Multiple PING)) Code Logic Suggestions

Bill Chennault · 2010-02-05 19:50

All--

I would like to upgrade my robot with multiple pings. It is my thought that if I had 8 PING)) units, I could easily cover the machine's entire "sight distance" out as far as necessary (36" is fine.) However, I can't get a handle on the logic to implement the code which will let me determine the sensor reporting the most distance ("most distance"·would be·a clear path: there are combinations of clear paths, ie; left-front, right-front, etc., but that makes it worse).

Other than a bunch of IF/THEN statements, how would you do it? Maybe it is simple and I am not seeing the forest through the trees.

Thanks!

--Bill

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Mike Green · 2010-02-05 20:12

If you use sequential I/O pins for the PING)))s, you could set up a simple loop to fill an array with the values from each of the PING)))s. You'd then have another loop that would look for the highest value (and its index). That would represent the clear path. You could construct your loop to either save the first "highest" value seen or the last "highest" value seen, whichever behavior you want.

If you want to change the search order, you could just rearrange the PING))) connections so they're scanned in the order you want.

If you have 8 PING)))s, that would take about 160ms to make a pass through all of them.

Zoot · 2010-02-05 20:27

e.g.


PingsPins PIN 0 ' as an implied array, using pins 0-7
maxDist VAR Word
minDist VAR Word
pingDist VAR Word(8)
maxPing VAR Nib ' saved idx of ping
minPing VAR Nib
i VAR Nib


LoopMe:
maxDist = $0000
minDist = $FFFF
FOR i = 0 TO 7
   PULSOUT PingsPins(i), 2
   PULSIN PingsPins(i), pingDist(i)
   IF pingDist(i) < minDist THEN
      minDist = pingDist(i)
      minPing = i
   ENDIF
   IF pingDist(i) > maxDist THEN
      maxDist = pingDist(i)
      maxPing = i
   ENDIF
NEXT

DEBUG "max dist is Ping #", DEC1 maxPing,": ", DEC5 maxPing, CR,
DEBUG "min dist is Ping #", DEC1 minPing,": ", DEC5 minPing, CR
PAUSE 2000
GOTO LoopMe

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Bill Chennault · 2010-02-05 20:42

Mike and Zoot--

Mike, thanks for the logic. I am glad I quit thinking about it. I am going to attempt to poll the PING))s in a timed interrupt (SX/B) and return their distances to the main routine.

Zoot! Ha! Thanks for the code!

--Bill

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
You are what you write.

Post Edited (Bill Chennault) : 2/5/2010 8:48:04 PM GMT

Multiple PING)) Code Logic Suggestions

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