Re: [sdiy] velocity sensing problems?

[Roman]

	if the keys that don't respond to velocity, play with maximum velocity data, it sure is first contact that is not conducting. 

	Velocity keyboard usually has 2 contacts per key, and 2 conductive rubber "jumpers". They are shaped as they are on different heights. When key is pressed, first rubber touches contact. When key is pressed deeper, the second one closes. Keyboard measures time between those two events, hence speed or velocity of key-pressing. 

	A note is played when second contact is closed. By that time keyboard has measured the velocity and knows what velocity data to send. If there was no first event, but the only what happens is second contact closing, keyboard assumes there was no delay between those 2, and plays with highest velocity. 
	That was long description of really simple thing. 

	Basically you need to check if all contacts are not broken, and if the conductive rubber is really conductive on those keys. 
	Roman
---- Wiadomość Oryginalna ----
Od: Ordeish at aol.com
Do: synth-diy at dropmix.xs4all.nl
Data: Thu, 19 Feb 2004 08:36:56 EST
Temat: [sdiy] velocity sensing problems?

   Hi there all. I am preparing my Kurzweill K1000 for sale, but have found that some of the keys are not sensing velocity. Does anyone know much about velocity sensitive keyboards, enough to give me an idea of what I am looking for as a problem? Ive been checking the diodes, and all seem to be ok. There is some oxidation on some of the leads that *looked* like they were bridging, but cleaning it up does not seem to make much of a change.   any help is greatly appreciated!   Thankyou, Edward

 
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