On 9/3/19 1:06 PM, Dennis Lee Bieber wrote:
> On Tue, 3 Sep 2019 07:39:14 -0400, "J.B. Wood" 
> declaimed the following:
>
>> Hello, all.  Just thought I'd revisit this topic since it's been a
>> while.  Has anyone ever constructed a Pi-based standalone 1-2 channel
>> MIDI sequencer?  By standalone I mean it has an integral display and
>> required pushbuttons/rotary knob for device control.
>>
>  What do you intend to show on the display?
>
>  What type of control do you envision? (If you visualize a one/two
> octave keyboard, you then have to specify how many notes in parallel -- one
> note at a time can use a simple row/column keyboard scan -- but when you go
> beyond two notes such a matrix can generate ghost key presses; avoiding
> ghosts requires a linear matrix, which means LOTS of GPIOs -- a 1x24 would
> need 24 GPIOs to detect key presses, while a 4x4 is only using 8 GPIOs for
> 16 keys)
>
Hello, and thanks for your prompt reply.  First, I'm talking about an
elementary MIDI sequencer primarily for live MIDI recording and playback
- not editing (except maybe for punch in/out).  A "keyboard" has no
relevance here as I'm not asking for a synthesizer or MIDI controller.
The display's primary function would be to list/scroll the *.MID files
on the removable storage (flashdrive and/or SD card) and allow selection
of the file(s) to be played via the MIDI "out" port.  The keypad or
pushbuttons on the device would allow for naming of MIDI data collected
at the MIDI "in" port for subsequent storage as a *.MID file on the
removable media.  The front panel controls could also provide for things
like varying the playback tempo or transposing the playback file to
another musical key.  BTW, I wanted this device to interface with a
digital piano so one or two MIDI channels is all I require for recording
and playback.  For the record I have (still in working condition) a 30+
year old Brother (yeah the typewriter company) MDI-30 "Disk Composer"
that provides the functions I've described.  But it has limited internal
memory and only reads/writes to an to a 3.5" floppy disk (using a custom
Brother format).  Sincerely,


--
J. B. Wood             e-mail: arl_123234@hotmail.com

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