Normally driving an LCD requires seven connections to pins on the display, but by using a shift register, [Phillip Warner] at Arduino Playground was able to drive an LCD using only 3 wires.

To link a standard 16×2 LCD directly with the microcontroller, for instance Arduino, you would need atleast 6 I/O pins to talk to the LCD. However, if you use an LCD module with I2C interface, you ...

[Tobie’s] part of the hack is to use an Arduino and a few buttons as the controller. It’s easy to set up and we think the breadboarded controller approximates the size and weight of an LCD ...