interfacing a wireless alarm system

[den372]

Hi, I am looking for wireless rf contacts that can be used for door and window sensors. I would like to monitor them with an rf receiver that would use the same frequency and message protocol. My concern is that any commercial products will use a proprietary format and may not be easily integrated into a breadboard project. ( I am not sure). I was planning on using a micro controller to decipher the message and determine alarm status. Has anyone tried this. I was hoping to find door and window sensors that can be purchased. As a brute force approach I was thinking of monitoring the siren voltage of a commercial system and then send out notification thru a PC, send email, call cellular, etc. Unfortunately this would not indicate which zone was breached. Any help on this matter is greatly appreciated.

 

[Ross Craney]

Are you are only worried about alarm status? All quality alarm systems will have programmable o/ps which can be used to indicate alarm status. If you want more in depth information then monitor the dialler o/p & decode that. It will most probably be DTMF format Contact ID protocol. Info about Contact ID is freely available.

 

[Birdman Adam]

You might try working with one of these:

DSC Wireless Door/Window Transmitter

My house uses these with it's security system for monitoring windows or doors. It transmits at 433 MHz. Basically it sends out a signal whenever the door/window opens, closes, or it senses someone taking the cover off it. It also says 'hello' to the receiver every 20 minutes so the system can tell if someone is jamming the Tx. Each Tx has it's own unique address. Whenever one of the above actions happens, it sends out it's address, along with data about what's happening. This should be fairly easy to listen to with a receiver built for 433 Mhz.
If you didn't want to try to decipher with a reciever, you could by the wireless module made by DSC for the security system and listen to what it says about the Tx's through the Keybus.

 

[Ross Craney]

You might try working with one of these:

DSC Wireless Door/Window Transmitter

My house uses these with it's security system for monitoring windows or doors. It transmits at 433 MHz. Basically it sends out a signal whenever the door/window opens, closes, or it senses someone taking the cover off it. It also says 'hello' to the receiver every 20 minutes so the system can tell if someone is jamming the Tx. Each Tx has it's own unique address. Whenever one of the above actions happens, it sends out it's address, along with data about what's happening. This should be fairly easy to listen to with a receiver built for 433 Mhz.
If you didn't want to try to decipher with a reciever, you could by the wireless module made by DSC for the security system and listen to what it says about the Tx's through the Keybus.

He's worried about de-cyphering a proprietory format.

 

[den372]

Thank You all for the responding to my question. As far as actually trying to decipher the message, I have read that several companies encrypt the message for security reasons. I think that trying to crack the encryption algorithm used by some of these vendors may be out of my league. Monitoring the dialer is a good idea, unfortunately we do ont have a lan line. It has been my observation that most if not all the systems out there require a monitor fee. I want to get away from that.

 

[Ross Craney]

Thank You all for the responding to my question. As far as actually trying to decipher the message, I have read that several companies encrypt the message for security reasons. I think that trying to crack the encryption algorithm used by some of these vendors may be out of my league. Monitoring the dialer is a good idea, unfortunately we do ont have a lan line. It has been my observation that most if not all the systems out there require a monitor fee. I want to get away from that.

They only require a monitoring fee if you subscribe to a monitoring centre. 95% of security systems have an inbuilt dialler as standard. During setup programming this dialler can be programmed to ring any number , it does not have to be a monitoring centre. All the information you require will be available from the dialler. For it to work you will have to be able to simulate handshake & kissoff tones etc.

 

[Birdman Adam]

Ross is right. The problem is that after an alarm is installed in a house, and the homeowners decide to have the security guys come out and monitor, (ADT, CPI, etc), they program the system to call out to their monitoring companies' alarm phone lines. Once they set it up to do this, they usually lock out the homeowner from doing anything with their alarm by setting an installer code that only they know. Unless you know the code for your alarm system, or its' still the default, you cannot configure your system as you please. Other option is to do a full reset, but they can prevent that too.

Now assuming that your system hasn't been 'stolen' from you by security guys, and you know the installers code, you can program your alarm as you please! Almost all systems come with a dialer. On many systems, (like the DSC Power832 in my house), you can set it to call any #. I have it set for my cell. There are a few options for the type of call, and if you wanted it to call your cell, you can just set it for 'pager'. Then if an alarm goes off, the system calls you, and when you pick up, you will hear a series of beeps that tell you what zone is open. You dont have to actually have a phone line connected to the dialer, it will still try to call out. If you monitor the dialer, then whenever it calls out you would know you have an alarm.

**broken link removed**
This is a great place to start and they have the installers manuals for changing setting in almost all alarm systems.