[sdiy] Keyboard scanner

[paul.maddox.mail-list at synth.net]

<cough>

Why reinvent the wheel?

http://www.midi-hardware.com/products.html

Roman Sowa has already done a superb collection of keyscan -> Midi  
modules, and you can bolt on ADC modules and all sorts of usefull stuff.


But to be honest, goto ebay, pick up a cheap jap/tai midi controller  
for $50, rip the case off, and you're done...

Paul


>
> I'd be interested in this for my polysynth as I've yet to design one  
>  for it.  I like AVRs and for 8bit micros I'm a big fan of them.   
> I'd  much rather a system that outputs midi format data over uart   
> though.. I assume this might be more useful for others too.
>   The diode matrix arrangement could be made compatible with FATAR   
> keybeds like the ones from doepffer, and I would also very much like  
>  the keboard scanner to have inputs for pitch/mod wheels and also   
> sustain and control pedals...  I guess this isn't quite what you had  
>  planned and it amounts to a complete keyboard controller interface,  
>  but it would be a great circuit.. the ones doepffer do aren't quite  
>  complete.
>   The user could interface via MIDI or just direct UART, or you   
> could even add SPI.. having the MIDI standard protocol already in   
> place makes it easy for others to use, and it's all there to be used  
>  or ignored.  Thanks George
>
> --- On Tue, 28/7/09, Neil Johnson <neil.johnson97 at ntlworld.com> wrote:
>
>> From: Neil Johnson <neil.johnson97 at ntlworld.com>
>> Subject: [sdiy] Keyboard scanner
>> To: "synth diy" <synth-diy at dropmix.xs4all.nl>
>> Date: Tuesday, 28 July, 2009, 8:58 PM
>> Hi all,
>>
>> As part of my Siel Opera 6 project I am designing a 61-key
>> keyboard scanner module, based on an Atmel ATmega8.  It
>> scans all 61 keys via an external 74LS154 decoder and diode
>> matrix (already present on the existing contacts board),
>> measures the time-of-flight, and works out note-on velocity
>> and note-off velocity.  It also handles pitch-bend
>> wheel, modulation wheel, expression pedal and sustain pedal
>> analogue inputs.  The intention is that it will talk to
>> a master processor via SPI (100kbps should be fast enough).
>>
>> If this board were to be used for other projects it would
>> be useful if the 74LS154 was also on the scanner PCB,
>> together with a suitably larger connector (probably 26-pin
>> IDC header).  This would necessitate a larger board
>> than a dedicated one for my project.
>>
>> I figure this project might also be useful to others,
>> perhaps those building their own keyboards.  How much
>> interest would there be?  If you would find such a
>> board useful then please email me off-list and if there is
>> enough interest I'll extend the design accordingly.
>>
>> Cheers,
>> Neil
>> --
>> http://www.njohnson.co.uk
>>
>>
>>
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>
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