Using wired sensors



  • Hello,

    I just got out from under my rock and discovered your site 🙂 Pretty cool and lots of interesting things to learn. I have a newbie question (apologies in advance if this has been asked before): I have a lot of wired sensors in my house that I inherited with the house. I don't use the original security system but I would like to use the wiring to detect open doors/windows, motion, etc. I like the wired approach much better because 1) I don't have to worry about changing batteries (ever!) and 2) less radiation to bathe in 🙂

    My question: do you have support for the wired sensors? I was thinking it would be awesome if we can power them and send the sensor information over the same wires.

    Thanks in advance!

    Florin


  • Mod

    @florint welcome to the MySensors community!

    MySensors has support for wired sensors through rs485. See https://www.mysensors.org/build/rs485 for details.



  • @mfalkvidd Thanks for the quick reply! I love everything I've seen on your website! Really well done.
    RS485 seems promising. I would need to find some kind of gateway that can deal with lots of endpoints/sensors... Still searching through your website - a treasure trove of information for sure 🙂



  • I concur that RS485 would be the way to go for wired nodes. Being wired, the system should be VERY stable.


  • Mod

    It is stable if the cabling is done properly 😉



  • @gohan True. I have always used twisted pair cabling when wiring anything on 485 and haven't had any trouble myself, but other types of cable might have a different impedance and cause issues. Also, on some of the nodes he may need to remove the termination resistors.


  • Mod

    Or add them if not present. Bus communication is nice but you need to know what you are doing, working with electric signals isn't like powering a light bulb. Once I had to explain to an electrician that rj45 plugs needed to have a specific cable sequence and he could just make one plug identical to the other.


 

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