Synopsis: The Arduino software comes with a built in library for interfacing with Liquid Crystal Displays (LCD). The LiquidCrystal library lets you drive a 4-bit or 8-bit parallel LCD display. This example shows how to wire and program an Arduino and a 16×2 4-bit LCD display (GDM1602K from SparkFun).

Arduino with Adafruit Protoshield and 4Bit LCD from Sparkfun

SparkFun carries the cheap (cost, not necessarily quality) GDM1602K 16×2 LCD display (16 characters on 2 lines) with an LED backlight. It has multiple color options (red/black, white/blue, etc.) and runs at 5V (they also have 3.3V versions under a different model number). You need 6 pins on the Arduino to write to the display using 4-bit mode.

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Synopsis: Example code for creating a CLI that interacts with an Arduino-based microcontroller. Useful for playing with pins, turning them on or off, etc., in real-time, using a terminal program.

This example demonstrates how to create a CLI for an Arduino-based microcontroller. Connect to the Arduino with a terminal application (PuTTY is a good one) to send the commands (the serial monitor included with Arduino is not a good choice for this). The LED on pin 13 turns HIGH and LOW in response to the commands.

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