This circuit is a MIDI interface between drum pads and computer or hardware 

 sequencer. Using this circuit you can hit pads with drumsticks and store the 

 MIDI data in real time.This circuit is based around the PIC16C84 microcontroller 

 which scans the inputs on RB0 to RB7 and when a high is detected the 

 software transmits the equivalent note-on ( and then the MIDI note-off after a 

 short delay) for the required drum sound on the MIDI output on RA0.