hardware

USB hubs are a thing I prefer to stock on, since I really often use these in my projects . Threrefore, just when I was running low on ‘em, I ordered a bunch in bulk from china. Took about a month, till our slowpoke-post delivered those.
Anyway, being pessimisticby default, I started by doing an lsusb -vv on the hub device:
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My home server has a long story. It all started with a Pentium 4, an old 20GB HDD and FreeBSD 6.2 … hell, I don’t even remember the exact year.
Anyway, after a few years, the hardware was finally put to rest, since it died and got resurrected thrice, I got an Intel Atom D410-based miniATX board, switched to linux, first debian, then agilia, then arch… Anyway, it used to be a nice server for personal needs, that crashed only on occasional HAD-effect, so it was… sufficient.
Now, the time has come to move on, to arm. The benefits were simple and straight:

  • 10W peak power consumption
  • Fully passive cooling
  • eMMC for the root partition
  • 4 cores!
  • Always a serial terminal, starting from uboot phase, so that I don’t have to carry a monitor to the closet where it is stationed.

I picked ODROID-X2 based around Exynos4212 Prime. ODROID-U2 looked worse, since had NAND soldered onboard. eMMC looked easier to replace. And the benchmarks said eMMC was faster.

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So, here go my adventures with this hardware.
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It’s been a while, since I’ve posted a anything  about this shiny toy of mine. This doesn’t mean I’m doing nothing about it. And I’m adding a hack every weekend or two. Unfortunately, this is definitely NOT the thing you can grab and start printing happily, as are most of the sub – 5k$ printers. ( Don’t believe the marketing BS!)

So far, I’ve added a better filament feed, a usb camera mount, a cooling fan, fixed the Z axis wobble… partly…

Well, last time I replaced the lead nut with a custom higher one, I had a very slight wobble remaining. This one was due to the fact that the centers of the Z axis rod and the motor shaft were not perfectly aligned. That was still a little bit too annoying, when it came to 0.1mm prints. lawsy recently made a fix in the firmware but adding another variable that needs experimental calibration certainly doesn’t fit what I wanted. Anyway, 5/16 rod also annoyed the hell out of me (I prefer metric stuff, that’s my religion, bear with it!), so I decided to make a mechanical fix first. And the idea was to throw away that crap, and place something better.
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I’m not a psychopath, I’m just very creative.
(c) Harry Potter and the Methods of Rationality

Taking part in competitions like “eurobot”, where you have to do some coding in extreme conditions, on/under a table, on the floor, etc. and a few other trips like that convinced me that I should definitely make something more of my cell phone. Something, that will help me out in this case.

So, we have:

  • A dumb brick called ‘HD7 Pro’ from china, with android 2.3.5. One and a half years old.
  • /dev/brains
  • A few hours of free time

What we want to get:

  • A portable server with lighttpd, ssh, git, etc
  • WiFi AP with local dns, internet tethering (if we’re not roaming!)

2013-03-18-00-19-06

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5/16 screw tap?
Just take this heresy to Mordor and drown in the lava of mount Doom!
And use only metric stuff we have a plenty right here.
(c) A salesman at the local hardware store

 

Okay, fixing Z axis wobble, take 2, the proper fix.These instructions are quite complex, so make sure you have all the instrument and skills required. Otherwise, go for simpler lawsy’s fix.
And take care not to kill yourself trying to do it.
It all took about 12 hours of experimenting to get it working properly + a week or so seeking out the 5/16 screw taps throughout the city hardware marketplaces.

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I finally managed to find a few spare minutes and make some serious progress on this port.

So, what’s new:

  • Rebased against the current openwrt trunk
  • Initial router name/model  stuff support via uboot env.
  • Now with stable 3.4 kernel from sunxi-3.4 branch. OpenWRT compiles kernel and working module packages
  • sun4i-specific modules like ahci, ir, i2c, etc. are now compiled and loaded by OpenWRT.
  • Instructions for building can be found at the github repo

wrt

 

Okay, this is the first solidoodle hack, and the simplest one.
solidoodle is a quite affordable 3d printer I got myself a few weeks ago. And the biggest problem it has – Z axis wobble. Quite bad even when printing at .35 mm layer hight. That was pretty bad, since it also made printing at .1 mm hight impossible, and some layers broke off easily.

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