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operate relay by phone...

A

Andy C

Jan 1, 1970
0
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help
many thanks !
andy
 
A

Anthony Fremont

Jan 1, 1970
0
Andy said:
hi there - does anyone know of any device or can think of any simple
way to momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset
remotely if there are any problems (e.g. the software crashes)- the
relay would just 'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow
operates the relay if it rings... but this has the problem that it
might ring when it's not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device
already on the market? there is a second pc on site if that is any

You might want to look for "watchdog" cards for the PC. They will detect a
hung machine and perform a reboot automatically. There are also variations
that have a dial-in ability. If you have full-time internet, then that
would provide a path in as well. For example:
http://www.bomara.com/cps/reboot-remote-control.htm
 
R

Rich Webb

Jan 1, 1970
0
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help
many thanks !

Do a 'net search for "DTMF kit" or "DTMF remote" or similar. There are
scores of kits (and full-up modules) that use the "bleepty-bleep" DTMF
tones to remotely control relays.

One example of a kit
<http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=DCI1C>
and a commercial unit <http://www.conex-electro.com/DT40/DT40.html>

There are also plans/prints/sourcecode if you're into roll-yer-own.
 
J

John Fields

Jan 1, 1970
0
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help
many thanks !
andy

---
Do a ring detect to take the phone line off-hook and connect it to a
DTMF decoder, then when you press the desired digit (or series of
digits) on the remote keypad, decode the output of the DTMF decoder
and use that to start a one-shot which operates the relay and then
puts the line back on-hook when it times out.
 
B

Bob Masta

Jan 1, 1970
0
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help
many thanks !
andy

Hmm, phone answering machines often have a
provision for you to retreive your messages from
another phone. Typically you wait for the machine to
pick up, then enter a 2-digit code. I wonder if there is
some way to hot-wire one of these to be the "front end"
that drives your relay?

Just a thought...


Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!
 
S

Si Ballenger

Jan 1, 1970
0
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help
many thanks !
andy

The below x10 telephone gizmo has been used by sys admins for
many years to reboot remote servers that have hung. Just put the
control module on the power supply to the computer to toggle the
power and cause a cold reboot. Looks like they are now being
phased out.

http://www.x10.com/products/x10_tr16a.htm
 
M

Michael A. Terrell

Jan 1, 1970
0
Andy said:
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help
many thanks !
andy


Here is a commercial product used in CATV and remote video switching
by TV stations.

http://www.monroe-electronics.com/CATV_PAGES/remote_control.htm


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
J

jasen

Jan 1, 1970
0
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?

I think there's an X10 module for that.
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)

many phones can be programmed to ignore calls from unknown numbers.

another option would be to make a silent ringtone for calls from most
numbers and a noisy one for your designated numbers
 
C

Clint Sharp

Jan 1, 1970
0
Andy C said:
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
Lots of decent DVR cards have a built in watchdog circuit that will
reset the PC if it crashes.
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help
Sure, send it an SMS, buy the latest PDF issue of EPE Mag from
http://www.epemag.wimborne.co.uk/

It's got a project that uses an old Nokia mobile phone to control remote
appliances via SMS messages, you send the 'phone the correct message, it
resets your PC.
 
R

Rich Grise

Jan 1, 1970
0
hi there - does anyone know of any device or can think of any simple way to
momentarily operative a relay remotely by phone ?
our cctv cameras run on a PC which we need to be able to reset remotely if
there are any problems (e.g. the software crashes)- the relay would just
'press' the reset button on the pc
all i can think of is to buy a cheap mobile phone which somehow operates the
relay if it rings... but this has the problem that it might ring when it's
not wanted (wrong number etc.)
anyone got any good ideas? maybe there is some suitable device already on
the market? there is a second pc on site if that is any help

Get an ordinary answering machine, tap into the speaker, and use a 2-tone
(DTMF) decoder on the audio output to give you one or a sequence of
keypresses, that will then trigger your relay. You'd need either a micro
of some kind or a handful of ordinary logic.

Call the remote number, when the machine picks up, punch in your code
and hang up. The code is important so that if somebody mistakenly dials
your remote, it won't automatically reset your system.

Good Luck!
Rich
 
A

Andy C

Jan 1, 1970
0
Lots of decent DVR cards have a built in watchdog circuit that will
reset the PC if it crashes.

the card actually does have this feature - i didn't realise what it was
though !
i'll try it :)
Sure, send it an SMS, buy the latest PDF issue of EPE Mag from
http://www.epemag.wimborne.co.uk/

It's got a project that uses an old Nokia mobile phone to control remote
appliances via SMS messages, you send the 'phone the correct message, it
resets your PC.

lots of really good ideas - thanks everyone ! that nokia project looks like
it would be absolutely perfect !
anyone (in the UK) fancy building one for me for a fee ? !!
email if interested [email protected] remove the word 'bogus'
from the email address
this is another similar project i found...
http://www.elektor-electronics.co.uk/Default.aspx?tabid=28&year=2005&month=11&art=52926
thanks again,
andy
 
Q

quietguy

Jan 1, 1970
0
You can buy units that will operate a relay etc upon receiving an SMS call - a
cheap and easy way that should do the trick

David
 
Q

quietguy

Jan 1, 1970
0
Whoops, forgot to add that Jaycar sells those SMS controllers - have a look at
their online catalog

David
 
A

Andy C

Jan 1, 1970
0
Whoops, forgot to add that Jaycar sells those SMS controllers - have a look at
their online catalog

perfect! i ordered it !
many thanks :)
 
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