Servo arm to mount another servo?

[Dan Linder]

I'm trying to make a basic two-servo pan/tilt setup.  I know with enough zip-ties and foam tape I could get one servo attached to the other in the T-formation, but that really seems overly hack-ish.

(For what it's worth, these are two of the Radio Shack supplied Parallax servos - http://www.radioshack.com/product/index.jsp?productId=12296088).

I think I'd really like one that would replace one arm of a servo with a U-shaped bracket, but if there is another option I'm missing I'm all ears.

For what it's worth, I'm looking at mounting a small battery powered squirt gun for use in my basement  (the "Cat Scram" device mentioned back in June).   Hopefully we'll only need this for only a short period of time.   (I don't really want a garden hose with expensive industrial servos and a fast acting electronic water valve...)

Any ideas?

Dan

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[Kevin Fusselman]

Brandon /Dave had a nice setup for the MMM camera that might be adapted...

Guys?

[David Knaack]

Its designed for a smaller servo size, you'd probably have to modify it a bit.

I'd be inclined to mount the first servo on a fixed mount, then attach a board to the control horn, and use that to mount the other servo. It's about as compact as you can get, and the plate that connects the two servos would be a nice 3D printer project.

[Dan Linder]

That's about what I've come up with in my mind.  Now to get time in my garage tonight to work on it a bit.

Out of curiosity, is the "stub" on the servo that the arms connect to any sort of standard or is it all based on the servo manufacturer and/or size?  I know that some RC hobby stores sell packs of arms (the round disk-arm would be perfect) and would be a bit lighter for my purposes.

If I come up with anything substantially different I'll send a photo/description.

Thanks,

Dan

[Ben Hutcheson]

The splined shaft on the servo is not a standard size, unfortunately.  If you're buying name brand servos, they'll be one of several standard-ish sizes.  If they're off-brand Chinese servos, then they're very possibly manufacturer-specific and not used for anything else.

If you're planning to make something on the 3D printer, though, it shouldn't matter.  It's not like the printer has enough resolution to mate with the splines, anyway.  So you just have to print a blind hole of roughly appropriate size, heat it up, and press it in place.  That should hold things pretty securely.