keyboard contact rubber fun

[Barry L Klein]

One might be successful with piezo film strips for key sensors.
You should be able to get a voltage proportional to velocity, depression,
and pressure with one sensor along with the right interface circuitry.
The stuff isn't exactly cheap to play with though but maybe the
strips can be really thin?


Barry

----------
From: 	Hairy Harry[SMTP:paia2720 at hotmail.com]
Sent: 	Thursday, August 24, 2000 9:09 AM
To: 	czech at Micronas.Com; dragonser at clara.net
Cc: 	synth-diy at node12b53.a2000.nl
Subject: 	Re: keyboard contact rubber fun

Most keyboards have a scanning matrix... usually bytewide
(8 bits). A clever design would use this to power only those
hall devices that are being scanned at the time... so power
could be a lot lower.

Would this work... depends on the hall device...?

The same would definatly work with led / phototransistor

H^) harry


>From: Martin Czech <czech at Micronas.Com>
>Reply-To: Martin Czech <czech at Micronas.Com>
>To: dragonser at clara.net
>CC: synth-diy at node12b53.a2000.nl
>Subject: Re: keyboard contact rubber fun
>Date: Thu, 24 Aug 2000 17:30:19 +0200 (MET DST)
>
>
>:::Dear Martin
>:::know I know why the contacts sometimes need changing .
>:::I think it would be possible to use reed contacts and magnets to
replace
>:::the rubber contacts ....might it also be possible to use hall effect
>:::devices ?
>
>No, it must be passive, 76 keys gives 76 times the power consumption
>of an otherwise nice hall sensor, much too much for the often
>cheap power supplies.
>
>Yes, velocity means two reeds, one magnet.
>
>m.c.
>

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