Existing Alarm System

[Tony]

Hello All,

I'm new to Raspberry Pi or programming for that matter. Anyway, I have an existing home alarm system at home that's been deactivated before I moved in. I don't want to pay monthly for someone else to monitor my home and then I stumbled upon this.
Is it possible to retrofit the old alarm system with Raspberry Pi and PrivateEyePi while making use of all existing components such as keypad by the door, sensor and reed switches, etc?
If yes, how could it be done?
I'd like to gather as much information as possible before playing around with it.

Thanks in advance!

[Gadjet Nut]

Connecting the door sensors is the easiest. PIR motion sensors depends on what you have and whether it behaves like a switch (most do). We don't support keypads. The Web app replaces the keypad. Setting up the system does not require programming knowledge just follow our step by step tutorials. Basic electronics knowledge is required to dismantle and connect your alarm.

[Gadjet Nut]

[Arthur Roberts]

I have an existing system as well.  Would it be possible to do something simpler as a first step, like just connecting the alarm output from the existing system to an input of the Pi.  I would just need the Pi to recognize that the alarm is sounding and then notify me through PrivateEyePi.  Or would it be overkill for PrivateEyePi to do something like this?

[Gadjet Nut]

Assuming you understand the electrical output from your alarm system, and can connect it to the Pi then yes that would be a possibility. However you would not get the granular monitoring and reporting from PrivateEyePi on all your sensors. 

[bradpjones]

My home had two different alarm systems.  An old wireless Roland Security and a hard-wired system.  I used sensors from both systems (removing the wireless modules and running cable) in my pep installation.  I've used some of the hard-wired runs to the old keypads to install temp sensors and plan on adding door chime and siren with them as well.  So, yes!  Just need an understanding of basic two-wire hookup.

[asher cohen]

For a similar project (connecting the buzzer cables output to a pep sensor) should I just follow the guide to build a pir sensor or what do you suggest?I assume that the voltage of the buzzer could damage the sensor,how can I protect it?

[Gadjet Nut]

What is the output voltage? You can use a switching transistor like NPN2222A or a relay switch to protect the buzzer, but you need to know first what the output voltage is. 

[asher cohen]

Output voltage is 12,5V if I am correct. I have bought a relay switch from your store so I would like to use that. Should i build the same sensor following the PIR project and put the relay in the place of the PIR or the scheme is different?

[Gadjet Nut]

12.5V should be OK to use on the relay switch which has allows input of 3V-12V. The NPN2222A should also work as it accepts up to 40V. . So if you use the relay switch then it will switch a circuit on the Raspberry Pi. You can use a pull up circuit as in the alarm system tutorial:

http://projects.privateeyepi.com/home/home-alarm-system-project/installation/alarm-electronics

So you will be replacing the reed switch in alarm system tutorial with your relay switch.

[asher cohen]

Ok then. I have seen the schematics but I am unsure to have understood.
-My existing alarm has a siren output (12v) that I have connected to the relay switch (on the pins side, as an input for the relay). I can see the relay switch on and off when the alarm triggers the siren.
- The screwed wires would go to the raspberry gpio (COM to ground and AO to an input port).

Problem is I get wavering state on the input pin so it does not understand if the alarm is on or not and the relay switches on only when the alarm triggers. Should I put a transistor bewtween the gpio and the relay?what transistor?
Is the circuit safe for the raspberry?

Thanks

[Gadjet Nut]

You need to construct a pull up circuity as described in this tutorial:

http://projects.privateeyepi.com/home/home-alarm-system-project/installation/alarm-electronics

Replace the green reed switch with your relay switch (COM to ground and A0 to the two resistors).How it works is when the relay switch open the GPIO is pulled HIGH as when the relay switch closes the GPIO will go low. 

[asher cohen]

Hello ...I have followed your instructions and I managed to build the resistor scheme. Now I can read the relay state from the gpio pis but sometimes the signal comes even if nothing happened really. do you know why?

[Gadjet Nut]

Need more information about your wiring and your sensors before anyone would be able to help you. 

[asher cohen]

I connected an old alarm system to a raspberry following your instructions:
- siren output of the alarm goes to a relay board.
-relay goes to pull-up circuit (followed the info from your link)
-pull-up circuit goes to raspberry pi pins.
Now the pull-up circuit works great but sometimes I receive multiple inputs from it. How can I read correct state only when it really triggers?

[asher cohen]

No news?

[Gadjet Nut]

Need more information on your wiring. Sounds like a wavering GPIO caused by insufficient pull up but without details on your wiring it's difficult to diagnose.