The dryer Arduino

Out of sheer curiosity I decided to measure the temperature and humidity levels in the air being expelled from our tumbledryer.

So this little one was born :


(Click for larger)

I’s a Jeeduino mounted on top of a batterypack (with 3 * AA batteries) and a SHT11 sensor on a set of wires to allow me to insert it into the exhaust tube. In the end I decided to put the whole assembly inside the tube, where it wirelessly sends its measurements into the rest of the house automation system

Second superb meal – London

On Friday we were invited out to Kai in London – one of the very few Chinese restaurants in Europe with a (new) Michelin start.

The food was extremely good – and there was enough of it, with some very extragavant dishes on the menu, such as


which as you can see requires more planning for what to eat than I can ever see myself managing to do.

But if you want to taste what modern chinese cooking at it’s best can taste like – recommended.

Episodes: a Framework for Measuring Web Page Load Times

Measuring download speed of web pages is a big thing for me – and there are extremely few tools that can be used to reliably gather both the download time of individual pages once and twice (to simulate the effect of internal browser caches – and intermediate proxies) – and do this at regular intervals to find the effect of varying server load throughout the day.

Episodes seems like a good tool to solve part of this requirement :

Episodes: a Framework for Measuring
Web Page Load Times
Steve Souders
July 2008
Interest in web performance is growing rapidly. Web companies are trying to use speed as a distinguishing feature. At the same time, web pages have more content than ever before which makes for a slower page. Ajax helps reduce the number of roundtrips required for a web application, but today’s alternatives for measuring web performance don’t work well for Web 2.0 apps.
What’s needed is a way to measure web page load times that works for Web 2.0, is easy for web developers to adopt and maintain, can be leveraged by web metrics service providers, generates data usable by web development tools, and provides context to browsers so they can give better feedback to users about their experience.

[From Episodes: a Framework for Measuring Web Page Load Times]

Dynamic Demand – and it’s role in making the UK greener

Interesting concept – by measuring the frequency of your electric power supply you can see the health of the UK power grid, and in turn you can turn on or off your electricity usage to make sure you tend to use power when it’s mostly produced by “green” sources:

How balanced is the UK grid at the moment?

This meter is monitoring the power balance of the UK electricity grid. If the needle is too far to the left, it means more generation is needed to meet demand.

The meter actually shows the grid’s “frequency”, which is related to the speed of rotation of generators all over the country. When there is too little power available, the whole grid “slows down” and the needle moves to the left.

Why is this important?

It is important because it is possible to measure this signal from any power outlet in the country. This means that it is possible to design electrical appliances that know the current imbalance on the grid. This is what dynamic demand control is about.

[From Dynamic Demand]

One more test of full body scanners

One more opinion on full body scanners at airports:

Schneier on Security
A blog covering security and security technology.
« Web Security | Main | Transport Canada on its New Security Regulations »
January 22, 2010
German TV on the Failure of Full-Body Scanners
The video is worth watching, even if you don’t speak German. The scanner caught a subject’s cell phone and Swiss Army knife — and the microphone he was wearing — but missed all the components to make a bomb that he hid on his body. Admittedly, he only faced the scanner from the front and not from the side. But he also didn’t hide anything in a body cavity other than his mouth — I didn’t think about that one — he didn’t use low density or thinly sliced PETN, and he didn’t hide anything in his carry-on luggage.
Full-body scanners: they’re not just a dumb idea, they don’t actually work.

[From Schneier on Security: German TV on the Failure of Full-Body Scanners]

Arduino programmer for Arduino

Excellent – should possibly be used to keep a gang of Arduinos code synchronised.

Wow, that title is flamebait… but give us a chance to explain. [George] wrote some code for the Arduino that allows it to program another Arduino. You may be thinking to yourself “this has already been done”. In a way it has, with the AVR ISP programming shield. But once the code has been uploaded to the Arduino, you don’t need a computer to program the next chip. This concept turns an Arduino into an in-the-field programmer. Right now his code only programs the ATmega328 and it’s a little buggy, but the concept is solid. A fully functioning independent programmer is easy to image; [George] has laid the ground work, the AVR ISP programming firmware has proven this can work with several different chips, and if your AVR has an ATmega328 there should be plenty of room to store the code you plan to flash to the target microprocessors. It’s up to you to put all the pieces together.

[From Arduino programmer for Arduino]