This page is next level of Virtual Touch Screen project.
First things is a distance, for virtual touch screen its less than 3 m, because the reflective area is too small. For radar (or sonar) its different, and the bigger size of object the stronger echo. Approximated range of detection the object as big as a wall, 30 meters.
Technically, there are two hardware parts were added, to fully demonstrate extra ordinary sensitivity of the VTS project. First one is the BlueTooth module. And second is a tablet, running android. Device that I have, doesn’t support USB host mode (OTG), otherwise I may be fine w/o BT, just transfer a data over USB cable, as it was done in two previous demo video clips. Have to say, it was not easy to represent 3D perspective on a flat screen, and picture below shows what I designed to complete a task:
Don’t think it requires a comments, the tricky part was to create an elliptical grid to show a distance. The number of circles is not limited to 2, I’d think about how to film next demo video, that ‘d show a “volume”.
Enjoy the movie:
There are two apples, and arduino measure position in 3D space both of them. X, Y, and Z coordinates plus P – power of reflected ultrasonic wave used to draw circles, with different colors. You can see movement of the red circle on screen when first apples moves.
edited on 21-08-2014
After thinking awhile how to show a “volume” on a flat tablet screen, I decide to remove filtering stage in a software, when a bunch of consecutive “layers” were shown as one single ring (object) on a screen. Now each packet of data received from single “spherical” layer creates a circle. As always packet includes X, Y, Z, and P. To make an image “clear” there are two others filters left over in the processing algorithm. One is rejecting data below ( selectable in a menu ) power threshold, and another rejects anything thats located farther specific (again, selectable) distance. This is why in a video you can see only a ball, but not me – operator making a movie.
Here is how the ball looks like on radar screen:
That;s it for now.