Trigger-Type Switch


Thread Starter

Eric Nelson

Hello List,

I'm looking for some sort of "trigger switch" for a project we're
working on. It will be mounted on a moveable arm, and control the speed of a
rotary table. Something like the switch on a hand drill? I think a
thumb-operated (like the H.O. race car controllers you had as a kid) or
twisting-motion (like an electric handtruck) would fit the application
better. I'd prefer to have it variable (potentiometer) rather that only

Hopefully I can find something that's a complete assembly, with the
switch already mounted in a grip. I really don't want to have to "construct"
what I need, since this is probably a commercially available item. I'm just
at a loss as to where to start looking...

Possibly someone on the list knows of a source for this type of


- Eric Nelson
[email protected]
Packaging Associates Automation Inc. [email protected]
Rockaway, NJ, USA

Johan Bengtsson

If I understand you correctly, what you are making is something similar
to what you find in cinemas for handling the film (that is on projectors
where you put the entire film together in one piece before showing it)
That is you want to measure the posistion of a moverable arm using some
kind of potentiometer and use it to control the speed of something that
will increase/decrease the tension of something that is to be winded up
or from this rotary table.

If that is the case I have seen a suitable thing in a electronics supplier
here in sweden ( ). It is probably too far away for
you to buy from, but you may check it out to maybe find some help about
where to get it from a closer distance.
If cost is a really high issue these may not be what you want, they are
not exactly cheap.

It is linear potentiometers (a linear movement) fitted in a house that
looks like a pneumatic cylinder. (several types exist depending on
the desired difference in distance (from 11 mm to 1160mm) and how the
mounting is done)

Johan Bengtsson

P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN
Hi Johan,

Sorry if I misled you by saying that it's mounted on a moveable arm. I
just meant that the switch is not in a "fixed location". What you describe I
would call a "dancer arm". Once I figured out that "twist-grip" was the
appropriate keyword to search with, I've actually found a source for
something that might work at:

This company sells a mountable "throttle pot" which may work, as well as
a plunger-operated potentiometer that may prove to be an even better
solution. Maybe with this reference, the list members will better understand
my application, and can offer other sources for these devices. I'm leaning
towards the "plunger" method, but would prefer to not have to design a
housing for the potentiometer.

Thanks for the link to Elfa though.....Once I learn Swedish I'll explore
their site further! ;o)

- Eric
[email protected]
Packaging Associates Automation Inc. [email protected]
Rockaway, NJ, USA