Having some fun with servos (never used them, so it's extra nice 🤓 ). Want to arrange them to trigger a spray can. That'll be the hard part.


First attempt with servos and spray bottle. Seems motors too weak, or construction too bad? Any ideas?


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@sciss It looks like they are only rotating 90° and I think you need to compress the pump a bit more. Can you make them rotate a full 180°?

You can also try to use a circular armature with the line wrapped around the outside – this will translate the entire rotation to linear.

@praxeology yes, they do rotate 180° (when they are not attached to any force); I'm trying an angle of up to 150° in the example, but the horn doesn't drag much further than 60° or so.

@praxeology any links to 'circular armature' - I have no idea what that would be?

@sciss Basically like an oreo cookie (Prinzenrolle?); A wheel with a groove in it. It will make all the motion translate to linear. Right now much of the motion of your arm is orthogonal to the pump axis and does not move the handle. So most of the work has to be done in the last few degrees of the sweep and this puts more stress on the motor.

But I suspect you might need a servo with more torque.

@praxeology @sciss
A student in my class on rapid prototyping last year used a pencil to make a longer lever: movie is only on insta, sorry for that instagram.com/p/CAr7JOQohlN/

@fblchrstn @praxeology good point. I have ordered a few stronger motors now, but definitely the trigger could be slightly extended, I don't think it yet uses the full travel distance that a 180° rotation would amount to.

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