Projects @ morgan.hk

Projects pages are back up

Morgan — Wed, 28 Oct 2009 04:17:01 +0000

The pages seemed to be down recently due to the fact that my host, Dreamhost, might have moved me to a new server. All my other domains seemed to be fine, so overall it was a smooth switch from kitkat to islander.
All services are back. Enjoy~

Blü server cluster

Morgan — Tue, 11 Aug 2009 02:35:16 +0000

No so long ago, we received a couple of computers from the SCM.IT team (thanks to Prof. Liu, Antony and Simon), 20 computers (with their keyboard/mouse/LCD friends) to be precise. While 3 of them have dead power supplies, the other ones are happy and running along.

This post will outline some of the things I have done so far.

Setting up the computers

Since the computers will all be connected together in a cluster, I needed to setup the computers and connect them together. This was definitvely not an easy task but, with a little time, i got them all up together. Physically at least.

[insert photo of cluster]

The process each computer underwent was the following (several computers were done in parallel):

Check power supply
Modify BIOS settings:
- Allow PXE
- Allow Wake on Lan
- Restart on power loss
- Wake up at 6.00 am
- boot from USB, then SATA
- Num. Lock
- Enable Hyperthreading
Partition HDD and install Ubuntu Linux 9.04
I considered originally installing Linux using PXE but then thought it would be faster just to boot all the computers with Ubuntu Jaunty on my USB key. (it was faster)

Install openssh-server on all the computers

sudo apt-get update && sudo apt-get -y install openssh-server && sudo reboot

Connect to the blü network

Setting up the network

Since we need to keep the costs down (the computers were lended to us for free), we also went the cheap route for the network. If we keep the “google” approach to the cluster, we should stick to cheap components that can easily be replaced in case of failure. Thus, the following networking tools were purchased:

D-Link DIR-300 router (on which i installed DD-WRT) @ $HK199
D-Link 16port 10/100 switch @ $HK230
300m of CAT5 cable
50 RJ45 plugs
crimping tool

The longest part of this process was, of course, making the cables.

Remote access

I had a look at which solution would be the best in order to control all the computers graphically without having to buy expensive KVM switches. My final decision went for running Xsessions over ssh. This would ensure minimal modifications to the system and security.

Other choices were X forwarding and VNC. I did not go for VNC because of security reasons and also because i had touble forcing it to launch before the gdm prompt. Similarly I did not go for X forarding because I had concerns about security.

To run Xsessions under windows one needs to install Xming and Xming-fonts. Then create a xml file with the following extension: .xlaunch and content:

replacing of course 192.168.0.1 by the client IP and gnome-session by the program you would like to launch

Final report

Morgan — Tue, 26 May 2009 09:28:50 +0000

final report2.pdf

Wiiflash issues with the Wiiolin

Morgan — Sun, 26 Apr 2009 11:07:19 +0000

So the Wiiolin is due on tueday and I still have to iron out many bugs. The main problem is the fact that the wiiflash server does not want to work anymore on my Windows7 machine that I plan to use for the presentation.

I have used different Bluetooth Dongles: Integrated HP, external no-name USB dongle
I hqve tried different Bluetooth Stacks: the MS7 default bluetooth stack, the Bluesoleil 6 stack and the Toshiba Stack and none of them seem to play nicely with Wiiflash.

After trying on my linux box that the wiimote was still functional using wmgui, I tried with my mac and it would simply not send any commands to the wiimote while it would still get the information from the wiimote, thus giving me only one-way comminication.

I have it finally working using a very early version. The current version of wiiflash is 4.5 and I will be using a un-numbered version (probably the first one) in console mode. It works very nicely.
my communication protocol has been implemented on the arduino side and I am trying now to get it to work properly on the Flex application I am building as a front-end.

So… what’s wrong?

Morgan — Wed, 22 Apr 2009 06:03:53 +0000

A well due update on the project.
Since I am too busy with FYP recently i have not had much time to concentrate on my final assignment.
So far done:

Violin with embedded wiimote, LEDs, amplifier and microphone.
Arduino with connection to LED and wiimote

So far failed:

Communication between wiimote and arduino
software

how to fix the failures:

communication:

I changed my method of connection and decided to use a more “analog” aproach. Instead of using the twi provided by the IC2 protocol of the wiimote, I will simply use commands to turn the LEDs of the wiimote on and off. This way i will send code to the arduino using a home-made protocol that goes as follow.

It will be a cyclic protocol based on 300ms delays between data transfers, a “begin” tag for syncronisation and a “data” tag on each 3bit packets defining if we are in the middle of a sequence or not.

Since i have 8 leds to turn on and off I will define the data as follows:

111 - begin
011 - turn on LED 1 and 2
011 - turn on LED 3 and 4
011 - turn on LED 5 and 6
011 - turn on LED 7 and 8

the first bit set to high will be only for the begin packet
the first bit set to low will be for all other packets
the second and third bits will be used for data. high turning on… low turning off.
trying this afternoon.