UltraSonic Range Finder, Help

[dr who]

Does any one know how to connect the Parallax UltraSonic Range Finder model#28015 to a ServoPod? all the Newmicros examples indicate a 4 wire setup, Parallax Ultrasonic only has 3 wires.

So please if you have any examples let me know..

Thank you in advance..
The Dr

[RMDumse]

We've never seen one of those Parallax ultrasonic rangers. Do you have one of the rangers you could loan us? or if we write code will you try it and work with us to bring it into operation?

It really doesn't look that complicated. Basically you just combine the two signals used on the Devantech SRF04 together.

You need to make a timer an output with the output low. Then switch it high and low again. Then you need to turn the timer around to do input and measure the pulse width it measures coming back.

Using a capture loop first, just to make it easy for debugging, I'd try this:

: PING TA0 OFF TA0 ON TA0 OFF TA0 SET-PWM-IN BEGIN CHK-PWM-IN ?DUP UNTIL . ;

That will give you some raw number, which 127 / . ." in." would probably give you scaled to inches (based on the conversion I found in the SRF04 appnote).

Want to give that a try and let us know? or send one out for us to test?

[dr who]

Yes, yes

The programme works, thanks, excellent.

Thank you, i can now work out a working programme.


Cheers Marcel..
"What's in your Droid"