I like it, and I would buy one except that it uses a resonator rather than a crystal.  I hate that I have a decimillia tied up in my clock, but pretty much all of the cheaper boards won't work because of they use resonators

Here is a project I did that is mounted in a box.  This is a 3 meter analog clock.  The box is a wooden box my wife found at a craft store.  It looks nice enough that my wife let me put in in the front hallway

Here is whole thing in its box


A view of the inside


A closeup of the meters

I can _program_ all three boards ok.  The problem is that I'm trying to use the arduino itself as a usb device

I was trying some development with the v-usb library from rancidbacon.com and I noticed something odd.  If I download the program onto my decimillia, it works ok, but trying to use it on an rbbb or an arduweenie, it does not work (and by not work, I mean that my syslog shows a usb device trying to connect, but it never gets any thing from it).  The only thing I can think of is that the decimillia has a crystal and the other two boards use a resonator.  Do any of yall have any experience with this?  I would rather use one of my cheap boards for this.

Very interesting! I have also made such a library, and it's quite similar to yours. However, I've had some timing-issues, especially when I try to emulate both a mouse and a keyboard at the same time. Have you tried this with your library? I will definitely look into this later today, as it might solve some problems I've been struggling with for weeks.

I have used it as a mouse and a  keyboard but never both at once

Thanks for doing the link

Ok I have uploaded to the playground a library that implements the device side of the ps/2 protocol.  I used it in a couple projects, including a sun type 5 to ps/2 interface.  Also the ps/2 port on the computer can provide plenty of power to drive the arduino

If you are hooking up a switch of some kind, you can eaily make use of the internal pull up resistor.  Usually we use a switch to turn on the electricity.  You push the button and the line goes high.  and you would need a pull down resistor to tie the input low.  But we also make the electricity go the other way.  You use the pull up resistor to tie the input high.  You hook one end of the switch to the input and the other end to ground, then when you push the switch the input goes low.  Then in your software you look for the input to go low when the button is pushed versus high.

which ps/2 library are you using?  Are you using the one from the playground?

I am guessing that the problem is that the keyboard start up is not being done right.

can you post your code?

Personally, I would much rather have the Arduino EMULATE a PS2 keyboard versus having one attached to it.  I have a hard time convincing myself why I would want to attach a keyboard to an Arduino...

Look at this thread
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1247772275

I have used the DS18B20 with the one wire library.  They read from -55c to 125c

The track 2 data is 5 bits per character.  There are the digits 0-9, a start and end sentenel, and a separator character (which is used to mark the end of the pan).  

Personally I use ps/2 or usb hid card readers, though.

It is not very difficult to interface an amp meter to the arduino using the pwm output.  but you will need to use a very low current one (like around 1-10mA) as the arduino can only source 40mA on an output pin.  I did this to make an analog clock

The resistor by itself does not change the voltage, only by looking at the whole circuit can you tell what the voltage drop is.  There is a resistance in the analog input that you have to consider.

This is more or less what the circuit you are describing will look like
 
            A/D converter
       unknown    |      100Mohm
+5  ----^^^^^-----+----^^^^^^------
                                  |
                                 ---
                                  -

According to the atmega168 datasheet the input resistance on the analog input is 100Mohm.  So the input acts like there is a 100Mohm resistor between the a/d converter and ground.  if you have a 100Kohm resistor with on end connected to the analog input and the other to +5 then the voltage at the input will be 4.999 volts.  if you use a 1Kohm resistor then it will be 4.99999 volts.  That wont give you much range at all on your reading.

by using your unknown resistance as part of a voltage divider you will get a wider range of readings.  if you want to read between 1K-10K ohm, put a 4 k resistor in series with it


            Arduino input
       unknown    |     4 kohm
+5  ----^^^^^-----+----^^^^^^------
                                  |
                                 ---
                                  -


This will give a range of voltages between 4V and 1.43V.  Without the divider you would get a range 4.99999V to 4.9999V.  The divider is a much better solution

The output pins on the arduino can only supply up to 40mA of current.  So there is no way to directly drive those meters.  You will have to use a transistor of some sort to allow the arduino to control that much current.  You would be better off if you can find meters that work down in the mili-amp range