for extra credit 1

Dependencies:   mbed

Changes

RevisionDateWhoCommit message
2:7eeefc3bbca4 2015-02-08 yifeng021 extra1 default tip
1:fb9ce7e54c8d 2015-02-05 yifeng021 extra credit1: buzzer
0:893e598b3e49 2015-01-30 yifeng021 Buzz feature added!