Adapter I2C/SPI for alphanumeric LCD

Alphanumeric LCD modules are easy to pair with Arduino, but even in 4-bit mode they use too many valuable digital I/O pins. The solution could be connecting it with I2C or SPI protocol using an adapter (2 analog inputs for I2C or 4 digital for SPI).

Of course the standard LiquidCrystal library won't work with this adapter, so you have to use a modified by Adafruit version (available on GitHub).

About I2C/SPI adapter:

• assembly instructions http://www.ladyada.net/products/i2cspilcdbackpack/
• modified LiquidCrystal library on GitHub