Power down the BeagleBone Black using the on board power button

The beaglebone black board has a power button next to the RJ45 ethernet connector. Pressing that button can get the board to cleanly shutdown.

First install acpid:

root@beagle1:/home/james# apt-get install acpid

Now test the shutdown. Press the Power button:

root@beagle1:/home/james#
Broadcast message from root@beagle1 (Fri Sep 27 01:13:49 2013):

Power button pressed
The system is going down for system halt NOW!
Connection to 192.168.1.116 closed by remote host.
Connection to 192.168.1.116 closed.

Installed system was Debian 7.1

james@beagle1:~$ more /etc/debian_version 
7.1
james@beagle1:~$ uname -a
Linux beagle1 3.8.13-bone26 #1 SMP Fri Aug 16 20:56:24 UTC 2013 armv7l GNU/Linux

Enable UART5 on beagle bone running debian

First mount debugfs:
mount -t debugfs none /sys/kernel/debug

Enable UART5:
echo 24 > /sys/kernel/debug/omap_mux/lcd_data9
echo 4 > /sys/kernel/debug/omap_mux/lcd_data8

Hardware Pins:
P8: 37 UART5_TXD
P8: 38 UART5_RXD

Device to access:
/dev/ttyO5

References:
http://www.jerome-bernard.com/blog/2012/06/04/beaglebone-serial-ports-and-xbees/

Debian Linux on beaglebone notes

Purchased beaglebone from digikey
http://www.digikey.co.nz/product-detail/en/BB-BONE-000/BB-BONE-000-ND/2765688

Added DVI audio cape
http://www.digikey.co.nz/product-detail/en/BB-BONE-DVID-02/BB-BONE-DVID-02-ND/3503684

Installed Debian Linux "Wheezy":
http://elinux.org/BeagleBoardDebian
http://elinux.org/BeagleBoardDebian#Debian_Wheezy_snapshot

Update system:
apt-get update; apt-get upgrade; etc

To load the modules for the audio cape:

sudo vi /etc/modules

at the end, add the lines:

snd_soc_davinci_mcasp
snd_soc_davinci
snd_soc_evm
snd_soc_tlv320aic3x

Power

With DVI audio cape attached, the device would often shutdown when powered over USB.  A separate +5 V DC 2 Amp power supply solves this problem.

GeographicLib

http://geographiclib.sourceforge.net/html/index.html

Installing more memory into a Lenovo Edge E320 laptop

Installation

A quick step by step guide to upgrading the memory on a Lenovo ThinkPad Edge E320 laptop. First step is to completely shutdown the laptop, flip it over upside down and remove the battery. Next remove the access panel from the bottom of the laptop. It's held in place by three screws.

Remove the three screws and the lift the large access panel off.

The laptop has two memory slots and ships with one 4 GB memory module installed.

We'll install another 4 GB module to give us a total of 8 GB of memory. The extra module will also mean that the laptop will go from a single to dual channel memory configuration which should give us a nice performance boost. The memory module I installed was a Kingston KTL-TP3B/4G.

The new memory module fits into the top most slot. Slide the module into the slot and then apply gentle downward pressure until the top and bottom metal clips engage to hold the module in place.

Replace the access panel, securing it back in place with the three screws. Re-install the battery and reboot.

Performance

Once the computer has rebooted, bring up the system properties dialog. This will indicate that you now have 8 GB of installed memory and that the Windows Experience Index needs to be updated.

"Refresh Now" will refresh the Memory (RAM) subscore

The Memory subscore increases from 5.9 to 7.3

If you "Re-run the assessment" you'll also see a boost to the Graphics subscores since the integrated graphics controller in this laptop uses the same (faster) memory.

Overall the Windows Experience Index has increased from 4.9 to 5.8. A nice improvement and the laptop is definitely a little faster to use on a day to day basis.

Combined THEMIS and ground-based observations of a pair of substorm-associated electron precipitation events

Combined THEMIS and ground-based observations of a pair of substorm-associated electron precipitation events

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117, A02313, 12 PP., 2012
doi:10.1029/2011JA016933

Key Points

• Combined instrument observations of substorms
• Determination of the flux and spectrum of electron precipitation during substorm
• Observations of substorm precipitation characteristics and evolution

Mark A. Clilverd

British Antarctic Survey, Cambridge, UK

Craig J. Rodger

Department of Physics, University of Otago, Dunedin, New Zealand

I. Jonathan Rae

Department of Physics, University of Alberta, Edmonton, Canada

James B. Brundell

Department of Physics, University of Otago, Dunedin, New Zealand

Neil R. Thomson

Department of Physics, University of Otago, Dunedin, New Zealand

Neil Cobbett

British Antarctic Survey, Cambridge, UK

Pekka T. Verronen

Finnish Meteorological Institute, Helsinki, Finland

Frederick W. Menk

University of Newcastle, Callaghan, Australia

Using ground-based subionospheric radio wave propagation data from two very low frequency (VLF) receiver sites, riometer absorption data, and THEMIS satellite observations, we examine in detail energetic electron precipitation (EEP) characteristics associated with two substorm precipitation events that occurred on 28 May 2010. In an advance on the analysis undertaken by Clilverd et al. (2008), we use phase observations of VLF radio wave signals to describe substorm-driven EEP characteristics more accurately than before. Using a >30 keV electron precipitation flux of 5.6 × 10⁷el. cm⁻² sr⁻¹ s⁻¹ and a spectral gradient consistent with that observed by THEMIS, it was possible to accurately reproduce the peak observed riometer absorption at Macquarie Island (L = 5.4) and the associated NWC radio wave phase change observed at Casey, Antarctica, during the second, larger substorm. The flux levels were near to 80% of the peak fluxes observed in a similar substorm as studied by Clilverd et al. (2008). During the initial stages of the second substorm, a latitude region of 5 < L < 9 was affected by electron precipitation. Both substorms showed expansion of the precipitation region to 4 < L < 12 more than 30 min after the injection. While both substorms occurred at similar local times, with electron precipitation injections into approximately the same geographical region, the second expanded in an eastward longitude more slowly, suggesting the involvement of lower-energy electron precipitation. Each substorm region expanded westward at a rate slower than that exhibited eastward. This study shows that it is possible to successfully combine these multi-instrument observations to investigate the characteristics of substorms.

Sun fish

Lunar Eclipse 2011

The skies were clear for this morning's total lunar eclipse. I took the following photos using a Nikon D40 with a 105 mm lens handheld. 

Max's Gallipoli blog

My son Max has just created his first blog! It's all about the First World War battle of Gallipoli.

The devil is in the details

I'm not sure why but I quite like looking out for potential public stuff ups of a slightly amusing nature. I spotted this one out of my office window. (To be fair I think they just had the sign upside down so that they could attached some mounting feet.)

ISS and Shuttle flyby

I photographed the International Space Station and the STS-118 as they orbited over Dunedin at around 6:30 am on the 21st August. The ISS is the brighter object. Photo details: Canon A530. 15 second exposure.

Comet McNaught

Something's not right alright

I nearly drove onto the footpath when I spotted this recently painted road marking!

My broken leg

Doctor told me I had a screw loose!
This is an xray of my right tibia and fibula taken last year. Was hit by a car whilst riding bicycle. Broke leg and both left and right radius bones. Doctors removed the loose screw - just got the rod and the two screws just below my knee now.