HotFries
Posts: 3
Joined: Tue Dec 11, 2018 2:31 am

Alarm System using existing DSC wiring

Tue Dec 11, 2018 2:41 am

Hi All,

I have spent hours and hours trying to find a workable article on building a Raspberry Pi alarm system. All of them were failures because the code wouldn't run or there was incomplete information.

Did anyone make a RPi security system?? I have a DSC and looking to connect the sensor wires to the GPOs of the RPi.

Thanks

ref
http://homealarmpluspi.blogspot.com/
https://blog.adafruit.com/2015/07/17/ma ... pberry_pi/
and many more...

pcmanbob
Posts: 6646
Joined: Fri May 31, 2013 9:28 pm
Location: Mansfield UK

Re: Alarm System using existing DSC wiring

Tue Dec 11, 2018 11:15 am

Hi.

Unless you find an example build using your exact alarm system you may well find the examples you have found will not work, any build requires you to have some input to make it work when adapting an existing system.

May be if you gave us more detail of the existing system and how its connected then we could help , just saying its DSC means nothing.

if you have tried examples you found on the web did you contact the writer to see if they could help with code problems ?
We want information… information… information........................no information no help
The use of crystal balls & mind reading are not supported

HotFries
Posts: 3
Joined: Tue Dec 11, 2018 2:31 am

Re: Alarm System using existing DSC wiring

Fri Dec 14, 2018 12:41 am

It's a dsc 832 pc5010.

Just brought a house and it's an existing system. I'm pretty sure it's not working. The owner did not give me a code for it. So it just sits there flashing some lights. I did get an estimate from a DSC professional and he said that the system is pretty old and would cost $800 to upgrade and setup.

All I want is to send me an email when the door circuit is closed. I'm sure Pi3 can do that. If I get a app UI - that's a bonus.

PhatFil
Posts: 1342
Joined: Thu Apr 13, 2017 3:55 pm
Location: Oxford UK

Re: Alarm System using existing DSC wiring

Fri Dec 14, 2018 1:37 am

what features do you want need? what sort of inputs are there for the current alarm? and at what voltage do they operate?

for example a PIR sensor may operate at 12v+ and fail to run at all if the supply is any less, A 12V signal connected to a pi gpio would fry it.
however other sensors such as door/window open alarms may be simple magneitc contact switches which could run quite happily on a 3.3v or 5v signal (distance and grade of wire will dictate any voltage drop if any..)

pcmanbob
Posts: 6646
Joined: Fri May 31, 2013 9:28 pm
Location: Mansfield UK

Re: Alarm System using existing DSC wiring

Fri Dec 14, 2018 10:41 am

If you want the pi to replace the alarm panel you are going to have to do a lot of on site testing to determine how the various alarm contacts/pir's are wired and then work out how to interface this existing wiring to the pi gpio with the required voltage level shifting as required.

A typical switch contact circuit might have 4 wires 2 for the alarm 2 for a tamper circuit, were as a pir circuit might have 6 again 2 for alarm , 2 for tamper and 2 for power, you need to sort all this out and draw up diagrams with existing voltages included ,

then you can decide which circuit can be changed to 3.3v working ( 5v will probably be better because of the cable lengths but will required a level shift ant the gpio from 5v to 3.3v )

any pir circuits will need to keep the 12v to power the pirs but again you can change the alarm/tamper circuits to match the pi.

once you have all this sorted out the actual programming is not that difficult you only need to test each circuit to see if its intact and any that any will trigger the appropriate response ( bell, email etc) .
We want information… information… information........................no information no help
The use of crystal balls & mind reading are not supported

drgeoff
Posts: 9743
Joined: Wed Jan 25, 2012 6:39 pm

Re: Alarm System using existing DSC wiring

Fri Dec 14, 2018 6:50 pm

Judging by the words "using existing DSC wiring" in the title he chose the OP has come to the conclusion, probably correctly, that the existing wiring is the most useful part of the current installation. Installing the wring tends to be the most time consuming part of a wired alarm system which is why so many systems use wireless.

Attaching remote switches to RPis via long wire runs is not as simple as one might expect. Proven by the steady appearance of posts such as viewtopic.php?f=28&t=228806 asking how to eliminate false triggers on long wires.

HotFries
Posts: 3
Joined: Tue Dec 11, 2018 2:31 am

Re: Alarm System using existing DSC wiring

Sun Dec 16, 2018 6:38 pm

luckily I'm an electrical engineer and am aware about float situations on pins.

I'm going with the off-the-shelf eyes-on solution. It'll save me a lot of headache and is the quickest way to get it up and running fast.

Thanks all

jerryk
Posts: 30
Joined: Wed Nov 02, 2016 3:26 pm

Re: Alarm System using existing DSC wiring

Sun Dec 16, 2018 6:42 pm

I started on a similar project two years ago. The initial concept was helped along by this forum in this thread (viewtopic.php?f=37&t=164662&p=1069577#p1069577). You can take a look and see if it helps further what you are trying to do.

The hardwired loops that connect the various windows and doors in my house run through a voltage divider at the panel. So with a 12V system closed door switch reads 6V at the input terminal and when the door switch opens it reads 12V. I set a reference voltage of 9V and used a comparator to detect when the input voltage was above or below the 9V. That's it in a nutshell.

Eventually I migrated from the breadboard to a printed circuit board designed in Kicad and the final product looks like this.
small-3201.jpg
small-3201.jpg (243.43 KiB) Viewed 3458 times
Hope this helps - Jerry

PhatFil
Posts: 1342
Joined: Thu Apr 13, 2017 3:55 pm
Location: Oxford UK

Re: Alarm System using existing DSC wiring

Mon Dec 17, 2018 12:22 am

HotFries wrote:
Sun Dec 16, 2018 6:38 pm
luckily I'm an electrical engineer and am aware about float situations on pins.

I'm going with the off-the-shelf eyes-on solution. It'll save me a lot of headache and is the quickest way to get it up and running fast.

Thanks all
Probably the best way to get a system installed quickly and trouble free..

Meanwhile you can cogitate on and plan the ideal system you can diy in your own time without any pressure. If so inclined, it is an ideal learning project.

maurice1
Posts: 37
Joined: Tue Mar 05, 2013 8:55 am
Location: Dublin

Re: Alarm System using existing DSC wiring

Thu Dec 20, 2018 1:58 pm

I Have an existing 10 Zone Aritech alarm system which works fine but I wanted the email remote set/unset and SMS if it went off.
I found the easiest way was to use an arduino nano plugged into the pi by USB.

1.This gives the analog inputs that most alarms need for inertia sensors on the windows and doors so the alarm goes off before intruder gains access. Initially I did try the MCP3008 route on the pi but the arduino was more reliable

2.Takes care of the 5v that my alarm sensors run at, compared to Pis at 3.3v

3. Running for a couple of years and no problems.

I used to find that if left for months it got dozy so now it sends an email when the hall door is opened.

Piserial reads the analog readings from the pi and processes it via python.

I have a couple of PIRs over 2 circuits . Using different resistor values If I get an SMS it tells me which PIR triggered using the existing wiring.

The pi also runs the home automation.

Handy thing about a pi in your alarm box is the 12v (stepped down to 5vdc) rechargable battery so the pi wont suffer during power outages.
I also have a CAT5 going to the alarm box .

I also built in a test feature so when I test a zone I get an email immediately, saves walking back to the alarm box.

Before you start it may be an idea to test each cable/detector and check and mark its resistance if your alarm uses an EOL system. "End Of Line" resistor, common in Europe

kmc123
Posts: 1
Joined: Sat Dec 29, 2018 4:26 pm

Re: Alarm System using existing DSC wiring

Sat Dec 29, 2018 4:32 pm

@jerryk - Would you share the eagle files or Kicad files? I'd love to do this at my house! Any code that you can share? Thanks in advance!
@maurice1 - Same question for you as far as the code goes. You two sound like you've really got the head start on this!

Thanks guys!!!

jerryk
Posts: 30
Joined: Wed Nov 02, 2016 3:26 pm

Re: Alarm System using existing DSC wiring

Mon Dec 31, 2018 8:49 pm

Here is the schematic of what I did to interface with my old school existing system. I'm not sure there is any generic solution to be had out there and there was a lot of reverse engineering of the existing system to solve the problem at hand. Hacking the keypad was the most difficult in that it uses serial communication to send each keypress and I had to understand that first, which took some head scratching. In the end it was simple binary sequences sent by each button on the pad to the main panel and all I did was make an interface to simulate the same. Not all keypads do this and some are easier to crack than others.

Take a look at the schematic and see if this will fit your existing system. If so I'll see if I can dust off the kicad files and post them.

Jerry

added a link to schematic for readability : https://drive.google.com/open?id=19SVl5 ... DjDgwfbbtK
Attachments
alarm_shema_final-1.jpg
alarm_shema_final-1.jpg (191.85 KiB) Viewed 1907 times

Northern Mike
Posts: 40
Joined: Mon Oct 31, 2016 11:41 am

Re: Alarm System using existing DSC wiring

Fri Jun 28, 2019 6:40 pm

I know this is an older thread, but I just stumbled on it.
I am an alarm installer, specifically DSC products. If you are looking to use the individual zones from your older 5010 system, there are a couple things you need to confirm.
First off, looking at only wired zones, contacts and motion detectors are either 'normally closed' (most common), normally open (less common), and either NO or NC with end of line resistor (least likely with residential).
Assuming that all contacts are Normally Closed (NC), you could use the GPIO to check if the zone or pair of wires are closed (normal) or open (alarm state).
Most motions require 12VDC to operate and will show as being open if they are powered down.

Once you have assigned the GPIO pins to the zones, a simple monitoring of these pins and notification if change is all that appears to be needed.

On the wiring of the existing 5010 board, the zones are fairly easy to identify, with one wire of the pair going to a "C" or common terminal. Generally the wires of a 4 wire quad wire use yellow and green for zones, black and red for power (if needed).

I hope this makes sense. Its pretty simple but could look scary depending on how messy the tech was that did the installation.
There can also be expander boards if your system needed more than 8 zones. These boards also work in 8 zone configurations (on 5010) and are about the size of a RPI zero.

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