Re: TI-H: Scanning Sonar

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: Scanning Sonar
From: Michael McCann <mccann@telalink.net>
Date: Mon, 24 Nov 1997 15:28:56 -0600
References: <19971124100633.28576.qmail@hotmail.com>
Reply-To: ti-hardware@lists.ticalc.org



Muhammed Galadima wrote:

> 1. calibrate period (especially necessary with TI's) by putting an
> object in front of the sonar and allowing it to turn, detecting the
> object twice and timing that.

Never thought about automated calabration before but it would be very easy
to add tothe software.

> 2. calibrate speed of sound (changes w/temp)
>

I probably wouldn't add this, I mean this sonar is just for fun right :)


>3. Now on the calcs' screen, there is a rotating arm. From step 1, its'

> position is set to always match that of the sonar. The sonar normally
> will get no response until there is something in the way (and in range).
> It will send a signal to the calc whenever it sends a pulse, resetting
> the calcs' timer each time. If it receives an echo pulse it will send a
> different signal to the calc. The calc will, at the current location of
> the rotating arm on the screen, place a dot in correspondence with the
> time elapsed between sending the pulsse and receiving an echo.
>

Since TI85s don't have built in timers, I'd suggest an external 555 IC but
you've gotthe basic idea.  In the program I would most definantly include
more than on graphical interface.  Probably 1) Old-style radar like the one
you described and 2) a Terrain Style
like the one I diagramed earlier.

> Maybe something like a PIC will be needed to to the timings?

I'm still realtivly new to electronics but seems like a pic might be
over-kill for a simplesend-time-stop-reset circut.  If anybody could
hardwire one of these things I'd probably pay.

Michael,
mccann@telalink.net

P.s.  Scanning sonar is the kind that turns

>

> >
> >> if youre interested, my friend and i designed an eight bit parrallel
> i/o
> >> system a while ago.  we never actually drew up the schem, but we got
> all
> >> the design in our heads (chips numbers included).
> >>
> >> we never built one because we don't have a use for it yet.  the
> initial
> >> idea was for motion control but other things have taken up time
> since.
> >> also, we knew how the algorithms would work but never commited them
> to
> >> asm.  those are still in suedo-code waiting to be written into a
> driver.
> >>
> >> where does the data end up when the sonar is done with it?
> >>
> >> a sonar sounds like an awsome idea; how is it done?
> >>
> >> Matthew
> >
> >I'm interested if you could put it down.  The program would just
> translate
> >the time it tookfor the sound to bounce back and map it on the calc.
> >Depending on the speed and distance before the sound won't return. I'd
> do
> >something like 1 pixel = 2 meters or so.
> >IF you wanted it to scan (Turn) the RPM of the actual motor comes into
> the
> >program.
> >
> >Here's what I think the output might look like.
> >
> >
> >
> >
> >--XXXXXXXXXXXXXXXXX
> >----XXXXXXXXXXXXXXXX
> >---------------XXXXXXXXXX
> >------------------------XXX----
> >---------------------------------
> >---------------------------------
> >---------------------------------
> >
> >
>
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References:

Re: TI-H: Scanning Sonar

From: "Muhammed Galadima" <mj_galadima@hotmail.com>