Antwort: Re: [sdiy] midi optocoupler isolation voltage?

[patchell]

    Here is the one I did...

http://www.silcom.com/~patchell/midictl/midictl.html

    At the bottom of the page I describe the Glockenspiel I converted over to
Midi (it used to be part of a Rogers Organ)...however, I would recomend against
using a 68008...they are no longer availiable (I started this project in 1993
when they were)....an AVR or a PIC would be a perfect processor to use for the
core...

Christian.Bergmiller at daimlerchrysler.com wrote:

> I want to build 64 Outputs to drive solenoids.
> Solid state Relais are too pricey in this quantity
> (and i think they would be not necessary for switching 12V 200mA per Cahnnel)
>
> This thing will be the interface an electromechanical played Instrument (pipe
> organ/chimes)
>
> Christian
>
> >Christian,
> >
> >>Are there any tried and trusted methodes to
> >> limit the voltage difference between the midi devices? (varistors, spark
> >> gaps,neons...?)
> >
> >none that I know of, but given that MIDI is a current loop, and if you check
> >out the schematics you could never have more than 5v on the midi line, spark
> >gaps and such are not really needed..
> >
> >> I just wonder if electrostatic charge could be a problem since some midi
> >> devices are completely ungrounded (battery opperation etc...).
> >
> >From memory the MIDI IN connector SHOULD be grounded, so unless you have a
> >battery powered PC or Atari, you will probably have a ground.
> >
> >> I try to design a midi to relay interface (a bit of "to reinvent the
> >wheel"
> >> ..but i love to invent, so its fun)
> >> I want to build the output stages with N-Channel PowerMosfets driven
> >direcly by
> >> CMOS ICs.
> >
> >why not just use solid state relays?
> >
> >> So far i only plan on the common EMF suppression (?) backward diode
> >parallel to
> >> the output (solenoid/relay...)
> >> any further tips that would increase reliability and/or electrostatic
> >charge
> >> withstand ?
> >
> >Solid state relays, or if you're talking about mains voltages, check out
> >TRIACs..
> >
> >Paul

--
 -Jim
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