Please let me know if your design works? I am interesting in this
application for my DSL at home also. Thanks.

----- Original Message -----
From: "Barry Michels" <bmichels@EPIX.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, February 22, 2002 11:52 PM
Subject: Re: [PIC]: Serial Port Powered WDT


> Well, it took 4 hours, one 555, 3 resistors, 2 diodes, 1 cap, a piece of
> perf board and several inches of solder.  It's alive!  When there's no
data
> flowing on the serial port, the relay stays energized (I'm using a small,
> low current reed relay).  All it takes is 1 or 2 characters to de-energize
> the relay for a few seconds.  I'm going to try it out at the office next
> week.  I just hope it doesn't burn out the serial port...
>
> Thanks for the help
>
> Barry
>
> ----- Original Message -----
> From: "Aaron K" <aaron@LUMINUS.CX>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Friday, February 22, 2002 6:47 PM
> Subject: Re: [PIC]: Serial Port Powered WDT
>
>
> > Something that I think would work well and be very low power (and
simple)
> > would be to make a small one shot timer out of a 555 (the monostable
> setup)
> > thas is triggered by the first RS232 '0' bit in the byte (which would be
a
> > +5 to +17 or so DC). So you could set up the timing so once this '0' bit
> is
> > recieved, it would start the 555 timer triggering the relay. Then, when
> ever
> > you wanted to turn on the relay, you'd just send any byte out (as long
as
> it
> > has a '0' bit in it) on the serial port. You wouldn't need a RS232
> converter
> > either, just hook up the RX pin directly to the 555 with a resistor and
> > (probably) some protection diodes, similar to the way the PICs do it on
> > their pins.
> >
> > Aaron
> >
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>

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