This cool module gives your robot or project a simple display to communicate back to you with. It is assembled with headers already attached so you can start using it with breadboards and Arduino controllers without reaching for a soldering iron. You could use it to show arrows when a robot is moving or turning, emoticons for a robot pet, bar graphs for sensor indication, debugging info, or just doing a message. It is based on the MAX7219 controller chip in a DIP package. This chip only uses 3 IO pins, and multiple modules can be daisy chained together to create larger displays! There is example code to drive the module from an Arduino, and the chip is well documented.

Maxim MAX7219 datasheet.

Module operating voltage: 5V Module size: 5 cm in length X width 3.2 cm x 1.5 cm

Weight (kg): 0.021 4 holes for M3 screw mounting. Fully Assembled - soldering not required.