[sdiy] diy 150 in 1? (using springs for solder free prototyping)

David G. Dixon dixon at interchange.ubc.ca
Thu May 7 20:11:47 CEST 2009


First of all, those spring connectors are actually a royal pain in the ass
to use.  I bought a Radio Shack Electronics Learning Lab 13 months ago (it
seems like a lifetime ago, but that's how this all started for me).  It's
pretty cool, but I graduated from it pretty quickly, and in fact I never
really used it very much; I ended up just reading the book, and then
eventually going straight to Malvino and Horowitz & Hill.  However, I do
remember being fairly unimpressed with the springs.  I would say that
breadboards are a much better option, but you do need a decent layout tool
to make the process bearable (like my little Excel-based creation).
PCB-mounted pots (such as the 16mm Alpha type 41) and switches are also very
convenient for breadboarding.  Also, I had a much better time with all of
this after I went to the local crafts store and bought a pile of little
compartmentalized plastic boxes to keep all my bits in.  I think that if you
get your crap off the floor and into sealable boxes and drawers, it will be
a lot safer for junior.

I've been toying with a slightly different idea (but only toying; i.e.,
daydreaming).  I've noticed that many of the circuit elements we need for
synth modules end up getting used (and, alas, redesigned) over and over.
For example, inverting summers, expo converters, 1-pole LPF stages, OTA VC
gain blocks, etc.  When I design boards now, I realize that getting the
basic circuit design on the board is the easiest part.  It's connecting
these basic circuit building blocks together and routing traces to the
off-board connectors which is the hard (and tiresome) part.

Another thing (warning: long digression here): I've gotten into the habit of
simulating everything I design in Multisim (in fact, if I were to be totally
honest, I'd have to admit that this has become a bit of a crutch for me, and
allows me to be just the tiniest bit lazy about the finer points of design).
Anyhoo, now that I've become a more "advanced" user of Multisim, I have
started to put some of these basic circuit building blocks into
"hierarchical blocks".  These are simply little circuits with named
connectors which are saved to their own Multisim files.  One can bring these
blocks into other circuit simulations, and they appear as rectangles with
named pins.  It's almost like having IC's for everything.  So, for example,
if I want a 1V/octave expo converter in a simulation now, I just call up the
"Expo Converter" hierarchical block, and a rectangle appears with the
following pins: "ExpoCV", "LinCV", "Current1", "Current2", "Current3" and
"Current4".  The "ExpoCV" and "LinCV" pins are summing nodes, and all they
require are input resistors.  The "CurrentX" pins are identical current
sourcing outputs from pnp's in parallel (this expo converter is intended for

So, this hierarchical block business is so fun and easy to use that it has
got me to thinking: why not design real circuits this way?  Of course, that
is exactly what the Dave Smiths of this world do with custom IC's.  That is
not an option for me, but why not design little boards with some common
circuit blocks, and bring all of the connections out to a couple of pin
connectors at the edge; one for the various inputs, and another for power
connections, say.  Then, when this particular block is required, you would
simply stick in the provision for the required female connectors and plug in
the block.

David G. Dixon
Department of Materials Engineering
University of British Columbia
309-6350 Stores Road
Vancouver, B.C. V6T 1Z4
Tel 1-604-822-3679
Fax 1-604-822-3619
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> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> bounces at dropmix.xs4all.nl] On Behalf Of Dan Snazelle
> Sent: Thursday, May 07, 2009 5:24 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] diy 150 in 1? (using springs for solder free prototyping)
> i have been toying with an idea lately but dont know if it would be easy
> to pull off.
> first a little background ((Skip ahead to point A for the idea)
> i am at home with a 4month old baby everyday who lately is NOT letting me
> get a minute of alone time in my shop.
> i cant bring the baby in the shop,  as the floor is covered in toxic
> parts.
> and my wife doesnt want me bringing buckets of loose parts and chips into
> the bedroom with the baby (which is understandable as he could eat them)
> BUT i have a ton of stuff to get done.
> and NO time.
> SO my solution is to make a project system similar to the old 150-in-1
> project kits they sold at radio shack BUT with parts and psu that are
> applicable to Synth DIY...so opamps, OTA's, JFET's, and some lunetta type
> stuff as well as the usual resistor and cap values. oh and i could make a
> little board with pots and jacks too.
> i have a wooden box that would work great for this.
> this would not only be nice to have in the bedroom but in general.
> who wouldnt love a portable design tester??? and ideally,,,it would all be
> socketed. so you could swap out parts when you needed to.
> so...my question is...how the heck to construct such a thing.
> can you buy those springs at a place like mouser? should i rip open an old
> 200 in 1?
> and then there is the PSU issue. getting +/- 12 in a small box...maybe
> dual 9v could work.
> anyway...does anybody else like this idea?
> thanks
> --------------------------------------------
> check out various dan music at:
> http://www.myspace.com/lossnyc
> (updated monthly)
> http://www.soundclick.com/lossnyc.htm
> http://www.indie911.com/dan-snazelle
> (or for techno) http://www.myspace.com/snazelle
> ALSO check out Dan synth/Fx projects:
> www.youtube.com/watch?v=TJRpvaOcUic
> www.youtube.com/watch?v=BqIa_lXQNTA&feature=channel_page
> www.youtube.com/watch?v=V4nJPjGgOcU&feature=channel_page
> and soundtrack/design work:
> NEW: check out Dan's sound design from the 1998 award winning film SAFARI
> by catherine chalmers
> http://www.catherinechalmers.com/videos.cfm
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