Struggling to integrate alarm receiver / sensors with Arduino-based system

Projects Networking, Protocols, and Devices
1

Hi,

For a bit of background: I've built an Arduino-based prototype system, using a single Uno w/Ethernet shield, 5 eBay-type PIRs hooked up to Nanos and then 315Mhz transmitters to get data back to the main Uno unit from around my house. Basically this is all working fine, but I want to mimic the same functionality using standard off the shelf burglar alarm components - I've attached a basic diagram summarising what I'm trying to achieve (arduino_alarm_kit.pdf).

After doing quite a bit of research and finding some tutorials about interfacing an Arduino with existing alarm systems, my challenge is clearly different to what most people are doing as they're either a) interfacing with an alarm motherboard itself, b) interfacing with hard-wired sensors or c) building a completely custom Arduino-based system (have already done this).

My challenge is I want to use a single (non-Arduino) receiver to get signals from multiple sensors and then pass this across to the Arduino Uno so I can upload it to my web service. Most of these wireless PIRs appear to use some sort of encryption for security so from what I can see I just just use the standard 315Mhz receivers to get this data. In addition I'll be able to read things like tamper values all things going well.

I ordered the following hardware, figuring that a receiver that has been designed for 'hard wired' alarm systems should be easy enough to integrate with the Arduino:

Receiver:

Sensors:

I've got the sensors enrolled to the receiver and it's LED goes on whenever one of them triggers so I can see that's all working. Having done some reading and looking at the documentation for the receiver (also attached) it appears as though the types of sensors i want to use have a 'normally closed' circuit, while the transmitter has outputs for N/C, C, N/O.

I've also put the multimeter on all three of the receiver outputs (N/C, C, N/O) but can't see the voltage changing at all. It's all a bit odd as the LED does activate on this unit so things are definitely happening.

I'm just really stumped as to how I could read this data into my Arduino. I don't really want to have to use an alarm motherboard and then read off that as from what I can see the receiver would just be hard-wired to one of the input zones.

Thanks in advance for any assistance.
David

arduino_alarm_kit.pdf (106 KB)

MCR-304.pdf (310 KB)

2

5 eBay-type PIRs

What the heck is an eBay type PIR? Is that somehow different from a PIR sold be a reputable supplier?

Most of these wireless PIRs appear to use some sort of encryption for security so from what I can see I just just use the standard 315Mhz receivers to get this data.

To get the encrypted data, maybe. How are you then planning to decrypt it?

I've also put the multimeter on all three of the receiver outputs (N/C, C, N/O) but can't see the voltage changing at all.

The voltage with respect to what? I'd expect C and N/C to go from connected to unconnected and/or C and N/O to go from not connected to connected, continuity-wise.

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Hi - re: PIRs, I bought the first batch from eBay (from China) and the 2nd batch from a reputable supplier.. both look identical!

re: data encryption - from what I can see the receiver unit that I've paired these sensors to does all that. I'm working under the assumption that if its designed to extend a legacy 'hard wired' system then its going to pass on unencrypted signals/data as the encryption would only apply to the wireless traffic.

The voltage test was just to see if there were any changes when a sensor was triggered - not sure what I'd use to measure these changes/troubleshoot this situation?

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not sure what I'd use to measure these changes/troubleshoot this situation?

A continuity tester.

5

Just checked, behaviour is as you expected:

N/C + C : stops beeping on tester when sensor triggered
N/O + O : starts beeping on tester when sensor triggered