This is a very popular lcd keypad shield for Arduino and other variants. it includes a 2x16 character lcd display and six momentary push buttons. pins 4, 5, 6, 7, 8, 9 and 10 are used to interface with the lcd. just one analog pin 0 is used to read the five pushbuttons. the lcd shield supports contrast adjustment and back-light on/off functions and has an led to indicate power on. it also breaks out five analog pins with dfrobot color code for easy analog sensor plugging and display. This design is great since it easily lets you connect sensors to the rest of the pins, or use it for monitoring or menu selection with the push buttons even for gaming. often project applications require testing or debugging. displaying information right away is helpful on most occasions when a computer is not at reach. if you are planning to build something not attached to a computer and you need to check what's going on when you place it on position, this addition will prove very valuable to make sure the program is running well. The used lcd pins are not exposed on top side of the board leaving only the unused ones. this eliminates conflicts with the lcd. this design includes a apc / Bluetooth v3 socket to enable data transmission with your robot.