• it's all about Connection

    oni305 • 05/01/2019 at 20:21 • 0 comments

    The backbone of the entire system will be the ability to connect the various node, in the need of identify the best way to do so, i have selected five alternatives:
    > KNX
    > CAN
    > DALI
    > WIFI/RF
    > Developing a proprietary protocol based on DALI and CAN

    (+) Pro
    (-) Cons

    KNX (TP)
    - requires complex power supply
    - little choice of transceiver ICs (more expensive)
    + only 2 wires for bus and power supply
    + multimaster
    + line/bus, tree and star topology are allowed

    CAN
    - requires 4 wires, two for power and two for the bus
    - only line/bus topology
    - requires termination resistance
    + multimaster
    + cheaper transceivers

    DALI
    - Manchester encoding
    - master/slave (dali 1)
    + only 2 wires for bus and power supply
    + simple power supply
    + the interface is realizable with passive components
    + line/bus and star topology are allowed

    WIFI/RF
    - requires power supply (mains)
    - not good if is inserted inside the wall
    + simple to implement + tree, star and mesh topology are allowed

    Developing a proprietary protocol based on DALI and CAN
    (HW interface based on DALI protocol based on CAN)
    - everything needs to be developed (HW & SW)
    + only 2 wires for bus and power supply (DALI)
    + simple power supply (DALI)
    + the interface is realizable with passive components (DALI)
    + line/bus and star topology are allowed (DALI)
    + mltimaster (CAN)

  • First log, first block ...

    oni305 • 04/10/2019 at 22:11 • 0 comments

    The first subsystem I'm working on is the light control.

    It is possible to have two cases:
    1) more than one control per light point
    2) a single control for light point

    To ensure that it is possible to drive the light from any switch the node must behave as a 4 way switch.

    The first case is the simplest, it is sufficient to connect the node in series to the switches [1].

    The second case is slightly more tricky, it is necessary to replace the single switch with a 2-way switch and put it in series with the node [2a], or with a push-button connected directly to the node [2b].

    The "SWITCH NODE" must have three functions:
    - switch ON/OFF the load
    - sense if the load is ON or OFF
    - communicate to receive commands and send the status of the load