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16  Forum 2005-2010 (read only) / Development / Re: A breadboardable Arduino clone with onboard US on: April 12, 2008, 01:54:19 am
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
17  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: Mounting of Arduino boards?? on: June 11, 2008, 10:35:08 pm
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 smiley

Here is whole thing in its box

A view of the inside

A closeup of the meters
18  Forum 2005-2010 (read only) / Interfacing / Re: v-usb library and board type on: December 13, 2010, 09:44:24 am
I can _program_ all three boards ok.  The problem is that I'm trying to use the arduino itself as a usb device
19  Forum 2005-2010 (read only) / Interfacing / v-usb library and board type on: December 12, 2010, 11:29:55 pm
I was trying some development with the v-usb library from 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.
20  Forum 2005-2010 (read only) / Interfacing / Re: PS2 Keyboard Emulator on: July 24, 2009, 02:22:41 pm
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
21  Forum 2005-2010 (read only) / Interfacing / Re: PS2 Keyboard Emulator on: July 18, 2009, 06:26:53 pm
Thanks for doing the link
22  Forum 2005-2010 (read only) / Interfacing / Re: PS2 Keyboard Emulator on: July 18, 2009, 03:43:54 pm
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
23  Forum 2005-2010 (read only) / Interfacing / Re: internal pulldown resistors? on: March 16, 2008, 01:33:13 am
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.
24  Forum 2005-2010 (read only) / Interfacing / Re: PS/2 port issue on: May 14, 2010, 12:12:12 am
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?
25  Forum 2005-2010 (read only) / Interfacing / Re: PS2Keyboard library on: July 26, 2009, 10:58:56 am
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

26  Forum 2005-2010 (read only) / Interfacing / Re: Dual Temperature Sensing on: October 07, 2008, 08:35:57 pm
I have used the DS18B20 with the one wire library.  They read from -55c to 125c
27  Forum 2005-2010 (read only) / Interfacing / Re: Reading serial data from magnetic card on: April 16, 2008, 09:07:34 pm
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.
28  Forum 2005-2010 (read only) / Interfacing / Re: looking for meter to interface with arduino on: April 09, 2008, 05:56:25 pm
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
29  Forum 2005-2010 (read only) / Interfacing / Re: Rudimentary Resistance Meter on: March 28, 2008, 12:10:12 am
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
30  Forum 2005-2010 (read only) / Interfacing / Re: Analog vintage gauges - Controlling amperage? on: February 18, 2008, 08:28:21 pm
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
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