Conference napalm::commusic_v1

    
    
    
    You could do this a lot easier with x-10 stuff.  Check out the x-10
    conference.  Sorry, can't remember the node off hand...
    
    \John
    

    I know about X-10 stuff, and I thought it was kind of overkill.
    I don't need to switch 300 watts, just momentarily ground something
    less than a milliwatt for a second.
    
    The X-10 switches, besides being mechanically very noisy ("whack!", not
    really appropriate for studio use), are rather big and bulky.

    Ah, I didn't know about relay-closure modules.
    
    The only trouble is for my application I would have to use a whole
    bunch of house codes.  While the only installation of this would be
    in an industrial building, I would prefer not to leave the studio
    open to unauthorized "remote control" over the power lines.
    
    Especially considering what is already on those power lines.  (Like
    the clocks in ZKO get sync signals over the power, and there are
    other things that are not so compatible with X-10 signals.)
    
    MIDI has lots more address space.  I visualize a one-unit rack module
    with screw terminals on the back for hooking up to a rack's worth
    of cassette machines (say 8) with two or three controls per machine
    (STOP, PLAY, and REWIND).   Set thumbwheel on the box to set the
    MIDI channel it listens to, then use controller on/off messages to
    control the relays.
    
    I could have up to 16 racks of 8 machines each, on a single control
    cable.  This is more than I can see needing.
    
    The application, by the way, is a computer controlled scheduled
    playback of recorded material at certain times of the day, so you
    don't have to have a guy show up every 30 minutes to play the next
    tape.

	Sometime last year, Electronic Musician had a kit/do it your self
	article for this sort of thing. It had 8 switched outputs that
	were tied to midi note #, and the midi channel was selectable.
	Someone had a PC card and would program the EPROMs for you. I thought
	about this for a lighting controller, but ran out of midi channels
	in my rack set up (yes, all 16 are allocated for something).

							Jens

    
    
    Does the sound have to go to a lot of different places, too?  If so,
    the separate machine approach facilitates this routing requirement.
    
    If not, you could use one of the PC voice mail cards to store the sound
    data, and write a little bit of code to access and playback these files
    according to your schedule.  Disk space requirements are proportional
    to your need for fidelity.  The card I have (Bigmouth) uses about 3k
    per second for reasonable quality speech.  If you want to check it out,
    call (714) 499-5454.
    
    So what's this thing going to be used for, really?
    

    Nothing nearly so sophisticated, but I'm interested in some of the same
    technology. What I'd like to do is simply be able to turn on a light
    from a MIDI command. What I have in mind is that I have a lot of
    sequences that repeat some chorus over and over at the end, and my
    singer and I can never remember exactly how many times to repeat. It
    would be great if I could put a small light on our monitor speaker that
    would go on at the start of the last refrain. Isn't there anything off
    the shelf that could be used for something like this?
    
    - Ram

Hi !

I think DOEPFER Electronics has something like that, but I don't know about the
distribution channels inthe States (if at all). But I can find out if you want.
Just let me know.

	Richard

This would be trivial to program up on an Atari STe, with a very small
ammount of external hardware (buffers and relays).

You could use any random ST with 8 bits on the printer port, or you
could use the STe with the enhanced "joystick" ports, and use the
bidirectional port bits provided there to drive another 16 or so.

Of course, then you could program the entire application on the ST as
well, and get rid of whatever it is that wakes up every 30 minutes to do
something.   Of course, then you wouldn't need the Midi port, and could
just use a clone...

    The "buffers and relays" are probably the most expensive part of
    building one of these things.  8 bits is probably not enough for
    how big this might grow, but is enough to start.
    
    The application is an automated radio station.  Professional
    broadcast equipment that can do this (used by those FM stations
    with no DJs and all pre-programmed music) is quite expensive,
    and the kind of equipment that can be controlled this way is
    typically not cassette players.  The controllers are not very
    flexible, either.  I need to be able to step to the next selection
    based on running time of the previous selection, as not all tapes
    will have the sub-sonic tone burst that the pro machines key on.
    
    But for this application, most of the prerecorded stuff will be
    in cassette format, not open reel or cartridge.
    
    I was thinking of a simple UART receiving 8 bits, the UART's internal
    latch driving the buffers and thence the relays.  That would be the
    cheapest way to drive 8 switches.  A way to extend it is to send
    pairs of bytes, with the extra bits being an address to match against
    DIP switches.
    
    But a comparator here, a few 8-bit latches there, and pretty soon
    it is cheaper to use one of those CPU+RAM+UART chips and do the
    decoding in software.
    
    Designs which require a particular type of controlling computer
    are not a good idea, so it should be a serial interface.
    
    Off-the-shelf designs are preferred of course.