On Sun, 17 Mar 2002, Duane B wrote:

> Would it be possible to get a snippet of the code to see how to set this all
> up.   This whole PIC, C code, robotic thing is very new to me.  Now I don't
> want to cheat you out of anything because I know you have put a lot of time
> into the code you wrote.  But, enough to get me going would be appreciated.
> The one camera board, how did you connect it to the PIC, and which PIC did
> you use?

I used a 16F84, but pretty much any PIC will do.  Interface to the sonar
unit I have (Polaroid, but not from a camera) consists of INIT and ECHO...
raising INIT fires the sonar, ECHO is raised by the sonar unit when an
echo is detected.  I believe there are pull-up resistors required on both
lines, not sure right at the moment.  Like I said, I set up a TIMER0
interrupt for 900uS, and during that interrupt service routine increment
the variable sonar_range.  That way all you have to do to get a range
reading is something like this:

    sonar_range = 0;                 // Clear range value for this ping
    output_high(sonar_init);         // Send a ping
    while((sonar_range < 80) &&      // Wait for either timeout
      !input(sonar_echo));           // OR an echo return...
    if(!input(sonar_echo)) {         // If it's a timeout, return max range
       range = max_range;
    } else {
       range = sonar_range / 2;      // Otherwise return the measured range
    }
    output_low(sonar_init);          // Turn off INIT to sonar module

I also use PCW.  Hope this helps out some.

Dale

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