Learn to use the buttons in your stellaris launchpad microcontroller to read digital inputs.
Link to code:
http://allaboutee.com/2014/01/06/stel...
Stellaris LM4F120H5QR Microcontroller Data Sheet:
http://www.mouser.com/ds/2/405/lm4f12...
Stellaris LM4F120 LaunchPad Evaluation Board User Manual:
http://www.ti.com/lit/ug/spmu289c/spm...