Galaxy G2 and Raspberry Pi

[ShaunShep]

we have an ex ADT alarm system installed.

As its no longer monitored And the system doesn't have an external bell box, I would like an easy way to know if the alarm has sounded when armed.

I have a couple of raspberry pi and wondered if anyone had wired one of these up to receive notifications to its GPIO pins? If it's possible then I wonder if you can read the data and do something with it?

Another option I was thinking of was tapping into one of the cables to the really loud internal speaker, and having a raspberry pi zero listen for voltage on one of it pins, and when detected do something? Like send an email or text message? Does anyone know how much voltage goes to this speaker when it's ringing?

I know services such as self mon exist, but this is more of a project really.

I have programming experience in Java, so figured it shouldn't be too difficult to knock something up. Ideally it would be great if I could log everything from the alarm system into a locally hosted Sql database, or even integrate it with Apples HomeKit to arm or disarm the alarm from my watch (Siri). but just detecting that the alarm is going off would be fine.

 

[GalaxyGuy]

I've helped out a couple of people to connect a Pi to the G2 trigger lead. The G2 doesn't have open collector output options, so you need to add a resistor on the trigger outputs to 0V in order to pull the already pulled up voltage down to 3.3V. If you don't do this, and connect directly to the Pi's I/O, you will damage the input and cook your Pi.

The speaker is also 12V.

I have a diagram somewhere, so will post it at some point when I get a minute.

The benefit of the SelfMon service with the LCE module is that it gives much more detail about the events than a trigger output ever could. I understand that people like to hack though

 

[ShaunShep]

Thanks, I had intended to put something like a voltage regulator on the speaker wire to drop the voltage down to 3.3v (from 12v) so that it's suitable for the Pi. If there's a trigger lead, then of course I guess it would be better to use that.

 

[GalaxyGuy]

I think the speaker will be too complicated. You'd need to step the AC speaker voltage down, feed into ADC, then take FFT's to determine between exit tones and alarms Etc. The trigger outputs provide easy programmable outputs.

Here's the wiring:

Rasp_trig

• GalaxyGuy
• 12 Sep 2016

Voltage divider circuit for pulled up Galaxy G2 trigger outputs.

 

[ShaunShep]

Thanks for that. When the alarm is triggered I'm guessing the output of the trigger will rise and be able to be picked up on one of the Pi's IO pins?

 

[GalaxyGuy]

The output will switch from 3.3v to 0v when triggered. The relevant bits on the I/0 will switch from 1 to 0.

 

[ShaunShep]

I appreciate your input, thanks.

I'm a little handy with home electrics but I'm struggling with the wiring diagram and wondered if you could explain the wiring diagram for me?

I can see that I need a 3k and 1k resistor, so that bit it fine.
Let's say I want to detect when the alarm is sounding. I can see that output 0003 is intruder, so let's say that's the pin I'm going to use. How would I wire this up to the Raspberry Pi? The wiring diagram looks like there's two connections to the trigger?

Correct me if I'm wrong (which I will be), I was under the impression it might be a case of connecting a cable from trigger 3 (0003) to an GPIO pin on the raspberry pi (via a resistor) and then write a program to detect a change on that GPIO pin? or do I have to connect up the 12v pin on the trigger header, and to the relevant pin number, and that's the two connections to the trigger I can see in the diagram?

EDIT: Actually, looking at the wiring diagram again I think it's just clicked. I need to connect to the 12v output (o/p) with a 3k resistor. Then a connection from the relevant pin on the trigger header to the Pi with a 1k resistor between the output and the relevant pin. If this is correct, which pins on the Pi can I connect up the 12v output and the output from the relevant header pin? Which one would I monitor to detect a change?

Just to note, I fully understand that the Pi cannot accept more than 3.3v on it's GPIO pins, so I would never just connect the 12v output directly to the Pi.

I've also noticed that according to the manual that it looks like by default the output from the pins is positive, dropping to 0v when active? Is that correct. I also see there's a setting on the system to alter to polarity, they're currently set to positive.

I know I'm probably asking loads of questions here.

 

[GalaxyGuy]

The diagram shows a single trigger output connected, say Trig 3. The second connection at the bottom to the trigger header is a common ground or 0V. This 0v connection needs to be common between the Panel and the Raspberry Pi, or the Pi will have no common reference for the trigger voltage coming from the panel.

You will not be able to power the Pi from the header. The header only supplies 100mV at 12V and even stepping this down efficiently would not give you the 1A @5v that you'd be looking for to power the Pi.

As per my previous post regarding the output polarity - the output defaults are switched negative. They will go from a positive voltage and drop to 0v when active. As you've found in the manual, they can be programmed to switch positive. You can always handle that at the Pi programming side too.

 

[ShaunShep]

Can the ground be connected to a ground pin on the Raspberry Pi? Something like this? (excuse my crude drawing).

 

[GalaxyGuy]

Yes. The other way to do this is to opto-isolate the connection or use relays, but that requires other devices. Most people with Galaxy panels have a few 1k resistors hanging around.

 

[ShaunShep]

I was just about to ask about the 3k resistor and I couldn't easily find any, and did wonder if I could wire three 1k resistors together, which you've asked.

Thanks again for all of your help, I fully understand what needs to be done now.

I plan to wire triggers up to intruder, set and unset. I think I'm going to integrate with Apples Homekit so I can ask Siri if the alarm is set, and have it tell me if it's set or not. It would be great if there was an easy way to set/unset the system but I guess for security reasons there isn't, or I could have also setup Homekit to set and unset the alarm. "Hey Siri, set the security system".... beeeeeeeeeeeeeeeeeeeeeeeep.

It may be possible to have homekit notify me when the alarm is set, unset and triggered, which would be especially good as I'd get these notifications on my Apple Watch. But we'll see, I need to understand fully how the Homekit integration works which I'm doing in a project at the minute which involves our central heating, wireless thermostat and a java based HAP server.

 

[unclebob1]

Just a thought - would openGalaxy (https://sourceforge.net/projects/galaxy4linux/) work with the g2? Im aiming to setup the pi taking input based on reading it back from a mysql database.

 

[ShaunShep]

According to the documentation...

"Galaxy security panels have always been backwards compatible (with the exception of G2 panels). The oldest class of panels are now called XL (or classic) panels and the new ones G2, G3 and Galaxy Dimension (GD)."

No idea if that means it will work or wont.

 

[GalaxyGuy]

No, the G2 doesn't support the rs232 module. I don't think the open galaxy project have any support for IP modules yet.

 

[unclebob1]

Fair enough. Wasn't sure on comparability!