[sdiy] OT: OrCad

[Tim Parkhurst]

> -----Original Message-----
> From: Bert Schiettecatte [mailto:bert.schiettecatte at esat.kuleuven.ac.be]
> Sent: Thursday, April 03, 2003 2:34 AM
> To: j vallier
> Cc: synth-diy at dropmix.xs4all.nl
> Subject: RE: [sdiy] OT: OrCad
> 
> Now that we're on the topic: how are the electrical / mechanical
> components
> of
> a synth designed before it goes into prototyping or production?
> 
*****************************************************
Hi Bert, 

Don't know if you got any off-list responses to your question, but as a
mechanical drafter / designer I thought I'd give it a shot. Basically, I
feel that products should be designed "Top Down." In other words, you start
with a fairly well polished idea/drawing/specification for the finished
product, THEN you work back down through the design elements in roughly this
order:
case-housing-power supply 
panel & interface components 
PCB mounting-dimensions
PCB layout

Most of these tasks can be carried out concurrently, but they will generally
affect each other in the order listed (i.e., a change or problem in one area
will affect the items below it). Of course, there are exceptions to every
rule, but this is generally the approach I've seen in the industry. 

Keeping this 'design sequence' in mind, if you're designing a synth you
should first create a drawing and list of specs. The first drawing can be
just a rough version (quick pencil sketches that will allow you to create
and refine concepts), but you will want to create a detailed assembly/layout
drawing before you get too far. Using CAD, I will typically create a 3D
model or a series or 2D views that will show the 'envelope' or outline of
the case and all the mechanical components (switches, pots, displays,
hardware, etc.) Remember that you don't need to create a detailed model or
drawing of every component, but you will need to accurately represent all
outer surfaces that mount, mate, or can interfere with other parts. These
envelopes can be as simple as a rectangular box with a couple of circles for
mounting holes to represent something like a panel mount switch. Again, you
start with what you want from the finished product and work back to define
the necessary details.

Contact me off list if you want more info.

Happy Hacking!

Tim Servo
"Nothing says 'I love you' like a cold six pack!" - Albert Einstein
(probably)



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