Make: Volume 93

PROJECTS: Electronics Fun & Fundamentals

online). Each 8-bit burst can represent a letter

of the alphabet, or a numeral, or some other

symbol.

One laser maintains a steady, unending stream

of pulses as a clock signal. The second laser

sends an 8-bit character synchronized with the

clock. The third laser marks the beginning and

end of each character. Figure

O

shows this

concept, spelling out the word CAT. This is not so

different from the I

2

C serial communication used

by microcontrollers!

You would need a keyboard to type the

message, and a microcontroller to convert

keyboard scan codes to binary notation. But if

you add an alphanumeric display ...