Category: software

Links: A Raspberry Pi controlled mini CNC Laser engraver

[notice]NEVER look into a laser that is capable of engraving materials – you could be instantly blinded!  If you actually have to be told that, then you probably shouldn’t be allowed to use anything remotely dangerous.  DO NOT attempt to build anything like this unless you are willing to take full personal responsibility for any damages.  We WILL NOT be liable if you stupidly choose to build something like this and manage to damage your eyesight, or any other part of your body! And if you do choose to attempt to build something such as this, we strongly recommend mounting it inside an opaque protective enclosure, so that children or animals cannot come into the direct or reflected path of the laser beam.[/notice]

This looks like a fun but potentially VERY dangerous project – we wish the sites linked below had included some common-sense safety warnings for potential builders.  Please be conscious of friends and family members (especially the young ones) that might not fully appreciate the danger.  If there are drunk people around, hide this thing, preferably under lock and key!

I recently made a mini CNC laser engraver using two DVD drives salvaged from old computers and <$10 extra parts bought on eBay. The controller of the CNC machine is a Raspberry Pi, a $35 credit card size computer. The engraver turns out to be pretty successful. So I am sharing it with everyone.

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Full article here:
A Raspberry Pi controlled mini CNC Laser engraver (fun of DIY)

Additional coverage:
Raspi Mini Laser Engraver (Hack A Day)
Raspberry Pi Laser Engraver Created Using Two Old DVD Drives (video) (Geeky Gadgets)
Home-made CNC laser engraver (Raspberry Pi – this article actually does include a warning!)

Link: 5 commands to check memory usage on Linux

Memory Usage

On linux, there are commands for almost everything, because the gui might not be always available. When working on servers only shell access is available and everything has to be done from these commands. So today we shall be checking the commands that can be used to check memory usage on a linux system. Memory include RAM and swap.

It is often important to check memory usage and memory used per process on servers so that resources do not fall short and users are able to access the server. For example a website. If you are running a webserver, then the server must have enough memory to serve the visitors to the site. If not, the site would become very slow or even go down when there is a traffic spike, simply because memory would fall short. Its just like what happens on your desktop PC.

Full article here (tip: if you see a block of run-on text at the top of the page, just skip it and continue on to the next paragraph):
5 commands to check memory usage on Linux (Linux.com)

Link: PlayonLinux for Ubuntu/Linux Mint/other Ubuntu derivatives via PPA

PlayOnLinux is a piece of software which allows you to easily install and use numerous apps and games designed to run with Microsoft Windows. Few apps and games are compatible with GNU/Linux at the moment and it certainly is a factor preventing the migration to this system. PlayOnLinux brings a cost-free, accessible and efficient solution to this problem.

playonlinux

Full article here:
PlayonLinux for Ubuntu/Linux Mint/other Ubuntu derivatives via PPA (Noobs Lab)

Link: How to install webmin on ubuntu 13.10 (Saucy Salamander) Server

Webmin is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely.

Full article here:
How to install webmin on ubuntu 13.10 (Saucy Salamander) Server (Ubuntu Geek)

Link: How to draw flowchart or diagram on Linux

There are several well-known commercial flowchart and diagram software available, e.g., Visio on Windows, OmniGraffle on MacOS X. Then what about Linux? In fact, there are a couple of reasonably good Linux alternatives to Visio or OmniGraffle, for example, yEd, Dia, LibreOffice Draw, Pencil Project, etc.

In this tutorial, I will describe how to create flowchart or diagram with yEd graph editor on Linux.

Full article here:
How to draw flowchart or diagram on Linux (Xmodulo)

Unbricking a Router With a Raspberry Pi using JTAG (links)

This is a tale of how someone remembered that he had a non-functional router, in this case an older Linksys WRT54G, and…

… decided he would have a go at repairing this ancient router. There was only one problem: the most popular utility for programming the router through the JTAG header required a PC parallel port.

Unfortunately, parallel ports are becoming as hard to find as floppy disk drives these days, but did that deter him? No way, he simply added Raspberry Pi support to the debricking utility, and used the Raspberry Pi’s GPIO pins to do the job.  Unfortunately, in the end he was unsuccessful, but only because he physically damaged the circuity on the router while attempting to upgrade the RAM – had he not attempted the hardware modification, this likely would have worked.  So, although we make no guarantees, if you have a bricked router, read the articles linked below and maybe you can bring it back to life.

Unbricking a Router With a Raspi (Hack A Day)
Debrick WRT54GL using Raspberry Pi (JTAG bit banging) (Oxblog)

Link: Mosh – A replacement for SSH

Mosh(mobile shell) is Remote terminal application that allows roaming, supports intermittent connectivity, and provides intelligent local echo and line editing of user keystrokes.

Mosh is a replacement for SSH. It’s more robust and responsive, especially over Wi-Fi, cellular, and long-distance links.

Mosh is free software, available for GNU/Linux, FreeBSD, Solaris, Mac OS X, and Android.

YouTube video link: Mosh: An Interactive Remote Shell for Mobile Clients

Full article here:
Mosh – A replacement for SSH (Ubuntu Geek)

Link: What is Cryptolocker and How Do You Prevent It?

Recently, a new piece of malware has been wreaking havoc online, locking innocent users out of their files and demanding money. Cryptolocker is a form of virus known as “ransomware” – a variety that attempts to extort money in exchange for providing users with what they already own, but can no longer access.

So what is it about Cryptolocker that changes the game, and how do you prevent yourself from falling victim to this vile threat. That is precisely what we want to look at today.

Full article here:
What is Cryptolocker and How Do You Prevent It? (Make Tech Easier)

We would also add that frequent backups to media that is not connected 24/7 is probably a good idea. If you backup to something that requires a user name and password to access, and it’s not already connected at the time the attack occurs, then that data is probably safe. If you happen to have a recent backup made using something like Redo Backup and Recovery, then should an attack like this occur, you can simply wipe the drive clean and reformat it, then restore from your backup and get most of your files back. But that only works if you make the backup before your system is infected, and only if the attacker can’t access your backup file and corrupt that. So if you choose to backup to a network share, make sure it’s a share that you must log into using a strong password before you can access it, and that it’s NOT a share that you normally stay connected to during day-to-day use!

Link: DSVR (Domain-Specific VPN Router)

[notice]This software may not be legal to use in some countries or localities, or for certain uses.  We are not lawyers, so we cannot advise you on this.[/notice]

From the README.md file:

PURPOSE

If you’re using a VPN service today, you may have found the following limitations:

1) All or nothing. Either ALL traffic goes down the VPN or none – unable to be selective.
2) Only one VPN at a time. Cannot selectively route certain sites down one VPN, and others down another VPN.
3) Unless you’ve configured your VPN at the router level, it’s likely that only a single device can use your VPN at one time.

This project serves to address each of the above – see the FEATURES section.

Please review my blog post here http://darranboyd.wordpress.com/2013/07/05/selective-vpn-routing-solution-dsvr/

Note that this software runs on a Raspberry Pi. Full text and download links:
DSVR (Domain-Specific VPN Router) (GitHub)

If for some reason you don’t want to run this on a Raspberry Pi, but would instead prefer to do something similar using a DD-WRT based router, the same author covered that topic a couple of years ago:
StrongVPN PPTP on DD-WRT – Source based routing (improved) (Darran Boyd)

Link: Grsync : Graphical rsync backup tool on Ubuntu (12.10 / 13.04 / 13.10)

grsync is a graphical rsync tool in ubuntu linux. It provides a graphical user interface to backup or sync important files & directories to remote machine or in local machine using rsync. It currently supports only a limited set of the most important rsync features, but can be used effectively for local directory synchronization.

Full article here:
Grsync : Graphical rsync backup tool on Ubuntu (12.10 / 13.04 / 13.10) (NextStep4it)
Related:
How to Install Grsync : Graphical rsync backup tool on Ubuntu ( 12.10 / 13.04 / 13.10) (KBTECHWORLD)