IVB\’s Home Theater and Home Automation

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How’s it all wired up?

Posted by IVB on May 9, 2006

Somebody about how the basic wiring/etc was done. I'm sure I got a ton of stuff wrong, but the basic theory I think is sound. Here's an example sensor layout according to how i'm doing it. [not my house, don't worry].

Also, on the how-to, I just got 2 training CDs from Elk in the mail today. I'm going to setup myhomeautomationpc.com as a holder for any salient content from end-users as to how they've setup their systems, and will be hosting the training content there.




3 Responses to “How’s it all wired up?”

  1. kwoodrow said

    How much – if any – of the security system can be done wirelessly? It’s simply not practicable for me to hardwire my door, window, motion, or smoke sensors. Can they be done wirelessly with the Elk? If so, what is needed on the Elk side to communicate with them?

  2. IVB said

    It’s certainly possible to do much of this wirelessly.If you go to the page i’m linking to at the end, you’ll see wireless smoke/glassbreak/door&window/etc sensors and receivers.

    I personally didn’t go down that route since:
    1) It is possible for me to hardwire
    2) It’s much much cheaper to do hardwired. on avg, wireless is $60 per sensor, as opposed to my 40-sensor avg of probably ~$15-$20. I doubt anyone would be as ludicrously covered as I am in a wireless situation since that would be 40 x 60 = $2400 just in sensors.
    3) Reliability (for me) – I have soooo much wireless in my house, plus power lines overhead, plus I live in a 95yr old craftsman with plaster/lathe so many wireless devices don’t work well there.


  3. IVB said

    Another wiring question came up offline about how it was wired up. Here’s the answer:
    You have 2 options when wiring sensors:

    1) Cheaper: Run sensors in series, where you daisy-chain the wiring from one sensor to another, and run back to the Elk main board. This means you’ll probably only need the main board, as it has 16 zones.

    2) More Granular info: Homerun each sensor back to the Elk. You’ll probably need some zone expanders based on the # of sensors you have. For example, I have about 40 sensors. The base Elk has 16 zones. As I’m running nearly all wiring to the 2ndary cabinet, I needed 3 zone expanders (IIRC, they’re about $70 each), as 16×3=48zones possible.

    I also bought the Data Bus Hub, which I’d highly recommend. That way I can plug each expander into the Hub, and run one wire from the hub back to the Main Board.

    For sensors, there’s 2 main types of sensors:
    – 2 wire. These are non-powered sensors, such as window contacts, that basically just open/close a circuit. For these you just run 18/2 or 22/2 back to the Elk [either main or expander]. The two wires are either N/O [normally open] or N/C [normally closed]. You specify which one in the ElkRP software. (see below)

    – 4 wire. These require power, such as motion sensors. You run your 2 zone wires as above, plus a 12V and neg wire. You can use a regular 18/4 for this as it’s low-voltage.

    The other thing to know is that you’ll probably want to terminate your sensors with a resistor. I’m still learning the details of why, but it’s basically to detect if the wires are cut [aka a burglar cuts the wires].

    BTW, A cool feature of the Elk is a rich recorded voice vocabulary. Check out the right side under voice description – that’s what you hear if this gets tripped while the Elk is armed. I just set that up – i could have just as easily picked another set of words to say.

    Here’s the ElkRP picture of the sensor type options.


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