[update: Obsolete since modem swap]

I promised I would write about the new network topology I realised by using my brand new wireless router. I installed DD-WRT on my new linksys WRT54G2. Now I will show how to configure it, so you don’t need an extra switch in a common telenet configuration. First I will describe the old situation and explain why it is done that way. Next I will describe how I managed to get the same result, using just one device and a bit of configuration magic.

So what is the old situation?

Old situation with separate switch and router
Old situation with separate switch and router. The blue lines are COAX cable, the green one is scart/hdmi, the purple ones are UTP (network) cables.

This is how telenet installs it. They provide an extra hub, to split the connection between the digibox / digicorder and the internet connection. It is necessary for the digibox/digicorder to work, that it can get an external (telenet-internal) ip address from a dedicated range (10.169.*.*). If the hub or switch would be removed, and the digibox/digicorder plugged into the router, it would get a private ip (192.168.1.*), from the routers lan-dhcp range. This is because the usual configuration of cheap router, does not allow to the split its switch-interface between internal and external ranges. It has one fixed WAN (wide area network) port, and the other ports are for the private network.

The new situation

elimination of the hub via VLAN
elimination of the hub via VLAN

This is my current setup. It’s almost the same, but now without a separate device for giving the digibox/digicorder its dedicated external ip address. It is now done using some configuration magic.

I used one of the fixed internal network ports to form a WAN-switch. This can be done by configuring a VLAN where this interface, and the WAN port are combined, which leaves me with only 3 internal fixed network ports. This is enough for me. One for my fixed computer, one for my XBOX360, and I even have on left unused. My other computers are connected to my private network using Wifi.

This is how you configure it using DD-WRT: It is as easy as unchecking, and then checking another checkbox, and saving the settings. (rebooting the router if it doesn’t work the first time)

checking the checkboxes
checking the checkboxes

Click the image to get the full size.  The result is the same as if you would have the extra physical switch in between, only now, it is implemented as a “virtual” switch inside the router.

The advantage

You only need one device, where you used to have two. This saves a UTP cable, a wall-plug, the space to put the switch and lots of energy (= money). I have not calculated how much energy my old setup consumed, and now that the router has died, it is also no longer possible, but I guess that in this case one device consumes less energy than two. If someone has a kWh meter, I will gladly measure the energy consumption. We can than compare and calculate how long it takes before the new router has paid itself back.

What would be the impact if all telenet customers (that have internet + digital tv) changed their configuration? How much energy would be saved? I have always wondered how much energy the telenet customer side setup costs in terms of energy. There are so many boxes in my closet, all plugged in, are they really all necessary?

It’s saturday November 8th, 4:52 and I’m wide awake in bed. These are the times that really good (!?) ideas begin popping in my head. Today I felt the need to write some of them down.


A (web-) application to consolidate contact-information.

Yesterday evening, I was looking at how the Google Contacts API works. At that time I began to realize how usefull it would be to have some kind of application that consolidates contacts from different sources. The contacts I’m thinking about could come from outlook, gmail, yahoo, linked-in, netlog, facebook, plaxo, myspace, adressbook, windows live mail, you name it. I still had not registered the free domain name that comes with my new hosting, so – what the heck – I just registered consolidatr.net in true web 2.0 style, just in case I ever want to create such an application.

Batteries to reduce stand-by costs of appliances

What I was thinking – not yet done the math – is that it could be cost-effective to use of-the-shelve batteries (AA) that are quite powerful, yet cheap to reduce stand-by costs of appliances.

The Idea is that when a led and IR-receiver of for example a tv-set are to be powered, an amount of energy is wasted in the conversion from 220 alternating current (AC) to low voltage direct current (DC). So to cut that cost a fairly simple technique could be used. Let me elaborate.

Take a simple electronics circuit that houses some functionalities you want in your appliance. Power that circuit with a battery and add some logic to make sure the battery doesn’t completely drain.

For example, you want to be able to turn on and off your TV-set using the remote. What you need than is a IR-receiver. The TV-set would remain plugged in. A circuit with the receiver, a voltage meter, some logic and a relay would be needed.

When you turn off the TV – using the remote – it will go into a stand-by state. Lets take the power to support this state from a battery. The switching circuit would – in case enough power is available from the battery – completely cut power to the tv-set using a simple relay, from that time no more energy from the grid is consumed. When the battery is losing its charge, at a certain threshold, the circuit could restore power to the tv-set, such that the stand-by state is powered from the grid, and the battery is charged. (The battery would be charged when the tv is on too, of course)

A fail-over would be in place, such that in case no battery was present, or when the battery is worn out, your tv would still work, it would than just fall back to using the grid to power its stand-by state. The battery should have to be user-servicable.

Now for the math (this is just guessing…)

  • Lets suppose that you need 1 new batteries each year, because they will wear out eventually. 4 rechargable NiMH AA batteries of 2300 mAh can be found for a price as low as 4€. So 1€ per year.
  • The electronics are really simple, so in the full cost of a TV-set negligible, but lets add 10€, to be on the safe side. Let’s also suppose that you keep your TV-set for 5 years, so this costs 2€ per year.
  • Add some extra cost for charging the batteries, what you would normally not do. (I don’t really know how I would calculate this.)
  • Lets suppose that the batteries can power the stand-by state of a tv-set for 3 weeks on a single charge. (I don’t really know how much power it would consume, but I guess this estimate is rather conservative)
  • Lets suppose that the tv-set is used at least every other day, this would mean that the batteries would never become empty, and that all stand-by cost would be cut. The batteries would trickle-load, which would mean that the extra energy used to keep the battery charged, while watching tv, would be negligible. (This is kind of cheating, because the tv-set would consume a little more energy while it is on)
  • I just made all this up… If someone has real data, please comment!

Cost per year: 3€

Energy saved per year: according to http://www.standby-killer.nl/: 10€

this means 7€ saved per year. This doesn’t seam like much, but how many devices have you got, that are on stand-by?

If government would promote this, and everyone starts using this kind of technology (on more than just tv-sets) it would globally really make a difference.

It would even be better if it were possible to retrofit this kind of technology to existing devices!

Just invent a battery-enabled switchbox with a remote, put it between the TV-set and the grid and there you have it. It would cost a bit more, because the charging must now be done, either outside the box, or the switchbox would need a charging circuit.

The downside of using batteries of course is that they need to be recyclable, and I don’t know how well they are.

Another thought on low-voltage direct current

Ok, so how many appliances and devices in your home use low-voltage direct current? If I think about it: A lot. Every device that has an adaptor (separate power supply), that has some led’s or clock showing…

So, microwave, alarmclock, PC and peripherals, telenet-devices (cable modem, splitter, amplifier, digibox, networking equipment (Powerline Ethernet)), tv, dvd player, stereo, radio, battery chargers, mobile phone chargers, electric toothbrush, digital picture frame,…

My thought was: couldn’t it be cost-effective to have 1 central, high quality, efficient, powerfull “power supply” in the house, that all these other devices could get their DC from?

I am aware though that transporting low-voltage, potentially high current electricity over a distance is a problem due to resistance, but I’m talking in the scope of a home. I’m also aware that all these devices have different requirements qua voltage, current, what have you,… so some smart sockets would be needed.

I’m not going to do the math on this one, because I simply don’t have any data.

I’m going to try and get some sleep…