The project was born with the purpose of
replacing a graphic tablet, which is too expensive, with a much cheaper
system that can produce similar performances. The following parts were
needed: an hardware in which the code is placed and executed, a
comunication system to exchange data between the hardware and a PC, and
a device able to capture some kind of signal generated by a freehand
drawing. For the harware I used a Raspberry Pi, because it's more
powerful that an Arduino, and graphic elaboration is demanding in terms
of computing capacity. For the comunication system I used the simplest
way: a null-modem connection that exploit the serial ports of both the
Raspberry Pi and the PC. Unfortunately Windows doesn't allows the PC to
receive serial data and
elaborate them at once: you have to use a serial terminal
emulator, save the data and then elaborate. Since for this project I
used my own PC, which uses a Windows operating system, and I didn't
have another one with Linux I decided to be content with this solution.
Finally, I chose light to be the signal and so I used a laser pointer
to draw and a webcam to capture the drawings.
Paolo Sist, 2015
