FreePBX is an opensource front-end for the Asterisk VoIP solution. It can be installed on a Raspberry Pi via a prebuilt image but what if you want to use it directly on Raspbian (or other distros)? Well, it is possible with a few minor tweaks.
Because FreePBX and Asterisk are tightly bound it is a permissions nightmare to get the web interface to work with any other user than ‘asterisk’. If you already have Apache running for other purposes then this is obviously not ideal. For this reason we need to get second Apache process running as the ‘asterisk’ user, while at the same time allowing the main Apache process to run as is. Here’s how you do that.
For my next trick I thought it would be nice to have a web interface “colour wheel” to control an RGB LED strip light. These are dirt cheap and usually come with a crappy infrared remote control. The real nice part about this is once you have it working you can do almost anything you want with it – make a gradual sunrise light for the dark mornings, a security light, an auto-off night light or simply pick the colour you want your room to be from a smart phone.
The basic idea of this design is to have the Arduino handle the control of the LED strip itself but allow the RGB values to be set via a serial connection. The Pi will be sending the RGB values via USB to the Arduino which in turn will use Pulse Width Modulation (PWM) to set the intensity of each LED.
After the successful first project of getting a PIR sensor to work with Arduino I thought I’d try something a bit more practical and bespoke. The idea with this is you can use the Arduino to change the colour of an LED if there are any critical or warning errors in Nagios Monitoring software.
This time we’re going to get the Arduino to read input over its USB serial interface from a Raspverry Pi and depending on what it receives either make the LED light green or red.
This Arduino nonsense is actually pretty neat. It’s a small electronics project board with a programmable chip and a pile of General Purpose I/O pins. You can use it to control or be controlled by pretty much anything. There’s tonnes of examples out there from the simple blinking an LED to the much more complex task of automating the watering and lighting of indoor grows. The best of it is this thing costs £5 – five pounds sterling, no shit!
I’m going to try and explain what a decibel is and why it is used so often. For some reason it seems to confuse a lot of people, especially when used in sound engineering. As it happens the dB is actually really simple once you understand what it is and why it is used.
The first concept you need to get your head around is a dB is nothing more than a ratio, just like saying a 2:1 ratio to mean two apples for every pear, in other words double the amount of apples for every one pear. Instead of linear scaling like this, in the land of dB’s everything is logarithmic. You don’t need to know what that means you just need to know that it’s a ratio. First off a bit of history.
There are many tutorials on rebuilding Linux Software RAID but most are unnecessarily overly complicated. It’s fairly straight forward – here’s how.
Unlike hardware RAID, software RAID is all handled by the operating system itself. This means the process of replication, rebuilding and control is performed by the filesystem with various kernel and userspace software.
Sometimes you just have to know something exists before you look into it. IPv6 tunnels may well be a good example. Many ISPs are stuck in the dark ages, what with their archaic attitudes and red tape procedures longer than a trip to Mars.
It’s dead simple to get IPv6 working at home via an IPv6 tunnel broker.
I guess this is somewhat ironic, given their 90’s style logo and website, but these guys provide the tools you need to get your Internet connection this side of the new millennium. Guess what – it’s FREE!
If, like me, you use a Raspberry Pi as a multimedia centre it’s really handy being able to kick off a torrent without having to be logged into the Pi. This is especially useful if you want to download something using your phone, to your Pi, from literally anywhere.
Here’s how to configure Transmission so you can download torrents to your Pi from anywhere.
For a casual bit of weekend fun I thought I’d share a potential method for obtaining your neighbour’s Facebook password. This is purely educational and I used my own systems to do this but it highlights how potentially easy it can be to obtain someone’s login credentials to any website.
We are going to utilise various attack vectors to demonstrate the methodology of the process. The story starts with a hypothetical situation.
Buying speakers is boring, anyone with a credit card can do that. Building speakers is a lot more fun! A year ago a few friends and I decided to build a G-Sub. Here’s the build process in pictures.
Before we start here’s a bit of background on the ‘G-Sub’. Speakerplans.com is a website run by speaker design guru Rog Mogale (Void Acoustics etc). The site contains free designs of various cabinets which anyone can utilise. The G-Sub is a twin 18″ reflex cabinet designed for high fidelity bass at extreme pressure levels. The drivers of choice were Fane Colossus 18XB which are industry standard 1kW (AES) drivers capable of 35Hz – 1kHz with 99dB (1w/1m) sensitivity.