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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