI. I think I was actually on the right track with OpenElec, but I realised later that the old vintage Xbox remote I was trying to use wasn’t 100% working.

If you’re going to use a remote control that’s officially recognised, then you can jump this part about learning IR remote control codes.

Learning IR remote commands

The remote I found in the loft was an old DVD player remote which (unsurprisingly) wasn’t in the list of pre-recognised remotes in the OSMC installation. I needed to get the Pi to learn the IR pulses being sent out by the remote and map them to the Kodi functions.

1. First off, you need to telnet to the Pi. Username: osmc, Password: osmc.

2. Next you need to stop the LIRC service which is being locked/used by Kodi

sudo systemctl stop lircd_helper@lirc0

3. Now you can run the IR learn mode.. this will record what it finds to the config file you specify;

irrecord -d /dev/lirc0 /home/osmc/lircd.conf

4. Follow the on-screen instructions which will recognise your remote.

One observation I had was that this only worked properly if I stopped after the first prompt to press lots of keys on the remote.. if I completed the second stage, the key mapping didn’t work, e.g.

If I ignored the second phase & let it abort, the learn process worked

When it’s working, you’ll be able to enter the Kodi function (like KEY_UP, KEY_DOWN, etc) & map it to a key press on your remote;

Once you’ve mapped all the functions you want, we then need to move back to OSMC and tell it to use that config file we’ve just written.

OSMC Settings

In OSMC you need to do the following;

1. Disable the CEC service (via System Settings > Input > Peripherals > CEC Adapter), which seems to be needed for LIRC to work.

2. Now go into OSMC settings and pick the Raspberry Pi icon

3. Go into Hardware Support and enabled LIRC GPIO Support. You shouldn’t need to change anything if you connected the sensor to GPIO 18.

4. Now go back and select the Remote Control option.

5. Ignore the list of pre-installed remotes and select Browse;

6. Navigate to the folder where LIRC wrote your config file;

7. Confirm the change & reboot the box;

That should be it.. your remote should be able to control everything in Kodi.

Portable Raspberry Pi Media Center

We recently went on holiday and I took my laptop & VGA cable with me. It was my intention to hook it up to the TV and play some media on it to keep the kids happy on rainy days. However, It turned out the TV had the VGA port covered up by the wall mounting bracket, and my laptop doesn’t have HDMI.. so we ended up putting the laptop on a chair and watching videos from there; it did the job, but wasn’t ideal.

At home we have a Fire TV Stick that could run Kodi, but the problem with Fire TV is that it has to have an internet connection, otherwise it doesn’t work (you can’t even get to Kodi!). Tethering it to my phone isn’t an option, since there are poor mobile signals in a lot of the places we visit.

Next time I’m going to be more prepared, with a more compact and flexible setup consisting of a Raspberry Pi 2 running OpenElec (and Kodi) together with a set of cables allowing me to hook it up to pretty much any TV. The Pi 2 runs Kodi really well, and the OpenElec distribution boots really quickly & has good Wifi and BlueTooth support. I initially chose a compact/travel USB-based keyboard instead of Bluetooth in case OpenElec ‘forgot’ the keyboard and I’d have nothing to navigate the menus to re-pair it.

Cable-wise, I’ve got a 1m standard HDMI cable, which will be fine in most situations.. with a 2m HDMI extension lead if I can’t get the Pi near enough to the TV (some accomodation doesn’t have power sockets where you’d expect them). I’ve also got a RCA lead, with a SCART adapter as well.. so that helps if we get stuck with an older TV.

For media storage I’ve gone with a USB3 Flash Drive with a capacity of 64Gb, which gives us more to play with than the microSD card, and it’s super-fast for copying media from a PC. As soon as you plug in the flash drive, Kodi will show it in the menus.

So that’s it.. nothing groundbreaking or overly difficult to put together. The whole system is small enough to fit in a small travel bag & gives us a lot of flexibility when dealing with different hotels/accommodation. You may just find the TV accepts the USB flash drive and can play back whatever is on it.. but at least you’ll have all the gear you need if it doesn’t ;)

After I made the video, I bought a USB numeric keyboard from eBay for a paltry £2.. that’s compacted the kit even further, allowing it to fit in an old camera bag.

The keypad isn’t instantly recognised by Kodi, but an easy way to get it up and running is to use the Keymap Add-on. Attach a normal USB keyboard and the keypad at the same time.. start the add-on and use the keyboard to activate the remap process. From there, it’s dead simple to map the keypad to the different Kodi functions.

Here’s the full kit list;

1 x Raspberry Pi 2
1 x 8Gb MicroSD card
1 x 2m HDMI extension cable
1 x 1m HDMI cable
1 x USB numeric keypad
1 x RCA to SCART adapter
1 x 3.5mm plug to RCA lead
1 x 64Gb USB3 Flash Drive
1 x USB power supply + cable

Update 1:

Just got back from a week at Center Parcs (Woburn) and was really pleased to find a HDMI socket on the wall, and a power socket.. it made it super easy to hook up the Pi to the TV :)

Update 2:

We spent a week near Blackpool, and the accommodation we stayed in had a patch panel as well! Seems like they’re quite common these days :)

 

17 Extensions to help the transition from Firefox to Chrome

I’m finally done with Firefox. When I first started using Firefox, the add-ons were a game-changer & I loved how much extra functionality they added to my day-to-day work.

Today, Chrome dominates the market, is waaay faster, and at the end of 2017 Mozilla is changing the add-on framework so some of the ‘classic’ add-ons I use will cease to work.

The final straw was seeing how fast Chrome way for general browsing and content creation; so much snappier than Firefox. Maybe that’s down to an ageing Firefox user profile.. but, IMO, Chrome is the future.

To ease my transition from Firefox to Chrome I’m using a bunch of extensions that give me the features I’ve grown used to. I thought I’d list out what I’m using so that others might benefit from knowing they’re out there & how useful they can be.

Adblock Plus
Blocks adds. I’d tried uBlock.. but found it breaking a bunch of sites.. so back to this one I’ve used for years in Firefox.

Akamai debug headers
Makes it simple to see what’s happening with websites fronted by the Akamai CDN.

Awesome Screenshot
Full-page screenshots

Cookie Inspector
Enables editing + adding of Cookies (I guess one day the Chrome devs will add this into the core app.. one day).

Downloads Router
Routes certain file types to certain folders. Bit of a faff to set up, but I find it useful for filing downloads into set folders.

Fauxbar
The Chrome omnibar isn’t great for finding URLs I had open hours/days ago (Firefox was brilliant). This sorts out that problem & does a pretty good job at indexing everything nicely.

In addition to that, it gives you a neat menu bar with shortcuts to a whole bunch of things; bookmarks, extensions, apps, options, etc. The configurable tiles for sites is super-handy too.

HostAdmin App
Quick and easy host file editor.. especially useful if you’re using proxy exceptions to speed up access to certain internal sites, and want to be able to configure or toggle the entries easily.

LastPass
Excellent cross-device password manager.

ModHeader
Modify browser headers. Useful for testing things like GeoIP.

Open IE
Adds in a context menu to open the current URL or link in other browsers (IE, Firefox, Opera, etc). Need an external helper program installing in Windows.

Page Monitor
Monitor web pages for changes.. works best when you set the Advanced option to look at a particular part of the page using CSS selectors.

Proxy SwitchyOmega
Set up multiple proxies and easily switch between them via the toolbar button.

SimpleUndoRecents
This will give you a button where you can undo the accidental closing of a tab. (TabMixPlus did something similar in Firefox).

Tampermonkey
Lets you run scripts against web pages each time you load the page.. essentially allowing you to alter the page after it renders. Super handy for removing or adding elements to the page. This extension is the equivalent to Greasemonkey on Firefox.

The Camelizer
Nothing to do with work.. but essential all the same. Lets you see the price history for products on Amazon.. and set alerts for price fluctuations.

Web Developer
Handy tools for developers.

Xmarks Bookmark Sync
Synchronise bookmarks between multiple browsers on multiple PCs.. even has version history in case you delete bookmarks by accident.

 

Honorary mention..

An extension called Postman would have made this list a few months ago.. but it’s moved to a stand-alone application for Windows + Mac. It’s another essential bit of kit for developers; if you’ve not checked it out, go take a look.

MIA…

That covers all but one of the Firefox add-ons I used to use. The one I still miss is Locationbar2, which I simply can’t find an equivalent for in Chrome.

It essentially makes each part of a site’s URL a clickable link.. which is super handy for quickly moving through a site’s structure.

If anyone spots something suitable, hit me up in the comments.

Raspberry Pi Heating Controller – Part 2 – Software Architecture

One of the early design decisions for the Raspberry Pi powered heating controller was to have the Pi secured behind a firewall without direct access to it from the Internet. What I decided to do was have a set of simple PHP web pages on a remote web host that you can access from anywhere, and the Pi control server talks to that web host to send/receive data.

What I didn’t want was for the Pi to run a web server that ends up getting compromised & having the run of my home network.

arch-mode1
The Pi server and remote webspace need to be paired with an access key. Anyone accessing the remote site needs the correct access key to be able to control the system.. and the level of control is limited by the API we’ll put in place.. i.e. remote clients won’t have direct access to your internal network via an open port on your home router.

Of course, you could actually host the ‘remote’ part of this set up on your Pi and use port forwarding; the architecture allows for both types of access. The access key is still needed to control the system, but you’ll be more vulnerable to attacks on your Apache/PHP installation & need to keep up-to-date with software patches to help ensure your system is secure.

arch-mode2