[sdiy] learning from early drum machines?

[David G. Dixon]

Adam,

Fair enough.  I must say I didn't like the look of any of the switches I
found on the web.  I seem to remember many car stereos from my youth with
cooler buttons...

Concerning the flip-flop, yes, it would be there to hold the state, but
wouldn't it also debounce at the same time, or am I mixing metaphors?  Can't
you have one without the other?  (Maybe not; I must confess that I haven't
analyzed it... yet.)

Cheers,
Dave

David G. Dixon
Professor
Department of Materials Engineering
University of British Columbia
309-6350 Stores Road
Vancouver, B.C. V6T 1Z4
Canada
 
Tel 1-604-822-3679
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-----Original Message-----
From: Adam Schabtach [mailto:lists at studionebula.com] 
Sent: Monday, January 12, 2009 1:53 PM
To: 'David G. Dixon'; 'sdiy'
Subject: RE: [sdiy] learning from early drum machines?

Hi David,

I bought a couple of the Mountain Switch tact switches and did not like them
as well as the Omron switches. It was something of an esthetic choice so
maybe other people would like them. The Mountain Switch caps have a colored
insert with a hole in its center, inside a clear cover. The Omron switches
have a solid, translucent white cap so the LED illumination diffuses through
it evenly. The Omrons also seemed to be of slightly higher build quality but
I wouldn't say that the Mountain Switch units were actually shabby.

I decided to not use separate LEDs in my project (a behemoth step sequencer,
which some year will reach a state of completion at which it's worth talking
about) because while you save a little money, you incur greater expense in
the complication of the PCB and the machining of the panel.

I may have come in on the middle of a conversation without really
understanding the topic, but my understanding was that the whole point of
the flip-flop was to hold the state of the step, either on or off. The
original poster specified a "MO" switch, i.e. Momentary On, which means that
the switch itself would not hold the state of the step. I don't think that
push-on/push-off tact switches are common, if they even exist. (Does the
term "tactile" imply a momentary mechanism?)

--Adam 

> -----Original Message-----
> From: David G. Dixon [mailto:dixon at interchange.ubc.ca] 
> Sent: Monday, January 12, 2009 1:35 PM
> To: lists at studionebula.com; 'sdiy'
> Subject: RE: [sdiy] learning from early drum machines?
> 
> Adam,
> 
> Yes, I guess they are a bit pricey (the cheapest I found 
> quickly was $1.39/100 + $0.39/100 for caps, Mountain Switch 
> TS55 series from Mouser).  A less elegant solution is a plain 
> tactile switch (very cheap) with an LED mounted directly above.
> 
> Also, please correct me if I am misguided, but I thought that 
> the whole point of the latch was to provide effective debouncing.
> 
> Dave
>  
> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of 
> Adam Schabtach
> Sent: Monday, January 12, 2009 10:58 AM
> To: 'sdiy'
> Subject: RE: [sdiy] learning from early drum machines?
> 
> 
> > > What about using a pcb-mounted MO tactile switch and a 
> flip-flop?   
> > > With a
> > > backlit LED in the switch, this would be very cool, very 
> intuitive, 
> > > and I think it would also be pretty cheap (depending on 
> the switch).
> > >
> > > Dave
> > 
> > Yeah, that *would* be very cool. All depends on finding some cheap
> > (ish) buttons with LEDs, I suppose. Flipflops aren't a lot.
> > The circuit board to connect it all together might be a pain though.
> 
> The contact bounce of the switches could be really annoying. 
> Basically you'd have a 50/50 chance of the flip-flop ending 
> up in the desired state when you press the button.
> 
> Recently I bought a bunch of Omron illuminated tact switches 
> which would fit the bill. B3W-9 is the series number. Price 
> in small quantities is around US$2.50; whether or not that's 
> "cheap (ish)" depends on your budget. :-)
> 
> Dan: the current popular way to get your feet wet with 
> microcontrollers is the Arduino system. See 
> http://arduino.cc/ . The boards (there are several models 
> from several vendors) are inexpensive and the development 
> software is free. They're very popular with people who want 
> to do interactive stuff with computers but are new to 
> microcontrollers (and programming in general).
> There's lots of example code and discussion. I've never used 
> one but were I starting from scratch with microcontrollers 
> today I'd get an Arduino board.
> 
> --Adam
> 
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