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Optical or opto-electronic actions?

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  • Optical or opto-electronic actions?

    I've read about optoelectronics related to computing, but found nothing related to pipe organ actions.
    Why don't pipe organs use optical or optoelectronic actions?
    Correct me if I'm wrong, but fiber optic action may be more responsive than copper wire action, given that the optical fiber is longer than the copper wire. Would it use much power if converting optical to electronic signal?
    Suppose that when pressing a key, an optical signal is sent to a photoconductor to admit electric current to a magnet, either a lever magnet in the case of direct-electric action or a floating or hinged magnet in the case of electro-pneumatic action. Opto-electro-pneumatic action?
    Photoconductor would be a substitute for transistors and relays.
    Ever heard of power-over-fiber?
    Last edited by WorldQuestioneer; 07-20-2022, 12:11 PM. Reason: Add a condition to a sentence.

  • #2
    Modern pipe organ control systems communicate over an ethernet connection. Ethernet is cheap, reliable, and ubiquitous. There's no reason that an Ethernet fiber optic connection couldn't be used rather than a CAT cable, but there's no compelling reason to do so.
    -Admin

    Allen 965
    Zuma Group Midi Keyboard Encoder
    Zuma Group DM Midi Stop Controller
    Hauptwerk 4.2

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    • #3
      Many systems do use fiber optic but what has been found is that the systems work perfectly fine over cat 5, and cat cable is much cheaper, easier, and less finicky to install and use. Additionally, for example, the opus two control system only requires 3 wires to communicate between chambers and the console which means that with proper setup, you can even use old wires (say stop wires 1-3) and not have to run any new cable. The only major benefit to using optical that is still marketed for organ systems is that it is less prone to lightning issues. There may be other benefits but that’s is just what I can remember for now.

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      • myorgan
        myorgan commented
        Editing a comment
        John,

        For runs over 300' in a large church, how is the signal repeated–a simple router?

        Michael

      • johnroper100
        johnroper100 commented
        Editing a comment
        As far as I recall, no repeater. Remember that this is not a cat5 cable with an Ethernet port, this is simply 3 wires. They have the manuals available on their website.

    • #4
      I think I remember a Hauptwerk user that set up optical switches for their organ console. Apparently they worked quite well. However, They aren’t actually a lot faster than magnetic or wire contact actions, and light pollution is a problem (they had to enclose the whole assembly to prevent stray switch presses). So it’s possible, but probably not worth the extra effort.

      Another consideration is sending data over fibre optic cable. As mentioned before, usually you would only do this instead of wires if you need much higher band width, otherwise it’s just a lot of extra expense. The amount of data communicated by an organ is pretty small, so it probably isn’t worth it, but as mentioned, it does work.

      Current: Allen 225 RTC, W. Bell reed organ, Lowrey TGS, Singer upright grand
      Former: Yamaha E3R
      https://www.exercisesincatholicmythology.com

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      • myorgan
        myorgan commented
        Editing a comment
        In other words Larason2, fiber is an "overkill" solution for a problem that doesn't exist?

        Michael

      • Larason2
        Larason2 commented
        Editing a comment
        Yes, exactly!

    • #5
      I also thought, after starting the thread and before I saw the rest of the posts and comments... Doesn't the pressing of the key have to complete a circuit via contacts, to produce the light to go through the optical cables? Maybe light-emitting diodes would be best for that.
      Maybe optical cables provide better bandwidth, not much better latency. Latency is the time it takes for each bit/byte to reach the destination. Bandwidth is the amount of bits/bytes that can be passed a second.

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      • myorgan
        myorgan commented
        Editing a comment
        Originally posted by WorldQuestioneer View Post
        Maybe optical cables provide better bandwidth, not much better latency. Latency is the time it takes for each bit/byte to reach the destination. Bandwidth is the amount of bits/bytes that can be passed a second.
        I'm not sure bandwidth is an issue where Cat.5 can easily handle the on/off signals being sent.

        My only curiosity is if optical could provide more accurate velocity sensitivity than Ethernet.

        Michael

      • Admin
        Admin commented
        Editing a comment
        Ethernet is a network protocol, with independent physical layer. From Wikipedia
        The original 10BASE5 Ethernet uses coaxial cable as a shared medium, while the newer Ethernet variants use twisted pair and fiber optic links in conjunction with switches. Over the course of its history, Ethernet data transfer rates have been increased from the original 2.94 Mbit/s[2] to the latest 400 Gbit/s, with rates up to 1.6 Tbit/s under development. The Ethernet standards include several wiring and signaling variants of the OSI physical layer.
        I think even at the original 2.94 Mbit/s data rate there would be plenty of bandwidth making latency a non-issue. Standard MIDI data rate is only 31.25 kb/s and it can handle upwards of 1000 3 byte messages/second.

        Since the question was related to pipe organ actions, what use is velocity information?

    • #6
      Keying can be done entirely optically without mechanical electrical switches. A slotted optical transmitter/receiver would be under each key and the key itself would have vane that blocked the slot when pressed.
      -Admin

      Allen 965
      Zuma Group Midi Keyboard Encoder
      Zuma Group DM Midi Stop Controller
      Hauptwerk 4.2

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