Cheap or free auto-shutdown setup

Bernd Felsche bernie at DIALix.oz.au
Wed Oct 3 15:03:58 AEST 1990


In article <257 at bongo.UUCP> julian at bongo.UUCP (Julian Macassey) writes:
[previous qoute deleted]
>	So to summarise, here is what needs to be done:
>
>1.	Identify a power outage
>
Easy via an RS-232 line monitor, of any religion you like.

>2.	Start shutdown
>
Shell script.
>3.	Abort shutdown, or reboot if power returns within a specified 
>period.
>
Shell script.
>4.	Switch off machine after shutdown is successful
>
RS-232 DTR line can be dropped, allowing a relay to drop out after a
nominal interval... no more power.

>5.	Switch machine back on after power has been restored for a certain 
>length of time.

Monitor power presence and after a safe delay (for the UPS to come
to a usable charge state), enable the computer's power relay.

All the above hardware can be put together with a few CMOS logic chips,
timers and passive components... oh and one or two relays.  Hardware
cost is about $30, maybe less.  Design time about 1 day.
Construction, depends.

If you prefer, send me US$3000 and I'll make one for you :-)

bernie



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