Ask HN: A way to turn any table into graphic tablet?

[Come-rad]

Hi, hackers. Artists all over the world use graphic tablets like Wacom to draw pictures. Is there a technical way to achieve this without touch enabled surface? One might think about some smart pen capable to track pressure, but I've not found any. Thanks.

[83a]

why not just add three microphones to your table and use a dump stick as your pencil. the sound waves are delayed proportional to the distance. by correlating the three signals you are able to get the distance between pencil and microphone. knowing the position of your three microphones you are able to calculate the position of the pencil.

i think there was a demo with piezo microphones on a wall or chipboard, but i'm not able to find it.

[Come-rad]

Are there any issues with other noises using this approach? And what's the level of preciseness if you remember.

[Come-rad]

Laser (as in the mouse), I guess, should work.