Arduino board suggestions for a keyboard project

I'd like to build a touch surface keyboard lcars alike. What auduino board should i have to acquire to build it? thanks.

"lcars"
Do you have a link to what that is?

"LCARS" is the touch-screen interface use throughout the starship Enterprise in Star Trek: Next Generation.

Have you chosen the touchscreen hardware yet? Depending on the interface to the touchscreen you ma want a very small or a very capable Arduino.

LCARS yes, the star trek system. I do not choosen the surface yet. It could be a plastic or a wood surface with copper points to allow contact with fingers or to use the plastic sheet that comes inside of standard keyboards.

I recently looked at a very old touchscreen library and put it on my (lengthy) to-do list to update for modern versions of Arduino and to support different boards. I even purchased 2 different glass touchscreens which are sitting here in a box of hardware waiting to be tested on various libraries!

As for boards, nearly any can work. Most of the resistive touch screens need only 4 pins with A/D capability.

If you want it to act as a real keyboard to your computer, you should definitely get one of the boards with a native USB interface. Teensy (which my company makes) has been around the longest and is probably the most stable. Adafruit also has a board based on the same chip, using the beta-test Leonardo stuff in Arduino 1.0.

While it's possible to make Uno act as a USB keyboard by reprogramming the USB chip, doing that is a fiddly process. It also discards the ability to separately print to the serial monitor, so debugging is much hardware. But if you can live with only serial communication, or you don't need to send the data back to a computer, then Uno or any other serial-only board should work just fine.

When/if you do interface the touchscreen, will you please reply here? Or if you're looking for a library, post again and I'll see about updating that one I found if you'd like to beta test it on Arduino 1.0.

Thank you Paul. To avoid any confussion I want to emulate a touch surface I will not use a touchscreen glass though. I will post any advance or requirement.

What will you use then? Maybe the CapSense library?

CapSense seems to be a good option, thanks for the suggestion, it could be work with an Arduino One?

If you choose an Arduino that uses an atmega8u2 or atmega16u2 for its serial to USB interface then you can reprogram that to be an HID keyboard. Its not difficult, you just put the arduino into DFU mode by briefly connecting two pins together and then use flip (windows) or dfu-programmer (linux, OS X) to flash new firmware to the 8u2/16u2. I have HID firmware here on my blog: Arduino Hacking UNO Keyboard HID, also an example sketch for using that firmware.

The new UNO r3 has the atmega16u2 which triples the flash space available for the USB driver compared to the 8u2 (12KB vrs 4KB), so it has a lot more potential. I'd recommend that if you want an Arduino for the project. I'm working on combo firmware for it that will support both a normal serial device and an HID device at the same time which would save having to switch the firmware back to USB serial in order to load a sketch.