To recap, LCDuino is a marriage of an Ardunio Uno with an AdaFruit RGB LCD shield, but as a "backpack" board for the LCD module. The LCDuino main board is 80x36 mm - the same size as the board for the LCD module itself. The board houses an ATMega328 in a TQFP package along with an FTDI USB-to-serial adapter chip and an MCP23017 i2c GPIO chip to interface to the LCD. The board also has a micro USB connector (used for getting power from a PC and uploading sketches), along with a DIP-26 connector to connect a ribbon cable to whatever else you want to play with, and a DIP-14 to carry the button signals from the MCP23017 off to a button board.
The ribbon cable is intended to terminate in a 28 pin .3" DIP plug for easy attachment to a breadboard. You can either power the LCDuino through the ribbon cable or power the breadboard from the LCDuino via the USB connector (there is a 500 mA self-resetting fuse to protect your computer).
You can also, alternatively, connect the ribbon cable up to the LCDuino shield adapter, which includes a 2.1mm barrel connector for a 7-12v power input, which is regulated down to 5 volts and 3.3 volts to provide power for standard Arduino shields. Of course, you still get the i2c RGB LCD display along with whatever shields you want.
|JP1 is actually pins 17 and 18 on the RGB LCD, which provide the "green" and "blue" backlight control. The "K" pin is actually the red backlight.|
|JP2 and JP3 are actually extensions to the high digital and power connectors (like on an Uno rev 3), which add dedicated i2c pins and the IOREF pin.|
The LCDuino as a "quick kit" is $30, and the shield adapter (also as a "quick kit") is $20.