push button control of RS232 cctv controller

C

Chris

Guest
I have a CCTV controller (quad switcher) that has an RS232 interface.
The output of the switcher can be controlled by simple ASCII commands.
e.g. /01 to switch to full screen display of input 1.

I want to allow a remote site to be able to switch the controller, by
pushing a button corresponding to the display that they want to see.

The remote site is about 300 metres away.

I have plenty of standard telephone cable pairs available.

To save me reinventing the wheel. Has anybody got a circuit for an
encoder that will take what will effectively be a set of five dry
contact inputs (quad display plus cameras 1 to 4) and produce a
suitably formatted ASCII output that can drive an RS232 interface, or
something that will drive an RS232 driver such as the MAX232?

A few years ago it was possible to buy controllers that had a simple
set of dry contacts on the back, but the one I had got zapped by
lightning, and they don't seem to available anymore; at least not from
my supplier.

Cheers
Chris
 
In article <d0ba99f6.0403160616.152b803@posting.google.com>, Chris
<chris.harris@cwfi.co.fk> writes
I have a CCTV controller (quad switcher) that has an RS232 interface.
The output of the switcher can be controlled by simple ASCII commands.
e.g. /01 to switch to full screen display of input 1.

I want to allow a remote site to be able to switch the controller, by
pushing a button corresponding to the display that they want to see.

The remote site is about 300 metres away.

I have plenty of standard telephone cable pairs available.

To save me reinventing the wheel. Has anybody got a circuit for an
encoder that will take what will effectively be a set of five dry
contact inputs (quad display plus cameras 1 to 4) and produce a
suitably formatted ASCII output that can drive an RS232 interface, or
something that will drive an RS232 driver such as the MAX232?

A few years ago it was possible to buy controllers that had a simple
set of dry contacts on the back, but the one I had got zapped by
lightning, and they don't seem to available anymore; at least not from
my supplier.

Don't know where you are in the world; Milford Instruments in the UK
Click to expand...
(www.milinst.com) do a "Basic Stamp" kit which could be programmed to do
this very quickly.
--
Tim Mitchell
 
On 16 Mar 2004 06:16:59 -0800, chris.harris@cwfi.co.fk (Chris) wrote:

To save me reinventing the wheel. Has anybody got a circuit for an
encoder that will take what will effectively be a set of five dry
contact inputs (quad display plus cameras 1 to 4) and produce a
suitably formatted ASCII output that can drive an RS232 interface, or
something that will drive an RS232 driver such as the MAX232?
Click to expand...
I don't think it's a circuit you need - any (sensible) microprocessor (e.g Atmel
AVR AT90s2313) will do the job. You just have to define what ASCII strings you
need for each button and write/commission the firmware.
Although if you are controlling the device locally by RS232 /as well/ then you
will have a problem of combining two RS232 transmitters.

Geo
 
I have a CCTV controller (quad switcher) that has an RS232 interface.
The output of the switcher can be controlled by simple ASCII commands.
e.g. /01 to switch to full screen display of input 1.

I want to allow a remote site to be able to switch the controller, by
pushing a button corresponding to the display that they want to see.

The remote site is about 300 metres away.

I have plenty of standard telephone cable pairs available.

To save me reinventing the wheel. Has anybody got a circuit for an
encoder that will take what will effectively be a set of five dry
contact inputs (quad display plus cameras 1 to 4) and produce a
suitably formatted ASCII output that can drive an RS232 interface, or
something that will drive an RS232 driver such as the MAX232?

A few years ago it was possible to buy controllers that had a simple
set of dry contacts on the back, but the one I had got zapped by
lightning, and they don't seem to available anymore; at least not from
my supplier.

Don't know where you are in the world; Milford Instruments in the UK
(www.milinst.com) do a "Basic Stamp" kit which could be programmed to do
this very quickly.
Click to expand...
I was thinking of using a Stamp, but most of my electronics
training/experience is pre stamp ;-) But maybe this is the excuse I have
been looking for to go down that route and have a play.

Was thinking that maybe somebody had designed/produced an IC to do it.

I'm in the Falkland Island by the way. I can get things from the UK fairly
easy.

Thanks
Chris
 
I read in sci.electronics.design that Chris Harris
<chris.harris@cwfi.co.fk> wrote (in <c379h3$2524cp$1@ID-134007.news.uni-
berlin.de>) about 'push button control of RS232 cctv controller', on
Tue, 16 Mar 2004:
I was thinking of using a Stamp, but most of my electronics
training/experience is pre stamp ;-) But maybe this is the excuse I have
been looking for to go down that route and have a play.
Click to expand...
I managed to learn some BASIC, first on an Apple ][ and then on BBC
Micros. But I've never manage to get into any other programing language.
You can write BBC BASIC, with very few comments, that humans can read
and understand, which is sometimes useful. (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
On a sunny day (16 Mar 2004 06:16:59 -0800) it happened
chris.harris@cwfi.co.fk (Chris) wrote in
<d0ba99f6.0403160616.152b803@posting.google.com>:

I have a CCTV controller (quad switcher) that has an RS232 interface.
The output of the switcher can be controlled by simple ASCII commands.
e.g. /01 to switch to full screen display of input 1.

I want to allow a remote site to be able to switch the controller, by
pushing a button corresponding to the display that they want to see.

The remote site is about 300 metres away.

I have plenty of standard telephone cable pairs available.

To save me reinventing the wheel. Has anybody got a circuit for an
encoder that will take what will effectively be a set of five dry
contact inputs (quad display plus cameras 1 to 4) and produce a
suitably formatted ASCII output that can drive an RS232 interface, or
something that will drive an RS232 driver such as the MAX232?

A few years ago it was possible to buy controllers that had a simple
set of dry contacts on the back, but the one I had got zapped by
lightning, and they don't seem to available anymore; at least not from
my supplier.

Cheers
Chris
You could program a PIC microcontroller, add a RS232 interface chip
Click to expand...
and use some optocouplers in the logic inputs.
Learning to program one could make other projects possible for you
later on.
JP
 
To save me reinventing the wheel. Has anybody got a circuit for an
encoder that will take what will effectively be a set of five dry
contact inputs (quad display plus cameras 1 to 4) and produce a
suitably formatted ASCII output that can drive an RS232 interface, or
something that will drive an RS232 driver such as the MAX232?

I don't think it's a circuit you need - any (sensible) microprocessor (e.g
Atmel
AVR AT90s2313) will do the job. You just have to define what ASCII strings
you
need for each button and write/commission the firmware.
Although if you are controlling the device locally by RS232 /as well/ then
you
will have a problem of combining two RS232 transmitters.
Click to expand...
Local control is by front panel push button, but is never used anyway. If
there is anybody at the location they can look out the windows ;-)

What do you see as the advantages of developing a microcontroller circuit
over using a STAMP?

Chris
 
I was thinking of using a Stamp, but most of my electronics
training/experience is pre stamp ;-) But maybe this is the excuse I have
been looking for to go down that route and have a play.

I managed to learn some BASIC, first on an Apple ][ and then on BBC
Micros. But I've never manage to get into any other programing language.
You can write BBC BASIC, with very few comments, that humans can read
and understand, which is sometimes useful. (;-)
Click to expand...
I did a bit of programming in BBC BASIC, satellite tracking, and weather
satellite reception mainly. I was also competent at using C but haven't done
any programming for at least 10 years.

I guess it will come back soon enough, if they grey cells aren't gone
forever!

Chris
 
Chris Harris wrote:

I did a bit of programming in BBC BASIC, satellite tracking, and weather
satellite reception mainly. I was also competent at using C but haven't done
any programming for at least 10 years.

I guess it will come back soon enough, if they grey cells aren't gone
forever!

Chris
Click to expand...
What you don't use you lose.
 
Take a look at www.av-commander.com

The Commander generates RS232 signals from up to 8 pushbuttons and can be
programmed to send any data string from any button at any standard baud
rate. Panels can be supplied blank or printed.

Hope this might help with a quick solution

Peter
"Chris" <chris.harris@cwfi.co.fk> wrote in message
news:d0ba99f6.0403160616.152b803@posting.google.com...
I have a CCTV controller (quad switcher) that has an RS232 interface.
The output of the switcher can be controlled by simple ASCII commands.
e.g. /01 to switch to full screen display of input 1.

I want to allow a remote site to be able to switch the controller, by
pushing a button corresponding to the display that they want to see.

The remote site is about 300 metres away.

I have plenty of standard telephone cable pairs available.

To save me reinventing the wheel. Has anybody got a circuit for an
encoder that will take what will effectively be a set of five dry
contact inputs (quad display plus cameras 1 to 4) and produce a
suitably formatted ASCII output that can drive an RS232 interface, or
something that will drive an RS232 driver such as the MAX232?

A few years ago it was possible to buy controllers that had a simple
set of dry contacts on the back, but the one I had got zapped by
lightning, and they don't seem to available anymore; at least not from
my supplier.

Cheers
Chris
Click to expand...
 
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