Acronyms used here:

SI/OP "Simple Input/Output Project"
I/O "Input/Output"
LPT "Line Printer Terminal"
PCB "Printed Circuit Board"
LDR "Light Dependent Resistor
LED "Light Emitting Diode"
USB "Universal Serial Bus"
RC "Remote Control"
PWM "Pulse-Width Modulation"
D/L "Down Load"
OSHW "Open Source Hardware"