This Reprap Guru Smart Controller contains SD-Card reader, rotary encoder and 20 Character x 4 Line LCD display. You can connect it to your RAMPS 1.4 board using the "smart adapter" included. After connecting this panel to your RAMPS board, you don't need your PC to be connected to your 3D printer any more. All actions like calibration, axis movements can be done by just using the rotary encoder on the Smart Controller. Print your 3D designs without PC, just with a g-code file stored on the SD card.
OPTIONAL: The optional Printrbot Adapter allows the LCD Smart Controller to the connected to any Printrbot Simple, Play or PLUS. No modifications are required to firmware. Note that the SD Card on the LCD Smart Controller does NOT connect to the Printrbot. The internal SD Card on the Printrbot still needs to be used.
Here is an INSTRUCTABLE for the installation of the Printrbot Adapter.