Rate CV was: RE: Joysticks [was: SV: [sdiy] Matrix FX preliminary panel]

[Fredrik Carlqvist]

Use a differentiator! Possibly with a precision fullwave rectifier to get the same result when traveling upward vs downwards.

(A differentiator is an integrator with the capacitor and resistor exchanged) 


Fredrik C


-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl [mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Michael Ruberto
Sent: den 27 oktober 2005 17:31
To: seb at burnit.co.uk; jhaible at debitel.net
Cc: dalenkarl at yahoo.se; synth-diy at dropmix.xs4all.nl
Subject: Rate CV was: RE: Joysticks [was: SV: [sdiy] Matrix FX preliminary panel]


I was thinking it would be neat to have a CV that corresponds to the joystick's rate of travel. The faster you move the joystick the higher the level of the rate CV.

I guess it could be generated with an integrator like a typical lag circuit. 
The wiper from a joystick pot is fed to the lag circuit and a difference amplifier would output the difference between the actual wiper voltage and the lag circuit output. If the joystick is moved rapidly the lag circuit will take time to charge to the new wiper voltage causing a large difference voltage. Would this work?

M. A. Ruberto

>From: Seb Francis <seb at burnit.co.uk>
>To: jhaible at debitel.net
>CC: karl dalen <dalenkarl at yahoo.se>, synth-diy at dropmix.xs4all.nl
>Subject: Joysticks [was: SV: [sdiy] Matrix FX preliminary panel]
>Date: Thu, 27 Oct 2005 10:50:49 +0100
>
>I still have a couple of joysticks available for sale .. I've posted my 
>original email below ..
>
>I'm currently working on a controller device using 2 of these joystick 
>which will output 6 analog CVs as well as fully configurable MIDI data.
>
>Seb
>
>
>jhaible at debitel.net wrote:
>
>>>Where do you get the Joystick, how much for it?
>>>
>>>
>>
>>I don't know yet. Maybe I take that of my Lambda - I never use 
>>pitchbend on a string machine anyway.
>>
>>JH.
>>
>>
>>
>
>
>I have managed to get hold of a small quantity of 3-axis hall effect 
>joysticks at a very good price, with the intention of using them for 
>analog synth control.  They are brand new and I'm selling them at £40 GBP each.
>This is much below the normal retail price of approx £90+VAT.
>
>These kind of joysticks are typically used for industrial control, 
>wheelchairs, etc, so they are really high quality & rugged with a very 
>nice feel.
>
>The particular model I have is the HFX-33S12 which is:
>Model 1300
>3-axis (i.e. joystick moves in X, Y directions, knob twists for Z
>direction)
>Square mounting plate (actual panel cutout needs to be round) Drop in 
>mounting 0.25V to 4.75V output voltage with 2.5V center.
>
>Here is the page and datasheets on the manufacturer's website:
>http://www.chproducts.com/oem/hall_st_1300.html (top picture) 
>http://www.chproducts.com/oem/download/HFX_standard.pdf
>http://www.chproducts.com/oem/download/hfx_stand.pdf
>
>And here is the exact model on the Farnell website:
>http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=206155&N=401
>
>Please contact me off-list if you are interested in these, or have any 
>questions.
>