Hand Prosthesis

In relation to the previous post… There’s more impressive work. This is the limb from Touch Bionics in Scotland. BBC, do I need to say more… Unfortunatly the Youtube version is cut and I have not yet found the whole program on the internet. There are also some interesting user stories on Viddler.

Featured on BBC Breakfast:

Prosthetics progress

This was really cool! Nice prosthetics overview. Impressive project. Control is the problem and they have come slightly further than mentioned on CBS.

Power Consumption of Some Electronic Devices

Updated: More thourough investigations into power consumption shows that it is perhaps not quite as bad as it seems below. The meter used below seems to have quite a large error when there is a large difference in phase between voltage and current… So the figures below should probably be seen as wort case using a cos(phi) close to one, which is not always the case.

A friend of mine let me borrow his power meter under the condition that I posted the results here. So here we go. The meter does not have absolute accuracy, but I’d guess the values below are within a watt or so.

• Brodband Router (with phone connection) – Inteno (Bredbandsbolaget standard)
  On: ~5W
• NAS – WD MyBook World II 1TB
  Power adapter alone: 4W
  Turned off: 3+4=7W
  Sleeping: 8+4=12W
  Streaming music, network sharing: 12+4=16W
• Printer – Epson Stylus Photo R200
  Turned off: ~0 W
  On, no print job: 4W
• USB Hub 4 Ports – Deltaco UH-410 with separate power supply
  On: ~0W
• Wlan router – Apple Airport Extreme
  On: 14W
• Homeplug — Netgear HD Ethernet Adapter HDX101
  On: 7W (each)
• External har drive – old 2.5″ laptop drive connected to Airport
  Sleep: ~0W (power from USB hub)
• Computer – Apple Power Book 15 G4
  Sleep: ~5W
  Idle: ~25W
• Router/Music streamer – Apple Airport Express (APX)
  On, not streaming: ~2W
• Radio – Denon TU-225
  Off: ~0W
• Amplifier – Nad C350
  Off: ~0W
  On, not playing any music: ~31W
• DVD player – Pioneer DV-410V
  Off: ~2W
• “Power Saving” switching outlet from Clas Ohlson
  Always: 7W (Seems this is not quite true, cos(fi)=0.1 or so and the meter does not get that)
• Phone – Siemens Gigaset 3010 Micro
  Base station, not charging: ~4W

That’s it. That means that if I keep my home network and NAS up 24/7, the power consumption is at 40W in standby, not including the custom broadband router used for my internet connection and telephone. That’s probably another 10-15W. Counting on 50W and assuming a power cost of SEK1/kWh, it adds up to more than SEK1 each day. Yikes.

Matlab Simulink slow mouse click response

The wickedest thing… When enabling desktop effects on Ubuntu Intrepid Ibex, Matlab Simulink has serious difficulties in perceiving the mouse clicks.

Symptoms:
1. A single quick mouse click has no effect
2. Double clicks must be REALLY slow to have the desired effect
3. Add to this significant delays and generally very unresponsive behaviour

The remedy is to turn off desktop effects in the ubuntu desktop (System->Preferences->Appearance). The sad thing is that I really enjoyed those visual effects.

Perhaps desktop effects can be turned of for certain applications only? Well, well, back to work…

Change Default Language in kUbuntu 8.04 Hardy

It seems the system settings accessible through the kUbuntu GUI does not suffice to change the default system language, or at least it is not as intuitive as it should be. As this is the language used at the login screen and especially in the Konsole, it can be horribly annoying.

You can check your locale setting using

% locale

To fix it the hard way, just edit

/etc/default/locale

to you liking or use

update-locale

and reboot.

Apple Keychain Permission Problem and Solution

Suddenly I got a new error message and could not add any items to my keychain. The error message also mentions something on file access…

“An error has occurred. Unable to add an item to the current keychain.” or in swedish “Ett fel inträffade. Kunde inte lägga till ett objekt till den aktuella nyckelringen.”

The solution was nowhere to be found, but using the terminal, it can be fixed easily by setting the right permissions for the keychain. Somehow, it seems the permissions are wrong. I doubt they have changed, so most likely Apple changed something in Keychain access. But am I just guessing here…

$ cd Library/Keychains/
$ ls -l
total 232
-rw-r--r--  1 root  staff    27K  8 Dec 20:30 yourKeychainName.keychain
-rw-r--r--  1 yourUser   staff    86K 16 Jan 19:38 login.keychain
$ sudo chown yourUser yourKeychainName.keychain
Password:
$ ls -l
total 232
-rw-r--r--  1 yourUser staff    27K  8 Dec 20:30 yourKeychainName.keychain
-rw-r--r--  1 yourUser staff    86K 16 Jan 19:38 login.keychain

Now the keychain works as it should.

Selektiv perception

Man ser vad man vill se och inget annat. Ibland.

Jag vill ha mer jul…

Robots.net måste ha den bästa julklappslistan. Evah.

Sad Robot

It’s such a sad story you know…

Apple OSX (Leopard) Firewall DHCP problems

I get the classic “self-assigned IP address” (egentilldelad ip-adress) after reboot. This started occuring after I reset the SMU and has happened once before when my battery went, really, really, really dead. That time I got my computer running again, but it may have been Tiger back then…

You should be able finding the “deny configd” message in the log of your firewall. I do unfortunately not anymore get the annoying “allow configd to accept incoming connections” message at startup… 

At home I use an Airport Extreme base station. At work I connect to the office WLAN and get the same message in my firewall log, but I get a correct IP-address.

1. Searching Apple’s support pages for “deny configd” is interesting and I guess it won’t hurt resetting your firewall by throwing away com.apple.alf.plist (in the /Library/Preferences/ folder). (You will not find it using Spotlight as many of the systems libraries are excluded. Sigh…) This did not do it for me though.

2. The next suggestion is to add configd explicitly to the firewall rules. This can neither be done as easily os one would hope as Apple will not allow you to navigate to the path of configd. Sigh… So to do this, create a (soft) link to /usr/sbin/ on your desktop and drag that link to the “myplaces” in you finder window (file browser). Now you will be able to navigate to /usr/sbin/configd from the firewall settings.

3. The last hint is what actually got me up and running the last time. Apparently there are some kerberos magic involved in getting the IP-adress from the server. Following what is outlined here will help you reset the local KDC certificate (whatever that is…). This thread might also be a good read for further reading on the issue.

However, it is now messed up again, and I will post more here as soon as that is resolved.

4. This time I got quite upset and reset the kerberos-stuff (as outlined above) once more and also deleted (i.e. changed name on) the com.apple.network.identification.plist and com.apple.smb.server.plist (both located in /Library/Preferences/SystemConfiguration). The problem re-occured after an overnight sleep.

5. Ran the 10.5.5 combo update. Looking good sofar…

I also noticed this blogpost that is a little more brief