Busy hands | Disquiet mind

An Arduino microcontroller can generate a square wave on PWM pins to simulate an analog wave. But the wave alternates between 5V and 0V, it doesn't change polarity.

If you have a component that expects an AC signal you need to change the 0V to 5V signal to a -5V to 5V signal.

One simple way to do this is with a SparkFun Transceiver Breakout. Connect the Power pin to either 3.3V or 5V on the Arduino, GND to GND, T2IN to a PWM pin, and T2OUT to your component. analogWrite() your required frequency to control your component.

Back of SparkFun Transceiver Breakout with labelled pins visible
Photo by chebe

Let's try a post without pictures for now. How to get an unaffiliated cloak on freenode:

Step 1; register a nickname [as detailed here]
Step 2; join #freenode and wait patiently for a staffer to show up
Step 3; ask politely for a cloak [as here]
Step 4; once cloak is applied, thank your staffer, and check your info

Simple, and awesome. Going to test it from work tomorrow to see how well it works.

*edit* Using the webchat.freenode.net clients still set the realname to something based on your ip, but using a client that sets realname to something silly like 'purple' (hi pidgin), is a pretty good combination.

We have many different kinds of Operating Systems, each with its own pluses and minuses. I think this is a very good, and important, thing. It means you have the scope to find the one that suits you just right, to enable a kind of symbiosis between you and your machine. I remember the days when you had to use Windows. I, everyday, encounter people who tell me I have to use Mac. Multiple times a day I come across people who tell me why their *nix flavour is the best. It drives me nuts. In my personal sphere the worst offenders are the Debian and Ubuntu users. I've no problem with people talking about their OS, engaging in open discussion is healthy and enlightening. It's when that conversation happens to the exclusion of all other OSs that I get annoyed. And not simply because I'm a Fedora user.

Increasingly in college we're having Ubuntu forced upon us. It makes sense, there are people in my course unfamiliar with linux, and it is widely believed to be the easiest to get into. But, they say X works with linux, when they mean Ubuntu. They give instructions only for Ubuntu. Documentation is only written for Ubuntu. There is a massive dependency on "do this and it just works". Only, when you're on another flavour, and trying to figure out why it doesn't, there are no pointers, and the instructors can offer no help. It kinda defeats the purpose don't you think? To replace one ubiquitous system with another, with equally limited knowledge of how it actually works.

Okay, my little rant is over. Here's some things you might find helpful, if you're a Fedora user.

When you yum install python you mightn't get everything you need. I was told to get python-usb, what I needed was yum install pyusb.

If you're doing a forensics course and you're being told to grab things like vinetto and reglookup you'll notice they aren't in your repos. You need the CERT repo. Save the PGP key, and add it: rpm --import forensics.asc. Download the repo rpm for your version of Fedora, and install it: rpm -ivh cert-forensics-tools-release-13.rpm. (I realise I do this in a kooky way, and there are probably better ways, but I'm set in mine :) Now, updatedb to sync before you use yum. You can install everything: yum install CERT-Forensics-Tools, or just what you're looking for, e.g. yum install reglookup.

gvimdiff. I had vim installed, I'm pretty sure I had diff installed. But I couldn't get gvimdiff (or vimdiff) to work. It magically sorted itself out when I realised the g => yum install vim-X11.

There, now we can all get back to enjoying the diversity.

Ever get that oddly uncomfortable feeling whenever you sit down to use a computer that's not yours? Even if it's the same OS, everything is just in the wrong place, all your shortcuts missing, it's distressing.

Ever wanted to simply bring your Desktop around with you, no matter where you are?

First thing you might try, especially if you're a Linux user, is persistent Live USB. Like a Live CD, only on a USB stick, and you can save files to it.

Put the Live CD into the CD-drive. Reboot your machine, and at the BIOS make sure the CD-drive has priority in the boot list.

If you're using the Ubuntu 10.10 Live CD it will ask you to either try it, or install it. Try it.

Plug in the USB key (2.6GB+), and wait until it automagically appears on the Desktop.

Go to the menu: System > Administration > Startup Disk Creator

The iso and USB key should be auto-populated, but check to make sure.

The slider is how much persistent storage you want. For me it went up to 4GB (for an 8GB stick).

Press the 'Make Startup Disk' button. Wait.

When done you will have a bootable Live USB disk with persistent storage.

(Don't want to burn a CD? You can download the iso, and use the in-built Live CD creator tools, most distros have them. Or use UNetbootin (Windows version too).)

Great? Well, not really. Every single time you boot in it asks you to Try It or Install It. That takes extra time, it gets annoying. What I really want is a portable computer drive, an OS on a stick!

So I can just choose Install It and point it at the USB key? Nope. It will pick up your hard-drive and try to include those existing partitions. Which will either mess up your existing MBR/grub/lilo/etc, or mean the key will only boot in that machine. Some people say to disable the hard-drive in BIOS, then try it. My older laptop doesn't have a BIOS option to disable the hard-drive, and when I tried it on my EEE it also disabled its ability to detect my USB flash key (a type of hard-drive). So, I was left with one alternative. (Okay, so there are others, but this is the simplest.)

Remove the hard-drive.

Boot into Live CD (iso no good here as the hard-drive is gone).

For Ubuntu: Choose Try It. Then plug in USB key, when it automagically appears, start the Install, either from the Desktop icon or the menu.

For BackTrack: Choose Live CD from the boot menu. Type 'startx' for a graphical interface if so inclined. Plug in the USB key. Run install.sh on the Desktop.

Make sure it picks up your USB key, and only your USB key. Continue installation as usual.


There. Done and dusted. You will probably have to change the BIOS boot order on most machines you plug it into, but as long as it isn't password protected that's okay. Go, enjoy the comforts of home, wherever you are!

Okay, so you've registered your nickname with freenode, but everytime you log in through Pidgin it asks you to identify.

Instead of typing /msg nickserv identify your_password every single time, add NickServ as a buddy, and set up a buddy pounce.

- Right-click buddy, select 'Add Buddy Pounce'
- Select Pounce when ... Signs on.
- Select Action ... Send a message.
- Type 'identify your_password' in the text box.
- Select Options ... Recurring.
- Then press Add to save and exit the dialog.

Now when you sign in Pidgin will identify for you. Much better.