Ethernet over mains power lines

July 26th, 2010

I’ve been using a really clever device for the last few years that a lot of people seem to be unaware exists. It’s an ethernet over powerlines adapter – one such example is the Devolo dLAN. In a nutshell, you plug it into the mains, and connect the Ethernet socket to your network device. You can then plug as many others as you like to various other powerpoints and extend your network wherever the power stretches. Devolo do ones that run up to 200mbit. It’s a theoretical maximum, although I’ve got 177mbit before which is impressive. It has a couple of downsides:

1. It won’t traverse 3 phase power. I’ve tried it, and I’ve ended up with a very weak/nonexistant signal which is probably more inductance than anything else.
2. Obviously it doesn’t handle bad cables well – it doesn’t much like extension cables either.
3. Different circuits work about as well as 3 phase power, the only signal you will get is probably inductance between the two circuits.

Some advantages:
1. It travels pretty far. I’ve had over 150mbit between adapters at opposite ends of the house.
2. No new cabling
3. Fully supports standard Ethernet so all network protocols will work just fine over it.
4. I love it

For anyone running a home or office network and not fortunate to have Ethernet points cabled in, I strongly recommend these devices, you’ll never know the difference.

The Robot: Hardware List, Wheel Plan, More Ideas, Steps to launch

October 12th, 2008

Thanks to some further thought and some great comments and suggestions, I’ve got a clearer idea of what I’d like to build, and I’ve devised a preliminary hardware list. I’ve divided this into various categories to help planning and ordering.

Hardware
My bad wheel plan mockup for 4 wheels and omnidirectional movement:

Base Layout

Base Layout

Please excuse the awful graphics

The base layout should be as follows. The diamond shape is a very thin metal plate which will have the motors and motor casing attached. The metal plate will be at the very bottom of the device. The square (overlayed) will be the acetate base of the unit, and build up to form the base “box”.

I’d like the motor’s to be simple 6-9v, 10W max. motors

Each motor will be held on it’s own bracket and will not be connected via an axle. Each motor will require independant control via a motor controller. The motor controller will be required to convert digital input to variable voltage (5v/7v/9v?) output. 4 speed (4.5v/6v/7.5v/9v>) would also be fine.
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PHP, MySQL, Apache2 install HOWTO on Debian

October 7th, 2008

Setting up a PHP/MySQL/Apache2 environment on Debian is really easy, and as a PHP MySQL Developer, it’s kinda important! I’ll walk through a quick Debian lamp install howto and optimization process. I’ve optimized it for a 1.5Gb to 2GB RAM machine with reasonable load.

apt-get install apache2 php5 mysql-server-5.0 mysql-client-5.0 libapache2-mod-php5 php5-mysql php5-curl php5-cli php5-dev make gcc libc6-dev automakemysqladmin password 'NEWPASSWORD'

Now download eaccelerator from http://eaccelerator.net
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APNIC Box – Linux on a Mikrotik 532a, Part 3 – Installing Debian, Prebuilt Disk Image

October 5th, 2008

Follow on from 01 Oct 08 APNIC Box – Linux on a Mikrotik 532a, Part 2

The device runs a 2.4.30 kernel on a debian woody (mipsel) environment. If anyone can contribute anything for 2.6.x and debian etch, that would be great.

Installation instructions:

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APNIC Box – Linux on a Mikrotik 532a, Part 2 – Hardware Modifications

October 1st, 2008

Follow on from 01 Oct 08 APNIC Box – Linux on a Mikrotik 532a, Part 1

Custom Hardware Modifications

Here’s a labelled image of the inside of the device. You can also look towards the bottom left of the image for my simple solder modifications. Enlarge the image to see the labels.

APNIC Box Image 2

APNIC Box Image 2

1. External 2.4GHz/5GHz antenna. Same on opposite side.
2. 5V solder point
3. 5V connector for miniPCI USB card
4. 2x 2USB Headers. 1 Header in use providing 2x USB interfaces, one to regular host connector for mass storage or other usb connection. Other port for picoLCD on top
5. 512MB CF card
6. miniPCI USB controller

On the underside of the board there is a single miniPCI socket which houses an Atheros 5212 802.11a/b/g miniPCI card. It has two antenna outputs which run under the board and two the two external antennae. I haven’t taken a picture of this but if anyone really wants to see it, I will power down the device, get a picture of it and post it here.

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APNIC Box – Linux on a Mikrotik 532a, Part 1 – The Device

October 1st, 2008

I put this device together for fun sometime around the start of 2007. The ideas that spawned this was using OpenWRT on a Linksys WRT54G access point. A surprisingly powerful and full linux distro with all kinds of advanced capabilities running on a Linksys wireless router which I’d previously thought to be a reasonably dumb device with computing power more comparable to a calculator than a PC. The project opened my eyes to embedded devices, and I wondered what device base I should start with. To cut a long story short and for reasons that I can’t even remember anymore I came across the Mikrotik Routerboard 532A and decided that I should start with that.

Conception

APNIC Box Image 1

APNIC Box Image 1

Here’s a picture of the device from the outside with some labels, view the full image to see them.

1. Status LEDs. Blue at the bottom left shows it’s on, orange at the top right shows that there’s wifi activity.
2. Ethernet (eth0)
3. Standard Serial Console (57600, 8 N 1)
4. Ethernet (eth1)
5. Ethernet (eth2)

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Playing poker on Linux

October 1st, 2008

Linux is always gaining popularity on the desktop. Playing poker on Linux isn’t that hard and you’ve got a few options:

1. Find something web or flash based. Poker Room, Euro Poker and Hollywood Poker are a few examples of sites that offer that.

2. Java is a cross platform SDK. Absolute Poker, Party Poker, Poker Room, and quite a few others offer Java play.

3. Wine. I managed to get my favorite poker site Titan Poker working perfectly in Wine. Here are instructions for debian based systems:

apt-get install wine
wget <location>/setup.exe
wine ./setup.exe

It’s that easy! If you get a regsvr32 error during setup, it is safe to ignore it.

Double click ‘Titan Poker’ which will now have appeared on in ~/Desktop/Titan Poker

It works well, graphic and game quality is the same as Windows, sound also works with the right Wine configuration.