3 ms·
If you knew the position of the sensors, you could probably calculate a position from audio/vibration delays. You could make a kit for converting a normal white
by snprbob86 17y ago
If you knew the position of the sensors, you could probably calculate a position from audio/vibration delays. You could make a kit for converting a normal whiteboard into a recording surface.
Simply place sensors on the board corners and tell the software about their placement and the dimensions of your board. You need three sensors to do a proper triangulation, but you only need two if you know the sensors are in corners. With only two corner sensors, one of the two possible locations would be off the board, so you could throw that point out. If you can reliably sense whiteboard marker and eraser sounds, you could reliably "save" the whiteboard state.
- nvoorhies 17y agoWouldn't the delay between 2 sensors only give 1 delay, and thus one dimension? I don't follow how placing them on the corners makes this work.
- snprbob86 17y agoD'oh! Sorry, you are correct. I was thinking you'd get two distances to point of contact, but you actually get relative distance of the point of contact with respect to the sensors. You are correct, you would need three sensors.
- 10ren 17y agoI was thinking you could use volume, which would work with 2 sensors as you describe, but I like the idea of delay as it's probably more accurate.
- jodrellblank 17y agoThat idea kind of exists - a block with sensors sits atop the whiteboard and the pen is in a small holder. The sensors (I think they were IR or Ultrasound rather than sound) track the pen and have a serial link to a PC. Last I saw them in person was 8-10 years ago, though.