The laser follows a word:

After a simple elaboration of the coordinates sent to the PC:


Overlaying the image taken by the webcam with the one reconstructed the result is:



The system presents many limits, both physical and hardware:


These measures can improve the performances:


Although the performances obtained with this project can't be compared with those of a real graphic tablet, the result can still be considered acceptable for the creation of doodles and rough drawings, expecially because of the small cost of the components (30-40 €) and the reusability of the Raspberry Pi. Of course, like in real drawings, the results are greatly affected by the ability of the user: in the exemple above I wasn't able to properly follow the word writted on the background, so the result is not really great, but with more patience and a better hand it could have been really good.