Hum, Iv NOT done this, but am working towards a similar goal.
Could you elaborate on what is meant by "the detection of echoes beyond the
I read this to mean detecting and objects relative location as it changes
Detecting and object that is "beyond" the first echo return. i.e. two
objects, one behind the other, relative to the sonar unit of course. Can
this even be done?
Here is my plan, perhaps it will help you.
I intend to create a 8 X 8 occupancy grid representing the 180 degs. of
space in front of my sonar unit.
For each of the 8 sonar pulse along my 180 deg. Sweep:
Find the distance of the echo return (x)
Evaluate x and place in 1 of 8 appropriate ranges
Read my sweep location (y)
Mark x, y grid location as "occupied"
Backfill all grids BEYOND x (in y column) as "occupied"
Move to next sweep position
Sounds easy enough (lol.. implementing this will keep me up late for a few
8x8 might seem a bit "course" but should be good enough for my obstacle
I had originally planned on running a flooding algorithm to determine my
route, but I realized I simply need to choose the y column that has the
furthest away unoccupied grid x location... Hey wait a second! Now that I
have written it out, I realize I don't even need a grid. An array of 8
bytes corresponding to the 8 sonar pulse location on my 180 deg. sweep, with
the values of each element being the distance to the echo return would
achieve exactly the same thing. Ok, guess Im not ready for this.. lol
Hope my ramblings provides some help to some one.. oh well, it was good for
yeah. the sonar unit (srf08) will detect 16 echoes. So, the farther
away the object is that the sonar bounced off, the farther out the
echo. Problem is that the echos can come from a wide area in the
direction the sonar is facing in. It seems you could make a program
to take all 16 echos from a 180 degree scan....say take a sonar
reading every 5 degrees. I guess I just need to do it and see how it
looks on a graph.
yes, read above. You can detect echo's after the first with most
sonar units, I think. You can do so with hacks out of polaroid
interesting stuff. I'll read it more closely later.
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