Well, if you *really* want old school, how about an Amperite time delay tube??

If it was good enough for Collins and the like, it should be good enough for ham radio :-).

JIM WB6NIL

> Date: Fri, 27 Jan 2012 15:41:32 +0900
> From: a.errington@lancaster.ac.uk
> To: yokshs@gmail.com
> CC: app_rpt-users@ohnosec.org
> Subject: Re: [App_rpt-users] GPIO fan control
>
> On Fri, January 27, 2012 12:43, K&R Yoksh wrote:
> > I forgot to mention that I've also had good luck assigning multiple
> > Parallel
> > port pins to PTT in usbradio.conf or simpleusb.conf, such as:
> >
> > pp3 = ptt pp4 = ptt
> >
> > Again, I'd rather not cycle a relay with every PTT. I'd much prefer the
> > fan run for 2 minutes or so after the last PTT, then shut off. That would
> > save a lot of wear and tear on the fan and relay.
>
> How about a 555 timer IC hooked up to PTT in one-shot mode with a 2 minute
> timer?
>
> Very old skool, but might do the job.
>
> 73,
>
> Andrew
> ZL3AME
>
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