Path: utzoo!attcan!uunet!husc6!uwvax!rutgers!apple!lemke
From: lemke@Apple.COM (Steve Lemke)
Newsgroups: sci.electronics
Subject: Re: Build a "simple" timing device.
Message-ID: <16629@apple.Apple.COM>
Date: 5 Sep 88 18:19:54 GMT
References: <2283@m2-net.UUCP>
Reply-To: lemke@apple.com.UUCP (Steve Lemke)
Organization: Apple Computer Inc, Cupertino, CA
Lines: 40

In article <2283@m2-net.UUCP> ba@m-net.UUCP (Bill Allen) writes:
>I need to build the follow device:
>You hit a button on a very small box.  25 seconds later a
>gentle beep is heard.  A second beep 3 seconds later.  A
>third and final beep after an additional 2 seconds.  (That's
>25-28-30 secs).   The unit then resets itself awaiting another
>button press.
>
>Accuracy need only be +/-0.25 second.
>
>Sounds simple?
yes, as a matter of fact...
>---------------------------------------------------------
>Reply-To: ba@m-net.UUCP (Bill Allen Beogelein)
>Organization: M-NET, Ann Arbor, MI
>---------------------------------------------------------

Go to Radio Shack and get a 558 quad timer chip.  If they don't have one, get
two 556 dual timer chips, and if you're at strike two, get three 555 timers.
The package may or may not have enough details on the back (probably not), so
you might find a book on using the 555 series (they all work the same).  You
want to set up the first on with the resistors and caps set to trigger at 25
seconds, which sounds your alarm and starts the second timer which triggers
at 2 seconds, sounds another alarm, and starts the third timer which triggers
at 3 seconds and sounds the final alarm.  If you want to use the same alarm,
you might use a three-input or gate tied to the three outputs.  Also, depending
on the alarm, you might want to use a fourth timer as a "one-shot" to only
sound the alarm for as long as you want it to be on.

Unfortunately, I don't have any of my data books nearby, so I can't give you
an exact schematic (and some things are still left unspecified, such as the
alarm you want to use and if you want to use three different ones or the same
one).  Perhaps you can answer these additional questions and someone can pro-
vide a schematic for you if you can't find something helpful in a book at RS.

			===== Steve Lemke =====
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All opinions are, of course, mine, and could never belong to anyone else!