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Personal tools

FR as host on active hub

This is my latest artwork:

Mobile workplace.jpg

Mobile work-place ;) Freerunner beeing charged from a modified USB hub using 5 AA batteries.

Full keyboard, mouse and external HDD connected!

Internet access wia UMTS dongle.

A special holder places the FR into a reflection-free angle.

Note the TUX penguin, that I have manually glued on the 'Windows-Keys'!

I have bridged the output power supply of the USB slots in the USB hub back to the 'input' line (where the FR plugs in). With a manual switch I can turn on/off this power feed. This might be some good luck that the good piece didn't blow off - it's a 20EUR DLINK hub.

The USB gender changer (female/female) can be bought for example at the big 'C':
http://www.conrad.de/goto.php?artikel=974822

The power supply are 5 AA NiMH accus, which deliver around 6.5V when fully charged. This is about the same voltage the comes from the external AC/DC power plug.

SolderedHub1.jpg SolderedHub2.jpg

Note the single blue wire on the bottom right of the right image. This is all it needs. The rest is just fun like an additional switch with a LED to turn power-feed on and off and another Type-A USB slot, so that I don't need the genderchanger and the Type A/B converter any longer as one can see it in the topmost image.

ATTENTION:

After I have soldered the second USB connector (the black thick cable on the left image), the hub did not work any more on a regular PC, although it still worked on the FR. So my assumption is, that it is not broken, but maybe the USB signal reflects on the open-ended cable. I will invastigate further.

More images:

USBPipelineLong.jpg USBPipelineShort.jpg USBHubWithDisplay.jpg

From left to right:
Usual way to use the FR as a USB hub (you need 3 different adaptors)
'Short' way with self-soldered USB connector into the hub, which makes it unusable for PC's, though!
Integrated voltage meter in the USB hub, displaying either the HUB's own power supply voltage, or the voltage delivered from the FR to the hub, depending on the small switch that I have built in. LED indicating current direction.

Using alternate browsers

Midori is nice...but not a fully usable browser. And loading pages over cellphone network is pretty slow. Therefore I use a ssh tunnel to a X-server at home and look at it via vnc. (I don't explain how to set-up an ssh account through dyndns here...)

at home type:

vncserver :30 -depth 24 -geometry 1280x1024
DISPLAY=:30 firefox &

on the FR in a first shell:

 ssh -L5930:localhost:5930 myaddress.dyndns.org

and in a second shell:

vncviewer localhost:30

Adding swap space on mmc card

In SwapSpace is descriped how you add a swap file on filesystem. This seems somehow complicated to me. I wanted to use my microSD card for swapping (it doesn't matter if it gets broken after 2 million read/write accesses). Also, I don't want the mmc card formatted with VFAT anyway, so I made a new partitioning:

/dev/mmcblk0p1               1        5129      500075   82  Linux swap / Solaris
/dev/mmcblk0p2            5130       81820     7477372+  83  Linux

and added in /etc/fstab:

/dev/mmcblk0p1          swap                    swap    defaults        0 0

doing a

 mkswap /dev/mmcblk0p1

once and a reboot and we're done.

See what 'top' says: the internal 128MB memory is almost always completely exhausted, with just one or two applications running. With 512MB swap space I can use Midori, tangoGPS, several terminals, the settings pages and so on all at the same time.

Mem:    120856k total,   116364k used,     4492k free,      172k buffers
Swap:   500064k total,    67696k used,   432368k free,    71764k cached

Contact me

openmoko

at

edv-buero-lehner.de