Category: Raspberry Pi

Link: How to build a cross compiler for your Raspberry Pi

A cross compiler is a compiler that runs on one platform/architecture but generates binaries for another platform/architecture. With devices like the Raspberry Pi, where you really don’t have much CPU or memory to work with, if you’re doing any heavy compiling (like when working on the kernel) a cross compiler is the only way to go. For example, I build all my Raspberry Pi kernels on my nice Sandy Bridge Xeon E3 home server where they compile in only a fraction of the time they would on the Pi.

How to build a cross compiler for your Raspberry Pi (Chris’s Digital Realm)

Link: Build an LED Indicator with a Raspberry Pi (for Email, Weather, or Anything)

The Raspberry Pi makes a nice compact platform to attach an indicator light to for all sorts of projects—weather notification, new emails, etc. Read on as we show you how to hook up an LED module to your Pi and set up some basic notifications.

Build an LED Indicator with a Raspberry Pi (for Email, Weather, or Anything) (How-To Geek)

Link: BASH Frequently Asked Questions

Here is something we could have used a few times in the past, had we known it existed:

These are answers to frequently asked questions on channel on the freenode IRC network. These answers are contributed by the regular members of the channel (originally heiner, and then others including greycat and r00t), and by users like you. If you find something inaccurate or simply misspelled, please feel free to correct it!

All the information here is presented without any warranty or guarantee of accuracy. Use it at your own risk. When in doubt, please consult the man pages or the GNU info pages as the authoritative references.

BASH is a BourneShell compatible shell, which adds many new features to its ancestor. Most of them are available in the KornShell, too. The answers given in this FAQ may be slanted toward Bash, or they may be slanted toward the lowest common denominator Bourne shell, depending on who wrote the answer. In most cases, an effort is made to provide both a portable (Bourne) and an efficient (Bash, where appropriate) answer. If a question is not strictly shell specific, but rather related to Unix, it may be in the UnixFaq.

This FAQ assumes a certain level of familiarity with basic shell script syntax. If you’re completely new to Bash or to the Bourne family of shells, you may wish to start with the (incomplete) BashGuide.

If you can’t find the answer you’re looking for here, try BashPitfalls. If you want to help, you can add new questions with answers here, or try to answer one of the BashOpenQuestions.

Link: BASH Frequently Asked Questions

Over 100 questions are answered here. And in case you missed it above, this page only shows the questions – you have to click on the links that follow each question to see the answers.

People often don’t realize how powerful BASH really is. Very often people will try to write a program in a higher level language to do a simple task that could easily be done entirely in BASH. Look this page over and you might realize that you can do a lot more with BASH than you thought. And BASH is available in every version of Linux we’ve ever encountered (note we did not say “installed by default”, though it often is nowadays). Even small computers such as Raspberry Pis will usually have BASH installed as part of the operating system.

Link: How to set up a VNC server on a Raspberry PI, a VNC client on an Android device, and use the two together

I think the title above more accurately describes what is shown in this article than the tile they picked. Just good basic information on how to do this:

Connecting via VNC to Raspberry PI from the Google Nexus 7 (Everyday Linux User)

Asterisk on a Raspberry Pi – which distribution is best?

Portions of this article were UPDATED July 20, 2016, mostly to include information about Raspivo.

To the best of our knowledge there are five projects that will allow you to run a PBX on a Raspberry Pi. They are:

In this discussion we are only going to consider the first four, because FusionPBX runs on top of FreeSWITCH, not Asterisk. And we have nothing against FreeSWITCH, but it’s never been big among home users and experimenters. Perhaps that should change, but for now we just want to consider the Asterisk-based distributions.

It does not seem as though µElastix ever really caught on with a significant group of English-speaking users, and therefore it would be difficult to offer any sort of opinion. But we will note that new users and those not all that familiar with Linux may have a bit more trouble with the installation process, since there is no image file provided as is the case for some other distributions. One potential advantage of µElastix is that it will run on a Raspberry Pi, PicoSam, or Mcuzone, though you are not likely to run into the latter two boards anywhere in North America.

As for Incredible PBX, this takes the typical Nerd Vittles/PBX in a Flash “throw in everything but the kitchen sink” approach, but then offers this ominous-sounding advice:

Here’s everything you need to know about security for Incredible Pi:


What this basically means is that you can’t have any off-site extensions that register with your Asterisk server, if you heed their warning.  Well, you CAN, but not in any way that’s convenient for end users.  The problem apparently is that a few years ago someone connected with that project got hold of an article or two where someone got a huge phone bill by having an unsecured PBX, and had a major freakout about it.  There were probably several security failures associated with those incidents, but here is our question:  Since nobody in ANY other PBX project we’ve ever encountered gives advice like this, does this mean that Incredible PBX is incredibly insecure by design, and the only way to properly secure it is to take extraordinary steps such as these?

We’re not saying that all of this advice is out of line – the first point is probably a very good idea whenever possible – but most home users will be doing that anyway.  But it’s we particularly take issue with.  If you want to have any external extensions, you pretty much need to forward UDP ports 5060 and 10000-20000 to your Asterisk server.  And the Incredible PBX people specifically tell you not to do that, rather than recognizing that for some users that is simply not a viable option.

The other issue we have with Incredible PBX is that it includes a lot of what we would consider frivolous add-ons.  The main reason people generally install a PBX is because they want to use it to make phone calls, and perform a few other basic functions such as record voicemail, let callers select a destination from an auto-attendant, and so on.  All of these basic functions are provided by FreePBX, and all the other add-ons are pretty much useless unless you are just installing a PBX to play with features.  We can just about guarantee you that 99 percent of your users will not care that they can dial a code and get tide reports, or some similar nonsense.  On a regular server that has a lot of CPU power and storage space, having a bunch of extras may not be a problem.  On a Raspberry Pi, however, you are probably going to want a lean, trim installation that doesn’t get in the way of the basic functionality of a PBX.

I’ve seen reports in mid-2016 that Incredible PBX will soon (and perhaps already does) offer a menu at installation where you can select which features you want. However you will need to choose carefully because if you reject an option and then later decide you want it, you might need to reinstall from scratch to get it. New users might not know which features are actually useful and which are needless bloat, but at least it appears some effort is underway to stop forcing users to take all or nothing.

Raspivo is based on XiVO, which has been around for a while but was relatively unknown in the English-speaking world until fairly recently. However it has generated a lot of interest due to users desiring an alternative to FreePBX, which seems to be getting less “free” (in all senses of that word) as time goes by. There is a discussion about XiVO on DSLReports that you may wish to read, which in turn contains several other useful links. My understanding is that the “official” English language translation of the installation instructions are somewhat out of date, so you may find that RonR’s instructions on DSLReports are easier to follow. Like FreePBX, XiVO is a GUI interface for Asterisk, so any custom dialplan you have written for another build of Asterisk should be usable (perhaps with minor modification) in Raspivo. It appears that you must have at least a Raspberry Pi 2 or newer to run Raspivo.

If you have no experience at all with software PBX’s and are just getting your feet wet, but you are not unfamiliar with programming, XiVO is the one I’d suggest. It makes repetitive tasks easier but doesn’t get in your way when you want to customize your system to the same degree that FreePBX does. However if you just want everything to be as easy as possible, and you never want to do any dialplan customizations (or only very limited ones), then you may want to consider Asterisk for Raspberry Pi, also known as RasPBX.

The RasPBX distribution includes Asterisk and FreePBX, with additional scripts that will optionally let you install HylaFAX and/or Fail2Ban. There is also a related version of this software for the BeagleBone Black. This software is relatively easy to install, comes with no ominous security warnings, and doesn’t include a lot of “bloatware”, which we think is a definite advantage. They also have a semi-active discussion forum where you can find several installation and usage tips. And it is possible to run RasPBX from an External USB HDD or Thumb Drive, in case you are worried that running a PBX off of an SD card might not be reliable, although there are ways to minimize writes to the SD card if you prefer not to have the added power drain of another device.

We realize that none of these distributions are absolutely perfect, and everyone will have their own reasons for picking one over another. The PBX in a Flash forum used to include a Raspberry Pi board, but it was apparently lost in their “Great server crash of 2013”, and they never bothered to reinstate it. So it seems that for them, the Raspberry Pi is just one of many platforms they are attempting to support, and it does not appear to us that they are making much of an attempt to optimize their software specifically for the Raspberry Pi. We might receive a few less than gracious comments for saying that, but that’s simply our observation, and others are free to disagree – we just recall the old saying, “Jack of all trades, master of none” and feel it might apply in the case of putting out a version of Incredible PBX for the Raspberry Pi that includes pretty much everything that the versions intended for larger servers include. For performance reasons, we’d prefer to stick with a distribution designed for the Raspberry Pi from the ground up, and therefore our preference has always been Asterisk for Raspberry Pi / RasPBX, though nowadays we’d suggest that anyone that wants to have complete control over their system might also consider Raspivo. Just be aware that the learning curve with Raspivo might be a bit steeper.

If you disagree, feel free to try any of the other distributions mentioned. That’s the nice thing about having choices – you can try various programs until you find one that meets your needs, and maybe even your wants.

One final point – since this article was originally written in 2013, new versions of the Raspberry Pi have appeared, and some of the above-mentioned software may have been updated to only run on newer models. Or they may run, but only painfully slowly, if you have an original Raspberry Pi. In particular, it appears that Raspivo will only run on the Raspberry Pi 2 or newer. So if you have a first-generation Raspberry Pi, pay attention to the system requirements for the software you are downloading, because you might need to seek out an alternate or older version of the software.

Links: How to extend the life of the SD card on a Raspberry Pi (or similar device)

People are using the Raspberry Pi for many applications these days, including as a VoIP PBX server based on Asterisk. One thing that many people forget is that you can only write to an SD card a limited number of times before it fails. Asterisk in particular likes to write a LOT of information to log files, and let’s face it, if you are honest and you are like 99% of Asterisk system administrators, you will admit you never read them unless perhaps you suspect there is a problem with your system. Yet every one of those many writes reduces your SD card’s lifespan by a small amount.

So with that in mind, here are links to a few threads that may or may not be helpful, in no particular order:

How can I extend the life of my SD card? (Raspberry Pi Stack Exchange)
How can I use a USB HDD to extend the life of my SD Card? (Raspberry Pi Stack Exchange)
Read/Write cycles of a SD card (
Extending the life of the SD card (RasPBX – Asterisk for Raspberry Pi/Sourceforge)
How to add ‘noatime’ to fstab? (AYK solutions)

Know of any other good links on the subject? Please leave a comment!

Cubieboard2 open single board computer ships, Cubietruck model revealed

This comes to us from LinuxGizmos:

The forthcoming Cubietruck will have additional I/O ports
The forthcoming Cubietruck will have additional I/O ports

The Cubieboard open SBC project began shipping a faster Cubieboard2 version of its open source Linux and Android SBC, and revealed prototypes of a new, larger, enhanced Cubietruck model. Like the $59 Cubiboard2, the Cubietruck uses an Allwinner A20 dual-core Cortex-A7 SoC instead of the original’s single-core Allwinner A10, and adds a 2GB RAM option, WiFi, Bluetooth, gigabit Ethernet, VGA, and SPDIF ports.

Read the full article here.

Note that the abbreviation “SBC” in the above-linked article stands for “single board computer”. In our opinion, if the Cubietruck works reliably it could relegate the BeagleBoard Black to also-ran status, and could even give the Raspberry Pi a run for its money among those who’d like just a bit more power and a wider selection of outputs. For Home Theater PC builders, the inclusion of a SPDIF Toslink optical port is no small thing. We’ll definitely be keeping an eye on this one!

How To Use The Raspberry Pi As A Wireless Access Point/Router, and other Raspberry Pi tricks

Just some quick links for the Raspberry Pi fans out there, from a multi-part series of articles on “How To : Use The Raspberry Pi As A Wireless Access Point/Router” via a blog called The Rantings and Ravings of a Madman:

Part 1 — How to create a Wireless Network On Your RPi
Part 2 — How to make your RPi into a Wireless Access Point
Part 3 — How to make your RPi into a Router
Part 3B – Issues with HostAPD ? Click here!

But the author of this blog didn’t stop there. Here are a few of his more recent articles, in a similar vein:

Script : WiFi Checker Script
Script : Starting hostapd when WiFi goes down
How To : Turn the Raspberry Pi Into a Shaping WiFi Router
Script : Web Configuration Page for Raspberry Pi
How To : Use A RT5370 USB WiFi NIC In A Bridge

And in case you are thinking that the only things he knows how to do with a Raspberry Pi involve WiFi, guess again! Here is a link to all his Raspberry Pi related posts.

If you have an RSS newsreader, you might want to add his feed, or follow him on Twitter to get notifications of his latest blog posts.

If you know of any other great blogs for Raspberry Pi users that are of the same caliber as this one, please feel free to let us know in the comments!

Link: Build Your Own Raspberry Pi Case from Cardboard or Cardstock

From a company that sells Raspberry Pi’s in North America comes this:

One of our top selling accessories for the Raspberry Pi is the case. Cases for the Pi come in a multitude of styles, sizes and colors, but if you’re like us, you’re the type of person who loves to build it yourself. Today we’re going to build a bare-bones case out of cardboard with supplies you may already have laying around the house.

Read the rest of the article here:
Build Your Own Raspberry Pi Case from Cardboard or Cardstock (MCM Electronics)

In case you are wondering, the finished enclosure looks something like like this (depending on what you make it out of). Just be sure to use a non-conductive material:

An alternative way to power a Raspberry Pi

Did you know that you can use a $20 USB hub (but not just any old USB hub) to power a Raspberry Pi AND use the SAME hub to add additional USB ports to the Pi? Well, you can, as demonstrated in this video:


Direct YouTube Link

Apparently not all USB hubs will work, because many only put out something close to the 500 mA that is the specification for USB 2.0, whereas the Raspberry Pi Model B requires 700 mA. So, the hub has to put out a bit of extra current or it won’t power the Raspberry Pi properly.

There is a list of USB hubs that will work with the Raspberry Pi, but pay special attention to the comments in the rightmost column. Only a few of the USB hubs shown are known to be able to power the Raspberry Pi reliably. The one shown in the video is the Plugable 7 Port High Speed USB Hub, model USB2-HUB-AG7 (Amazon affiliate link – we make a small commission if you click on it and purchase a unit).

EDIT: A few weeks after we originally posted this article, the device described in the following article was released:

PiHub from Cyntech and Pimoroni – a new powered USB Hub for the Raspberry Pi

Unless you really don’t need that many USB ports, and you absolutely fall in love with the Raspberry-shaped case of the PiHub, we suggest you stick with the Plugable 7 Port hub mentioned above. Not only are you getting more USB ports, and a hefty 3 Amp power supply, but if you’re in the U.S.A. or Canada it’s actually available here and has mostly 4 and 5 star reviews on Amazon. And if you go with the PiHub, by the time you do the currency conversion (and let your credit card company take a small bite on the exchange rate), and pay for the shipping, you’ll be paying more and getting less (only four ports rather than the seven offered in the Plugable unit). But, you will be getting that lovely Raspberry-shaped case, so there’s that.

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