21 Aug
2009
21 Aug
'09
8:12 p.m.
On Thu, 20 Aug 2009 17:21:10 -0700
Ken Restivo <ken(a)restivo.org> wrote:
On Fri, Aug 14, 2009 at 10:19:25PM +0100, Folderol
wrote:
Hmmm. The best 'introductory' reading is probably on the arduino forums!
Basically, any half decent encoder has at least three outputs. A, B &
Z or N
A and B are the running pulses and are timed such that as well as
giving you a count, they can also tell you the direction. N or Z is the
index and occurs exactly once per revolution of the encoder.
So, as an example if you have a 500 pulse encoder and fix it to a
pedal so you have 180deg of movement you'll actually get a useful 250
pulses. Position the encoder shaft so that the index comes at 90deg and
you'll be able to count +/- 125 pulses and seeing as MIDI only gives
you 127 for most operations that's nearly twice what you need.
Hmmm again. I'm used to just handling these and not having to buy
them. Just looked up on RS and the cheapest one that fits the bill is
about 40 squids :(
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduc…
--
Will J Godfrey
http://www.musically.me.uk
On Fri, 14 Aug 2009 22:43:15 +0200
Arnold Krille <arnold(a)arnoldarts.de> wrote:
This sounds intriguing. Right now I have an Arduino, and the reason I haven't used it
is because I tried hooking it up to a volume pedal and the noise was so intense it was
spewing out MIDI messages constantly... unusable. I had considered rigging up a passive
analog LPF, or maybe doing some smoothing in software on the Arduino, but ran out of
time/patience.
What would be involved in fitting this kind of encoder to a volume pedal? I can find
guitar-style volume pedals easily, and they're cheap. The advantage is that I could
use a very cheap ATTiny2313 with no ADC instead of an ATMega Arduino. Encoders sound like
the way to go.
On Friday 14 August 2009 21:59:53 Ken Restivo
wrote:
Nonono
Building an Arduino footpedal will be much more fun :)
Hmmm.
Instead of a pot on one of the analog inputs use a cheap shaft encoder
and count pulses.
It sounds great. Now I'm either going to hack
together an auto-wah via AMS
or something and an envelope follower, or build myself an Arduino pedal
footcontroller.
Get a footcontroller or control it from the keyboards modulation-wheel (if not
used otherwise). Auto-Wah sounds crap.
Arnold Double Hmmm
Fix it so that the index pulse is at exactly the halfway point in the
travel, and it will 'silently' re-calibrate itself every time you pass
throgh that point.
I don't know what an "index pulse" is. If you could point me to some good
introductory reading material on dealing with encoders, I'd find it very interesting
indeed.
Thanks.
-ken