Servo linkage for back and forth motion

Other Hardware Motors, Mechanics, Power and CNC
1

I'm just starting out with my Arduino, and I got one of the basic starter kits with a servo and some standard horns. I can control the servo and have it rotate from 0 to 180 degrees. What I'm looking for is a linkage that translates the servo's rotation into pure back and forth motion. What I want to do is have the servo press a button, without having to mount the servo next to the button.

I've played with a piece of wood with a hole cut in it, and a dowel rod that goes in the hole which is attached to a servo horn, to get the back and forth motion. I suspect there is a standard name for such a part, but I don't know what it is.

When I see servo controls for sale at ebay sites, I don't have the background yet to know what control I would want, and I can't visualize how a particular piece translates the rotational aspect of the servo into other motion.

So, is there a standard name for the linkage that allows a servo to do pure back and forth motion?

Ultimately for my project, I might like something that looks like a finger that is controlled by the servo to press the button. There is the Roy kickstarter project (http://www.kickstarter.com/projects/1647660643/meet-roy-an-experiment-in-animatronics-part-one?ref=category), that if successfully funded would offer a laser cut kit to make a finger. Are there other sources of something like a robot finger for pressing buttons at US $50 or cheaper?

2

You can have a pin on the horn that sits in a slot on the linear moving part.

Or have the horn move a link with pivot points at both ends that in turn moves the linear part.

Yes I'm sure there are proper names for these parts, but I'm an EE not an ME :slight_smile:

Rob

3

MichaelMeissner:
I've played with a piece of wood with a hole cut in it, and a dowel rod that goes in the hole which is attached to a servo horn, to get the back and forth motion. I suspect there is a standard name for such a part, but I don't know what it is.

Crank and slider.

KMODDL will stick you at your computer for a few days.

4

MichaelMeissner:
So, is there a standard name for the linkage that allows a servo to do pure back and forth motion?

You might also want to look here (you might be able to find similar parts on Ebay for cheaper):

http://servocity.com/html/linkages.html

Also - there do exist servos with linear motion (that is, small linear-motion servos - not linear actuators with servo controllers, though if you need those, they exist too).

5

KMODDLL FTW

6

cr0sh:
You might also want to look here (you might be able to find similar parts on Ebay for cheaper):

http://servocity.com/html/linkages.html

I've seen servocity.com before as well as other places (robotshot.com, diydrones.com etc.), but never having done anything with servos before, I don't know exactly what parts I need to make a servo move up and down, enough to push a camera shutter button at the 1/2 and full positions (call it 1/4" or 6mm, but I probably need to fine tune it more or less). Unfortunately, I didn't see any FAQs there. That location just lists the various parts, assuming you know what you need.

If I can source it from a US distributor, it may only be a week to find out if I ordered the wrong part, but if I need to source it from an Asian distributor, it can be a longer lead time to wait for parts, or pay more in shipping than the part is worth. It can be frustrating if you have something you want to build, and are sitting waiting for delivery. :expressionless:

cr0sh:
Also - there do exist servos with linear motion (that is, small linear-motion servos - not linear actuators with servo controllers, though if you need those, they exist too).

Ok, I'll be on the lookout for them.

Chagrin:
Crank and slider.

Thanks. It should make it somewhat simpler to look for, but I'm still having trouble visualizing the whole assembly.

Chagrin:
KMODDL will stick you at your computer for a few days.

Eventually perhaps. At the moment, I am interested in very simple movements, but I've bookmarked it for later study. Thanks.

7

I think what you are looking for is a Clevis, like this one:

You put i over the servo arm:

and secure it with a screw. In the other end you glue a rod, that will then move back and forth.

You coul also use a Linkage Stopper

the threaded end goes in the servo arm, and the rod goes throu the hole, and gets secured by the screw

8

The simple servo application is to use a crankshaft setup with the servo rotating between 0 and 180 deg to move an object back and fourth.

9

Erni:
I think what you are looking for is a Clevis,

Thanks, that looks looks like what I want.

zoomkat:
The simple servo application is to use a crankshaft setup with the servo rotating between 0 and 180 deg to move an object back and fourth.

Yep. I knew the general idea, but what I was blocked on was the name of the parts to order. Thanks.