Welcome "Pinkpi", a Raspberry Pi Wireless AP 
Wow, that was easy: http://learn.adafruit.com/setting-up-a- ... t/overwiew

I didn't have to specify a driver in hostapd.conf because Raspbian 7 knows about the Wifi dongle already (RT5370) and although Ladyada suggests rebuilding hostapd the v1.0 that comes with the distro seems to work.

That USB dongle is a $9 Ebay-crap winmodem that I hope to get working. So I can take Pinkpi on trips to the backs of beyond that don't have intenetz, only dialup.

[UPDATE: There is no hope of getting a winmodem working on a Pi, unless you know how to write codecs. The various "linmodem" projects are highly dependent on the X86 architecture. If you want a winmodem really cheap, let me know, this one is useless. Pppd does work on a Pi, if you have a modem that talks serial. You can use a serial USB dongle, or, for the more adventurous, use the Pi GPIO pins for serial.

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Parted Is a Time Machine 
The rules for making new filesystems are only getting more complicated in RHEL/Centos 6. It's like going back in time to 1990...

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"Volname" replacement for Fedora 
The 'volname' command disappeared from Fedora a couple releases ago. Instead, use 'blkid':
volname=`/usr/sbin/blkid $DEV | sed -e 's/^.*://'`
eval $volname
echo $LABEL

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A Sub-$500 Haswell White Box 
I needed to replace my ancient single-core Athlon box running CentOS 5. It's been a trouper, but it's really slow now. CentOS 5 only has Firefox 17 in their repo, and that Firefox is too brain-damaged to use the
box's GPU card, so graphic-intensive apps like Google Maps and big bloated sites like Facebook just barely run.

The objective was to build a Haswell-based whitebox for less than $500, and I did it. I had to cut a few corners, like getting a cheap-ass motherboard, and an i5 instead of an i7. They still make motherboards with PS2 keyboard and mouse connectors! I thought those had gone long ago. So I can reuse my IBM Model M keyboard and my Wells Fargo mouse with the floating dog:


Intel Core i5-4670 Processor - Quad Core, 6MB L3 Cache, 3.4GHz, $215. To stay under $500 I had to settle for an i5 instead of an i7. I'd rather have a 2-core i7 than a 4-core i5, but this one will work just fine. (2 core i5's and i7's are not available in a desktop form factor anyway.) I don't overclock; this is fastest i5 available at this time and best of all it doesn't heat the room up at idle like the Athlon did.

MSI B85M-P33 Intel B85 Motherboard - MicroATX, LGA 1150, Intel B85 Chipset, $65. This is a really cheap motherboard but I don't need anything fancy. It has "Military Class 4 Technology", "Dark Choke", and "Solid Cap!" W00t.

Seagate Barracuda 1TB Hard Drive, 7200 RPM, 64MB cache, $70. A disk is a disk is a disk, although 64MB cache is better than 32GB. 7200 RPM is perfectly fine for a home system, more RPMs will just generate more heat and fail sooner. I am just astonished how disks just get cheaper and cheaper.

LG Electronics 24X SATA DVD+-R, $18. You need one for backups.

Patriot Viper Xtreme 8GB DIMM, DDR3, 1600MHz, PC3-12800, $85. Cost more than the mobo! You need at least 4GB to do anything, 8GB is better. Running a basic KDE desktop seems to use about 2 to 3GB. You might need 16GB if you do a lot of industrial scale compiling or virtualization. With 8 I can do some basic experimentation with KVM, Xen, etc.

Power supply and case: Reused from previous projects. The power supply is a 300W with the old ATX-1 20-pin P1 and 4-pin P2 but works fine for the modest load of my modest configuration, which should be pulling no more than 120W. If you do this make sure your mobo has a P2 connection and watch your power budget.

$2 for a PATA to SATA power adapter. 2 SATA data csbles came with the mobo.

Keyboard and Mouse: See above. (My model M is really a 90s vintage Lexmark Model M, sorry.)

Some gotchas:

VMware ESXi would not load on this mobo, the Realtek 8111B ethernet was not supported. Centos 6 had some problems with the 8111B but Realtek has the latest driver online and it's easy to install. Fedora 19 works fine with the 8111B out of the box.

The Haswell CPU series is so new that the i5 GPU isn't fully supported by the Centos 6 i915 driver. (It works, but you can't adjust gamma, which makes it fairly useless.) The i915 driver in Fedora 19 is OK, though. So I'm a born again Fedora user.

The MacAlly USB mouse I've been using for years doesn't work with either Fedora or CentOS and this mobo. Whatever, it's a dumpster-dived mouse. Sooner or later, I'll get a new freebie at a trade show or find one in the trash. Only suckers pay for mice.

The mobo BIOS and lm_sensors report 10 deg C different temps for the CPU. The CPU heat sink is not even sensibly warm, so I don't care too much about this. The BIOS says the fan is turning at only 1700 RPM when idle - so this PC is really quiet. Hoo-ray.

The mobo's fan and case temp sensors are not detected by lm_sensors. Not a problem.

The fan was bad in the CPU cooler Intel shipped with the CPU. With typical excellent Intel service, support didn't ask any dumb questions and they replaced it lickety split and with zero hassle.

Aaarrgh, fonts! Fonts suck AGAIN. Nothing seems to look quite right. It took me a while to get them right on the old box, too (see my previous entries.) Part of the problem is that Firefox still does its own rendering and hinting seems to be broken. Chrome is even worse, since you can't micro-manage the font and DPI settings like you can in Firefox. KDE and its apps, on the other hand, seem to be OK. Like all open-source things, this PC is a work in progress. Forward...

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Welcome "Greenpi", a Raspberry Pi Airplay adapter for the stereo 
I did something useful and computer-related for the house! Raspberry Pi-based Airplay adapter. Costs a little more than a used Airport, but less than a new one:

$40 - Pi
$15 - Wifi dongle
$6 - case
$? - 5V regulated wall wart (dumpster dived)

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A 32 bit font for the Seeed 64x128 OLED display 

Download the .ino file (as text) here

The array of chars was generated by:

1) Creating a GIMP image 32 pixels high, by number of chars X 20 pixels wide, with each of the ASCII characters in a 20-pixel wide cell starting at the left. Since the font is mono-spaced, they were just typed in, 0123456789....etc.

2) The image was exported in PGM ASCII format ("Netpbm PGM image text") since that's easy to read. The head of the file looks like this:
# CREATOR: The GIMP's PNM Filter Version 1.0
900 32

Download it here and save it as a .pgm file if you want to see what it looks like in GIMP.

3) The PGM file was converted to a C array-of-arrays-of-arrays with this python script. Since the font is mono-spaced, character boundaries in the width dimension fall every 20 pixels. The script converts the PGM file, which is a row-wise bit for bit sequence of 8 bit pixels 32 rows high, into an [nchars][4][20] array of unsigned chars.

4) You can cut and paste the data into your sketch, or put it in a .h file in the same directory as the SeeedOLED .h and .cpp files to #include it.

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