Post by thread:[PIC]: Need some help with a PIC monotoring system

Hi everyone. I need to build a system for me to monitor my guards. What I need this system to do is: ~ every hour (or 1/2 hr) notify the guard that he has to patrol ~ the guard has to 'check-in' at various check points (there are four of them, I was thinking about using long range remotes with a receiver in the guard room. The guard has to check-in, in a sequence, so that he cannot stand in one place and 'press the button' four times.) ~ Once the guard has completed his patrol, he has to 'reset' the system by pressing a button inside the guard room. ~ If the patrol was a success (there where no problems and the guard checked-in in the specified time limit) then the system must notify the control room which is located at different premises, either by radio via a repeater or through telephone lines using a tele-dialler, that the patrol was successful and that all is ok. ~ If something happened on the patrol (if the time limit expired or the guard pressed his panic remote) then the system must notify the control room that there is a problem and that someone must be sent out to the site. Firstly, what is the best way to get the signal to the control room. If the system sends and audio signal (through the use of a voice chip) with a pre-recorded message or some form of data. If it is data, then something must be at the receiving end to decode it, maybe a PC running a program which answers a modem upon detection of a ring and then decodes the data, this will require some programming skills which I mostly lack. But can it be done? Also what PIC would be most suited to this? Could it be possible to use a 16f84? I would appreciate any help that you guys can give. Thanks, Richard -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Wow!!! You have the money to pay the guards?! I don't think you have any problem paying someone to build the system for you! Thomas {Quote hidden}>From: Richard <spam_OUTrichardTakeThisOuTCCTGLOBAL.VIRTUALAVE.NET> >Reply-To: pic microcontroller discussion list <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> >To: PICLISTKILLspamMITVMA.MIT.EDU >Subject: [PIC]: Need some help with a PIC monotoring system >Date: Tue, 17 Apr 2001 21:21:47 +0200 > >Hi everyone. > >I need to build a system for me to monitor my guards. What I need this >system to do is: > ~ every hour (or 1/2 hr) notify the guard that he has to patrol > ~ the guard has to 'check-in' at various check points (there are four >of >them, I was thinking about using long range remotes with a receiver in the >guard room. The guard has to check-in, in a sequence, so that he cannot >stand in one place and 'press the button' four times.) > ~ Once the guard has completed his patrol, he has to 'reset' the >system >by pressing a button inside the guard room. > ~ If the patrol was a success (there where no problems and the guard >checked-in in the specified time limit) then the system must notify the >control room which is located at different premises, either by radio via a >repeater or through telephone lines using a tele-dialler, that the patrol >was successful and that all is ok. > ~ If something happened on the patrol (if the time limit expired or >the >guard pressed his panic remote) then the system must notify the control >room >that there is a problem and that someone must be sent out to the site. > >Firstly, what is the best way to get the signal to the control room. If the >system sends and audio signal (through the use of a voice chip) with a >pre-recorded message or some form of data. If it is data, then something >must be at the receiving end to decode it, maybe a PC running a program >which answers a modem upon detection of a ring and then decodes the data, >this will require some programming skills which I mostly lack. But can it >be >done? > >Also what PIC would be most suited to this? Could it be possible to use a >16f84? > >I would appreciate any help that you guys can give. > >Thanks, >Richard > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

{Quote hidden}>I need to build a system for me to monitor my guards. What I need this >system to do is: > ~ every hour (or 1/2 hr) notify the guard that he has to patrol > ~ the guard has to 'check-in' at various check points (there are four >of >them, I was thinking about using long range remotes with a receiver in the >guard room. The guard has to check-in, in a sequence, so that he cannot >stand in one place and 'press the button' four times.) > ~ Once the guard has completed his patrol, he has to 'reset' the >system >by pressing a button inside the guard room. > ~ If the patrol was a success (there where no problems and the guard >checked-in in the specified time limit) then the system must notify the >control room which is located at different premises, either by radio via a >repeater or through telephone lines using a tele-dialler, that the patrol >was successful and that all is ok. > ~ If something happened on the patrol (if the time limit expired or >the >guard pressed his panic remote) then the system must notify the control >room >that there is a problem and that someone must be sent out to the site. > >Firstly, what is the best way to get the signal to the control room. If the >system sends and audio signal (through the use of a voice chip) with a >pre-recorded message or some form of data. If it is data, then something >must be at the receiving end to decode it, maybe a PC running a program >which answers a modem upon detection of a ring and then decodes the data, >this will require some programming skills which I mostly lack. But can it >be >done? > >Also what PIC would be most suited to this? Could it be possible to use a >16f84? > >I would appreciate any help that you guys can give. > >Thanks, >Richard > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Richard <.....PICLISTKILLspam.....MITVMA.MIT.EDU> wrote: > I need to build a system for me to monitor my guards. Richard: What you've described is a "watchman's clock", various versions of which have been in use for centuries. It'll be much cheaper to buy a system than to build it; if you search the web for "watchman's clock" or "guard tour", I'm certain that you'll find a vendor who has exactly what you need. -Andy === Andrew Warren --- EraseMEaiwspam_OUTTakeThisOuTcypress.com === IPD Systems Engineering, CYSD === Cypress Semiconductor Corporation === === Opinions expressed above do not === necessarily represent those of === Cypress Semiconductor Corporation -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

lol. Actually its a security company. The guards are at one of our clients premises. There is a system available commercially which does something similar to this, but it doesn't offer the sending of the notifications in 'real-time. What it does is logs the time the guards get to the check points, which can be download the next day and printed. But this is not what I want. I need it tell the people in the control the instant there is something wrong(i.e. the guard presses his panic button or something similar). Also, that system has a price tag of over R 6 000.00 (To give you an idea, the average salary of a guard here in South Africa is approx. R 1 500 to R 2 000 a month, so you can see that it is quiet expensive). I would prefer to build one myself at say, tops R 2 500.00 Also over here a PIC16f84 goes for around R 80.00 a piece. That's why I would like to know if that chip will do. Richard. {Original Message removed}

Ok, thanks. I'll do some searching on the net and see what I can get. Richard ----- Original Message ----- From: "Andrew Warren" <aiwspam_OUTCYPRESS.COM> To: <@spam@PICLISTKILLspamMITVMA.MIT.EDU> Sent: Tuesday, April 17, 2001 9:50 PM Subject: Re: [PIC]: Need some help with a PIC monotoring system {Quote hidden}> Richard <KILLspamPICLISTKILLspamMITVMA.MIT.EDU> wrote: > > > I need to build a system for me to monitor my guards. > > Richard: > > What you've described is a "watchman's clock", various versions of > which have been in use for centuries. > > It'll be much cheaper to buy a system than to build it; if you search > the web for "watchman's clock" or "guard tour", I'm certain that > you'll find a vendor who has exactly what you need. > > -Andy > > > === Andrew Warren --- RemoveMEaiwTakeThisOuTcypress.com > === IPD Systems Engineering, CYSD > === Cypress Semiconductor Corporation > === > === Opinions expressed above do not > === necessarily represent those of > === Cypress Semiconductor Corporation > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

I must admit, it sounds like a huge project. But the real trouble is getting the system to communicate with the control room. I built a quick one for the mean time (took almost a day to build and install) it consists of a few timers and four long range remotes and a voice module. The timers are connected to the module and to a relay which PTT's a two-way radio working through a repeater. The thing is that it is a 'community repeater' (from a 2-way radio company) and the audio level is set a bit high so that the repeater rejects sounds (which is normally noise) with levels below the setting. And with the output from the voice module being a bit low it most of the message gets rejected and it comes out sounding like a scratched CD. Now the only way I can think of is to set the levels lower, which would upset the other users on the repeater. If I use the radio on a simplex channel (I.E. not through a repeater), then it works fine, but the distance it has to transmit is to far for simplex. If I can get this communicating thing to work, then I'm sure it becomes a simple task getting the check points and everything to work fine utilising a micro such as a PIC? Richard {Original Message removed}

I've heard of the iButton. Ok I'll look into it. Thanks Douglas, Richard ----- Original Message ----- From: "Douglas Wood" <TakeThisOuTdbwoodEraseMEspam_OUTKC.RR.COM> To: <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> Sent: Tuesday, April 17, 2001 10:57 PM Subject: Re: [PIC]: Need some help with a PIC monotoring system {Quote hidden}> You might try using a Dallas Semi iButton for the ID tag. That should > simplfy the ID part of the project. > > Douglas Wood > Software Engineer > dbwoodEraseME.....kc.rr.com > > Home of the EPICIS Development System for the PIC and SX > http://epicis.piclist.com > > ----- Original Message ----- > From: "Richard" <EraseMErichardCCTGLOBAL.VIRTUALAVE.NET> > To: <RemoveMEPICLISTEraseMEEraseMEMITVMA.MIT.EDU> > Sent: Tuesday, April 17, 2001 3:29 PM > Subject: Re: [PIC]: Need some help with a PIC monotoring system > > > > I must admit, it sounds like a huge project. But the real trouble is > getting > > the system to communicate with the control room. > > > > I built a quick one for the mean time (took almost a day to build and > > install) it consists of a few timers and four long range remotes and a > voice > > module. > > The timers are connected to the module and to a relay which PTT's a > two-way > > radio working through a repeater. The thing is that it is a 'community > > repeater' (from a 2-way radio company) and the audio level is set a bit > high > > so that the repeater rejects sounds (which is normally noise) with levels {Quote hidden}> > below the setting. And with the output from the voice module being a bit > low > > it most of the message gets rejected and it comes out sounding like a > > scratched CD. > > > > Now the only way I can think of is to set the levels lower, which would > > upset the other users on the repeater. > > > > If I use the radio on a simplex channel (I.E. not through a repeater), > then > > it works fine, but the distance it has to transmit is to far for simplex. > > > > If I can get this communicating thing to work, then I'm sure it becomes a > > simple task getting the check points and everything to work fine utilising {Quote hidden}> a > > micro such as a PIC? > > > > Richard > > ----- Original Message ----- > > From: "Drew Vassallo" <RemoveMEsnurplespam_OUTKILLspamHOTMAIL.COM> > > To: <RemoveMEPICLISTTakeThisOuTspamMITVMA.MIT.EDU> > > Sent: Tuesday, April 17, 2001 9:58 PM > > Subject: Re: [PIC]: Need some help with a PIC monotoring system > > > > > > > Sorry for the repost... accidentally hit "send" instead of cancel. > > > > > > >I need to build a system for me to monitor my guards. What I need this > > > >system to do is: > > > > > > This sounds like a major undertaking. EE's would spend months (if not > > more) > > > developing something like this. Why not just see what's available on > the > > > market for timecard-style monitoring? > > > > > > There are a number of access-control manufacturers who may have similar {Quote hidden}> > > products that may suit your needs. > > > > > > --Andrew > > > _________________________________________________________________ > > > Get your FREE download of MSN Explorer at http://explorer.msn.com > > > > > > -- > > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > > > > > > > > -- > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

> ~ the guard has to 'check-in' at various check points (there are four of >them, I was thinking about using long range remotes with a receiver in the >guard room. The guard has to check-in, in a sequence, so that he cannot >stand in one place and 'press the button' four times.) > ~ Once the guard has completed his patrol, he has to 'reset' the system >by pressing a button inside the guard room. How about each check in station and the ID unit the guard carries each have a serial number device such as a Dallas i-button in it along with an RTC. To check in the guard holds his ID device against the check in point device at which point they exchange serial numbers and log the time of exchange. This would be done through an RFID type technique. When the guard gets back to the guard room he holds his ID device against the guard room check in point, and serial numbers are exchanged again. This does the 'reset' of the system. Once this is done, the guard room point then downloads the log from the guards ID device, thereby providing an auditable log of times and check ins. There is also some sort of connection from the check in points to signify that a check in was made, but not carrying the serial number info, although it would need to signal that it was a valid serial number. These contact times are checked against the downloaded log to see that they were done in correct order. Perhaps too complicated for what you are trying to do? -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> How about each check in station and the ID unit the guard carries each have > a serial number device such as a Dallas i-button in it along with an RTC. To > check in the guard holds his ID device against the check in point device at > which point they exchange serial numbers and log the time of exchange. This > would be done through an RFID type technique. Hmm. So a group of thieves would only need to surprise the guard on his rounds, tie him up somewhere, then have one guy walk around as usual with the ID tag. Meanwhile the rest of the gang has all weekend to clean the place out. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, EraseMEolinspamspamBeGoneembedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

>Hmm. So a group of thieves would only need to surprise the guard on his >rounds, tie him up somewhere, then have one guy walk around as usual with >the ID tag. Meanwhile the rest of the gang has all weekend to clean the >place out. Which is why he needs to use it to log in at the guard house at the end of the round. If he does not then an alarm should be raised to the security company premises as originally mentioned. If the gang can get into the guard house to do this then there is a problem in the way the system is implemented which is beyond any logging system. If the ID unit is used as a key system to gain access then that is also a security flaw unless used with some sort of PIN system. It may be that using a PIN number at each logging point would help with any security problem, but this is still not a total solution. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

>Hmm. So a group of thieves would only need to surprise the guard on his >rounds, tie him up somewhere, then have one guy walk around as usual with >the ID tag. Meanwhile the rest of the gang has all weekend to clean the >place out. Heh, good thought. Why not implement a biometric ID system? Well... then I suppose you could cut off his finger or eyeball to use it for the ID... but you'd have to have quite the stomach for that one! Any system can be defeated, it's just a matter of to what lengths/risks you're willing to go to do it. --Andrew _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

>I do not know about the signal to the control room, >but i suggest that you use a battery powered pic >for the guard. he carries it around and plugs it into the various stations, >which will have different pins shorted inside the connector. The portable >pic can keep track of the guard's route. This will save you >transmitters or wiring. The problem with doing this is there is no feedback from the check point to the guard house, so you get no "timeout" until the guard gets back to the guard house. If the guard gets tapped on the head before the first check point, then the burglars have the whole round time plus the "timeout" period to do their business. If there is contact from each check point back to the guard house, then this time can be considerably shortened, and corrective action taken if need be. The other problem with this arrangement is that it requires physical contacts between the check point station and the guard's unit. If this can be done using an RFID system then no physical contact is needed. If no contact is required with the guard house then a system like that used by store security systems to stop stock going out the door could be used, where the check point station has a tuned circuit like gets attached to items in a shop, and the guard's unit detects this. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Alan B. Pearce wrote: > > >Hmm. So a group of thieves would only need to surprise the guard on his > >rounds, tie him up somewhere, then have one guy walk around as usual with > >the ID tag. Meanwhile the rest of the gang has all weekend to clean the > >place out. > > Which is why he needs to use it to log in at the guard house at the end of > the round. If he does not then an alarm should be raised to the security > company premises as originally mentioned. If the gang can get into the guard > house to do this then there is a problem in the way the system is > implemented which is beyond any logging system. If the ID unit is used as a > key system to gain access then that is also a security flaw unless used with > some sort of PIN system. > > It may be that using a PIN number at each logging point would help with any > security problem, but this is still not a total solution. Maybe a bar code attached to the Guard, ie ink stamp on the forearm, could be checked at each station. Maybe in conjunction with a new pin number for that day?? Keep in mind that any "key" devices can be removed from the guard, even "knowlege" systems can be compromised if they interrogate the guard. All you can do is make it more complex to hack the system. I watched the mafia movie "Goodfellows" the other night, they paid off the guards and got tips and passwords that way. Extremely easy. So how much do your guards take home each week?? Any of them got mortgages?? Are they willing to "look the other way" for $5,000 in cash, etc?? :o) -Roman -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

This could be a problem, any ideas to get around this? Richard ----- Original Message ----- From: "Olin Lathrop" <RemoveMEolin_piclistKILLspamEMBEDINC.COM> To: <PICLISTSTOPspamspam_OUTMITVMA.MIT.EDU> Sent: Wednesday, April 18, 2001 1:49 PM Subject: Re: [PIC]: Need some help with a PIC monotoring system > > How about each check in station and the ID unit the guard carries each > have > > a serial number device such as a Dallas i-button in it along with an RTC. {Quote hidden}> To > > check in the guard holds his ID device against the check in point device > at > > which point they exchange serial numbers and log the time of exchange. > This > > would be done through an RFID type technique. > > Hmm. So a group of thieves would only need to surprise the guard on his > rounds, tie him up somewhere, then have one guy walk around as usual with > the ID tag. Meanwhile the rest of the gang has all weekend to clean the > place out. > > > ******************************************************************** > Olin Lathrop, embedded systems consultant in Littleton Massachusetts > (978) 742-9014, spamBeGoneolinSTOPspamEraseMEembedinc.com, http://www.embedinc.com > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

hmm, that's a good idea. Something to think about. Richard ----- Original Message ----- From: "Craig Cassin" <KILLspamcraigcasspamBeGoneJPS.NET> To: <EraseMEPICLISTEraseMEMITVMA.MIT.EDU> Sent: Wednesday, April 18, 2001 5:11 PM Subject: Re: [PIC]: Need some help with a PIC monotoring system > I do not know about the signal to the control room, > but i suggest that you use a battery powered pic > for the guard. he carries it around and plugs it into the various stations, {Quote hidden}> which will have different pins shorted inside the connector. The portable > pic can keep track of the guard's route. This will save you > transmitters or wiring. > > -Craig > > ----- Original Message ----- > From: "Richard" <@spam@richard@spam@spam_OUTCCTGLOBAL.VIRTUALAVE.NET> > To: <spamBeGonePICLISTKILLspamMITVMA.MIT.EDU> > Sent: Tuesday, April 17, 2001 12:21 PM > Subject: [PIC]: Need some help with a PIC monotoring system > > > > Hi everyone. > > > > I need to build a system for me to monitor my guards. What I need this > > system to do is: > > ~ every hour (or 1/2 hr) notify the guard that he has to patrol > > ~ the guard has to 'check-in' at various check points (there are four > of > > them, I was thinking about using long range remotes with a receiver in the > > guard room. The guard has to check-in, in a sequence, so that he cannot > > stand in one place and 'press the button' four times.) > > ~ Once the guard has completed his patrol, he has to 'reset' the > system > > by pressing a button inside the guard room. > > ~ If the patrol was a success (there where no problems and the guard > > checked-in in the specified time limit) then the system must notify the > > control room which is located at different premises, either by radio via a > > repeater or through telephone lines using a tele-dialler, that the patrol {Quote hidden}> > was successful and that all is ok. > > ~ If something happened on the patrol (if the time limit expired or > the > > guard pressed his panic remote) then the system must notify the control > room > > that there is a problem and that someone must be sent out to the site. > > > > Firstly, what is the best way to get the signal to the control room. If > the > > system sends and audio signal (through the use of a voice chip) with a > > pre-recorded message or some form of data. If it is data, then something > > must be at the receiving end to decode it, maybe a PC running a program > > which answers a modem upon detection of a ring and then decodes the data, > > this will require some programming skills which I mostly lack. But can it {Quote hidden}> be > > done? > > > > Also what PIC would be most suited to this? Could it be possible to use a > > 16f84? > > > > I would appreciate any help that you guys can give. > > > > Thanks, > > Richard > > > > -- > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

At 07:42 PM 4/18/01 +0200, Richard wrote: >This could be a problem, any ideas to get around this? Sounds like the old DTex watchclock scheme, but with "smart keys". One possible bit of security you could add, is that they have to be punched in some particular order. Guards deal with this all the time. You have stations that you have to check hourly, some twice a shift, and some once a shift. Most guards will fall into a pattern anyway. You can dictate that pattern and you can detect variances from that pattern. -- Dave's Engineering Page: http://www.dvanhorn.org Where's dave? http://www.findu.com/cgi-bin/find.cgi?kc6ete-9 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> > > I watched the mafia movie "Goodfellows" the other night, > > they paid off the guards and got tips and passwords that > > way. Extremely easy. So how much do your guards take home > > each week?? Any of them got mortgages?? Are they willing > > to "look the other way" for $5,000 in cash, etc?? > > :o) > > -Roman More common than you might think. However, a smart operator will have a weak link, closely monitored. I used to do a similar approach on alarm systems. Bell box on wall, with wire running up outside wall.. Don't cut that wire! Bell box is empty, but the wire is an input to the system. Same on keyswitches. I'd use a cheap keyswitch and LED plate outside. The LEDs are active, but the keyswitch being turned just trips the system. The real control is a digital pad inside, where you have to trip a sensor to get to it. If you give them a not-too-obvious "easy-in", they'll usually use it. :) The control box should be put in a non-obvious location, since a fire axe will disable most systems pretty effectively. -- Dave's Engineering Page: http://www.dvanhorn.org Where's dave? http://www.findu.com/cgi-bin/find.cgi?kc6ete-9 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> ~ the guard has to 'check-in' at various check points (there are four of >them, I was thinking about using long range remotes with a receiver in the >guard room. The guard has to check-in, in a sequence, so that he cannot >stand in one place and 'press the button' four times.) Can you use a cell phone? Each check-in location would be a "thing" that matches the accessory connection on the phone. When you plug the phone into it, it'd dial a pre-programmed number and send appropriate encrypted/timestamped data string using appropriate data technology (or even touchtones, I guess.) The "emergency" function is probably already provided by the phone (dial a programmed number when you hold the 9 key for five seconds on my nokia, I think.) Depending on ecconomics, you can let the guards keep the phone as a perk... (all this solves is the communications issue. Most of the watchman's clock things I've seen that look like they might have instantaneous communications look like they're designed to have wiring in the wall - quite an expensive proposition for a (perhaps temporary) customer.) BillW -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Richard wrote: > > This could be a problem, any ideas to get around this? > > > How about each check in station and the ID unit the guard carries each > > have > > > a serial number device such as a Dallas i-button in it along with an > RTC. > > Hmm. So a group of thieves would only need to surprise the guard on his > > rounds, tie him up somewhere, then have one guy walk around as usual with > > the ID tag. Meanwhile the rest of the gang has all weekend to clean the > > place out. OK, what about a hidden system, like a RF ID unit hidden in the guard's clothes. Then make him visibly press a key code also. Thieves watching would see the key code and may even get that by interrogating a guard. But when they try to use it, the RF ID tag is not present and the alarm goes off. Many good alarms feature an obvious system combined with a hidden system, for this reason. :o) -Roman -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.