<div dir="ltr">The following two equations would give the position of the dry erase marker relative to point A. (I may have mixed up my positive and negative directions somewhere, but you get the picture.)<br><div class="gmail_quote">
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div dir="ltr">
<br>d_Ax = (v_sound)sqrt(t_A^2 - t_B^2)<br>d_Ay = h - (v_s^2)(t_B^2 - t_A^2)/(2h)<br></div></blockquote><div><br>I just came up with this next idea as I was turning on the shower water. The x and y position can then be translated into screen coordinates (after calibration). This can then be passed through ReMoko to some other device. Combine this with a projector and you have yourself a nice smart board.<br>
<br>-Charles Pax<br><br>P.S. I'm thinking about all this because the high school where I teach physics gave me a $800 mimio device to aid a visually impaired student of mine. The problem is that the mimio device only works with Windows and OS X and I don't want to be limited in my operating system choices. i also think it would be cool to beat the system and do the same thing with $40 off-the-self components.<br>
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