The link doesn't work.

You don't need a resistor to hook up a servo.
In this presentation you can find instructions for connecting a servo to your arduino:
http://todbot.com/blog/wp-content/uploads/2006/10/arduino_spooky_projects_class3.pdf (page 22 following)

http://todbot.com/blog/spookyarduino/  <---- have a look at all the class notes. Very good stuff for beginners!

Well, since RS422 was mentioned I have to add RS485 which allows up to 1.2 kilometers of cable lenght at 100kbit/s (same as RS422 I think) and is quite common, too.

Does anyone have a link for how to build your own RS232 to RS4xx converter?

Have you seen this:
http://todbot.com/blog/2006/10/29/spooky-arduino-projects-4-and-musical-arduino/
http://todbot.com/blog/wp-content/uploads/2006/10/arduino_spooky_projects_class4.pdf

Whack the piezo to generate a number based on force of whack. Used for a MIDI drumkit.

Don't know how to do what you want to do, just wanted to point out that this 32 channel servo controller board was mentioned a few days ago.

http://www.lynxmotion.com/Product.aspx?productID=395&CategoryID=52
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1161642978

I'm sure there is an easier way, but maybe you can subtract 5V from your signal and amplify the resulting signal?

http://en.wikipedia.org/wiki/Operational_amplifier_applications#Differential_amplifier

Dunno about the software part of your question. I guess you need to code the 1 wire protocol by hand.

They are obviously teaching at universities or similar institutions and order them for their students and classes. I doubt anyone orders 35 Arduinos for themselves.

> Ouch, wonder why such a large markup over pcbeurope?

Don't complain. Usually it's the other way round, we Yurpeens usually have to pay twice as much for our imported gadgets as you do.  
I guess the price will go down once they sold their first lot.

The Ravezooka is a musical weapon that shoots a wide range of powerful "hardcore" sounds based on your target's distance from the instrument.

http://www.seseyann.com/ravezooka/ravezooka.html

Another Arduino project at Makezine:

6-pack - Arduino-based controller for live audio/video performances



"6-pack is an open-ended, highly customisable, and ultra-portable physical controller based on the Arduino board. 6-pack is an Arduino shield consisting of 6 linear potentiometer sliders that can be assigned to different variables in the user's preferred software. It can be used to control a wide array of audio/video applications, from software synthesizers to HDJ systems. All, with a minimal footprint (3,5" x 2,5") and on the cheap (just a fraction of the cost of an equivalent MIDI interface). The project is open source. Schematics and source code included."

http://www.display3000.com/html/screen-shots.html
http://www.shop-en.display3000.com/

> http://mitglied.lycos.de/polyxos/video.htm

Since Germany uses the PAL TV standard it might not work on NTSC equipment.

Maybe this is useful?

Oscilloscope using a microcontroller and a TV
http://www.nbb.cornell.edu/neurobio/land/PROJECTS/VideoScope/

Please upload the .hex file somewhere (Playground?) so others can get it too.

Has anyone tried harddrive motors? Will they work, too?