Re: Controlling a relay via cellular phone.....
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Posted by Jamie on July 17, 2006, 8:36 am
Please log in for more thread options I got in late on this thread. Basically, it'd be pretty easy to rig a relay device to the reset pin from the phone ringer. But.. you'll need a dedicated phone for that. (As I understand it, this is basically how the terrorists do their business, 'cept it's a bomb instead of a bombed computer..) Not really advisable though, unless you want any phone call to reboot the computer. A watchdog timer is the best approach, the idea is to wire it like a dead man switch, (gee, morbid today) so that failing to send it a signal will cause a reboot. If it's a specific piece of network software being monitored, a software solution would be far easier, the "watchdog" could do double duty, for example, attempting to load a page from a web server, if it fails, reboot the web server and set a flag so the next iteration checks to see it restarted proper if THAT fails, then stop sending signals to the watchdog timer and await a reboot. That way, you won't need to reboot the comptuter when a specific application dies and if you (the watchdog process) fail to send a signal to the watchdog timer, it still does a reboot. UNIX'ish operating systems, this would be easy to do. Not sure about windows. If you insist on going the phone route, I'd probably look for an old answering machine, the kind with a tape that allow you to fetch your messages via remote via a code. Then, rig into THAT machine (playback motor or something, look for a led or other signal that is only active when fetching messages) At least you'd have a minimal password protection scheme. Jamie -- http://www.geniegate.com Custom web programming guhzo_42@lnubb.pbz (rot13) User Management Solutions | |||||||||||||
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Posted by jasen on July 18, 2006, 2:33 am
Please log in for more thread options >>the calls to the watchdog resetting routine need to come from the software
>>that's being monitored, if it's not done this way and the payload software >>crashes ties the network in a knot but the watchdog pinger keeps pinging >>you're no better off. >
it,
> I got in late on this thread. > > Basically, it'd be pretty easy to rig a relay device to the reset pin from the > phone ringer. But.. you'll need a dedicated phone for that. (As I understand > this is basically how the terrorists do their business, 'cept it's a bomb
instead
> of a bombed computer..)
computer.
> > Not really advisable though, unless you want any phone call to reboot the if you've got free caller-id (it';s free on mobiles here) you can easily set it so that only calls from trusted parties reboot it. > A watchdog timer is the best approach, the idea is to wire it like a dead man
switch,
> (gee, morbid today) so that failing to send it a signal will cause a reboot.
solution
> > If it's a specific piece of network software being monitored, a software > would be far easier, the "watchdog" could do double duty, for example,
attempting
> to load a page from a web server, if it fails, reboot the web server and set a
flag
> so the next iteration checks to see it restarted proper if THAT fails, then
stop sending
> signals to the watchdog timer and await a reboot.
dies and
> > That way, you won't need to reboot the comptuter when a specific application > if you (the watchdog process) fail to send a signal to the watchdog timer, it
still does
> a reboot.
> UNIX'ish operating systems, this would be easy to do. Not sure about windows.
should be do-able on windows. > If you insist on going the phone route, I'd probably look for an old
>answering machine, yeah, that'd work well on a fixed line. > Jamie
-- Bye. Jasen | |||||||||||||
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Posted by EsDee on July 21, 2006, 1:33 pm
Please log in for more thread options I got the Velleman kit MK160.
It's in a plastic box together with an old mobile phone. When the phone's display lits up, it triggers the MK160. On this device I can select the switching time from 0.5 seconds to 1 hour. I set it to 2 seconds, connected it to the reset button, and configured the phone to only accept my number as allowed caller. All other numbers are blocked. Works great! Thanks for the input. Marcel >>>the calls to the watchdog resetting routine need to come from the
>>>software >>>that's being monitored, if it's not done this way and the payload >>>software >>>crashes ties the network in a knot but the watchdog pinger keeps pinging >>>you're no better off. >>
>> I got in late on this thread. >> >> Basically, it'd be pretty easy to rig a relay device to the reset pin >> from the >> phone ringer. But.. you'll need a dedicated phone for that. (As I >> understand it, >> this is basically how the terrorists do their business, 'cept it's a bomb >> instead >> of a bombed computer..) >> >> Not really advisable though, unless you want any phone call to reboot the >> computer. >
> if you've got free caller-id (it';s free on mobiles here) you can easily > set > it so that only calls from trusted parties reboot it. > >> A watchdog timer is the best approach, the idea is to wire it like a dead
>> man switch, >> (gee, morbid today) so that failing to send it a signal will cause a >> reboot. >> >> If it's a specific piece of network software being monitored, a software >> solution >> would be far easier, the "watchdog" could do double duty, for example, >> attempting >> to load a page from a web server, if it fails, reboot the web server and >> set a flag >> so the next iteration checks to see it restarted proper if THAT fails, >> then stop sending >> signals to the watchdog timer and await a reboot. >> >> That way, you won't need to reboot the comptuter when a specific >> application dies and >> if you (the watchdog process) fail to send a signal to the watchdog >> timer, it still does >> a reboot. >
>> UNIX'ish operating systems, this would be easy to do. Not sure about
>> windows. >
> should be do-able on windows. > >> If you insist on going the phone route, I'd probably look for an old
>>answering machine, >
> yeah, that'd work well on a fixed line. > >> Jamie
>
> > -- > > Bye. > Jasen | |||||||||||||
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Posted by martin griffith on July 21, 2006, 2:18 pm
Please log in for more thread options On Fri, 21 Jul 2006 19:33:52 +0200, in sci.electronics.design "EsDee"
>I got the Velleman kit MK160.
Like this?
>It's in a plastic box together with an old mobile phone. > >When the phone's display lits up, it triggers the MK160. >On this device I can select the switching time from 0.5 seconds to 1 hour. >I set it to 2 seconds, connected it to the reset button, and configured the >phone to only accept my number as allowed caller. All other numbers are >blocked. > >Works great! > >Thanks for the input. >Marcel > > http://tinyurl.com/zl5tc martin | |||||||||||||
>that's being monitored, if it's not done this way and the payload software
>crashes ties the network in a knot but the watchdog pinger keeps pinging
>you're no better off.