Communication

Use the Teensy board to fake Human Interface Device (HID) input. Human interface devices are recognized by your computer without need for drivers or custom software. They include computer mice, keyboards and joysticks. You can program the Teensy using arduino!!!

Sparkfun has a nice little module for logging up to three channels of sensor data for up to three hours and then spitting it out on command.

MIDI, the Musical Instrument Digital Interface, is a useful protocol for controlling synthesizers, sequencers, and other musical devices. MIDI devices are generally grouped in to two broad classes: controllers (i.e. devices that generate MIDI signals based on human actions) and synthesizers (including samplers, sequencers, and so forth). The latter take MIDI data in and make [...]

xbee is a wireless communication device from digi.com that uses ZigBee protocol. “ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4-2003 standard for wireless personal area networks (WPANs), such as wireless headphones connecting with cell phones via short-range radio. The technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs, such [...]

The simple thing xbee can do is to replace the serial connection wirelessly.
You can do this pretty much out of the box.
It is like replacing the USB cable of arduino (serial communication) to invisible cable (wireless).
Here is an example of how to set up serial wireless communication:
On Arduino side, the connection is following. Basically you [...]

There are many ways to do wireless communication. When developing wearable technology project, it tend to come in play. At the moment, xbee is our favorite, although there are many other ways to do wireless communication.

Sparkfun made a great comparison on wireless modules. 
Sometimes you do not need large data rate, or you need something that [...]

This post explores how to establish a communication between multiple xbee that are connected with sensors to one receiving Xbee that is connected with computer. Xbee 802.15.4 with chip antenna is used in this example.
For reading the Xbee input, I am using XBee API Library for Processing from Rob Faludi and Dan Shiftman

This example is applied to WIRELESS JOYSLIPPERS. For detail of the physical construction, [...]

This example explains how to send sensor input (analog) wirelessly to computer via xbee (Series 1 802.15.4) without using microcontrollers.
Step 1:
 You need to set up the AT command for both receiver and sender.
You can use X-CTU or some kind of terminal software,  Rob Faludi’s Xbee Terminal Max. I am using a small Max Patch made [...]

xbee can be connected directly like an invisible wire. You can set the matching pins as one of them as input (AI/DI) and the other as output (PO/DO).

To communicate with xbee from your computer, you need to make serial or USB/serial connection between your computer and Xbee.
There are some Xbee-USB dongles you can buy, such as XBee Explorer USB from Sparkfun or USB-XBEE-DONGLE-CARRIER from New Micros.
Also, here is a nice site that shows how to make your own USB-Xbee dongle (I think you [...]

How to upload firmwares on Xbee using Arduino board.