Homebrew PCBs

--- Stefan Trethan <stefan_trethan@...> wrote:

> Hi,
> 
> 
> has one of you ever tried making a multi-position
> switch directly on the
> PCB like most handheld meters have?
Yes, but not at home with limited tools.... Its great
in volume production as its super cost effective, but
we would take care of the mechanical issues in the
molds.


> I can't gold plate it (yet).
> I think tinning would do for now.
Its a function of life span and environment. Gold is
pretty soft, but at least it doesn't corrode.

> 
> I think of using a M6 screw as axis, just a washer
> on each side to make a  
> bearing
> of a hole in the PCB. Then take a piece of FR4 and
> make the "wiper" with  
> contacts
> of thin sheetmetal.
I think it would be trouble. We always used berylium
copper, and had them formed off site, even for
proto's. I don't think I would want to mess with it at
home. Its nasty stuff.


> The M6 screw would fit into a knob on the front
> panel.
> The "snap" action could be achieved by drilling
> holes in the PCB and  
> letting
> some spring catch them.
FR4 can be pretty abrasive to use as a detent. (we
tired), then again we wanted 20,000 cycles.

> 
> What do you think of that? stupid idea?
Could you use a 360 degree pot, and then detents with
a cam and spring arrangement. It would make the
electrical wear and tear a lot less of a headache.

One could also use optocouplers and a mylar disk...
bit it gets spendy.

I've also seen a magnet, with a sphereical ball
actuator that handled the contact switching as it
rolled along.


> 
> It seems i can't get rotrary switches with enough
> positions.
> Would be nice to be able to just make them how i
> want.
> After all it works in meters...
And other place, a rotary switch is generally not cost
effective, but it is the most intuitive, at least for
those of us in the older generation. The  youngsters
may have grown up with bottom remotes etc, but I still
have a few tv sets with rotary volume and channel
select. EVen Fluke tried to go away from the rotary
switch in the late 80's.... the product failed. They
tried again with a lower priced model in the late
nineties. I don't think its doing to well sales wise.


> 
> tell me what you thik about that.
DIY without extansive cad and proto facilities would
be a challenge, then agan the end result would be
pretty cool. 
Ron
> 
> ST
> 
> 
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