Thread: Oscillating head movement

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Hi guys,

I am in the mids of building a grave digger / care taker that I want to make the head move back and forth.

I have read tons of message threads about how to "animate a prop" many of which are incredibly expensive using servos and complex prop controlling / activation boards, etc. The problem is that I don't need anything that complex ... I just want to make his head turn maybe 120 degrees back and forth slowly.

I was thinking about using a simple fan oscillation motor to do it ... but I wanted to know if either A.) someone has been able to do it ... or B.) is there a better (cost effective) way.

Like I said - I only want his head to move slowly back and forth slowly (panning), no tilting or spinning around in circles ... simple. Just enough movement to add something to a normally static prop.

Can anyone point me in the right direction to do this?

Thank you in advance ...

HiRez00

Fan motors can do this, but tend to overheat and fail. The fan's blades are part of the cooling system for the motor. You'll have better results using a reindeer motor, which are available at a couple of surplus outlets for a few bucks. There's several threads here about how to set up the linkage to make a head turn back and forth. Try a search for "reindeer motors" and "stirring witch".

A simple setup like this would work fine:

Crank

Originally Posted by DaveintheGrave

A simple setup like this would work fine:

Crank

how could you use that to spin a head from side to side?

I think dave was thinking of of another side-to-side movment. You are thinking more of a turning movement.

My bad ... Maybe I didn't explain it poperly. I want the head to do a sort of turning side to side movement similar to someone shaking their head as if to say "no".

this i think this will work . to do it u would have to put a stoper then it goes the other way one more stoper on the other side.

-BYH

good sugestions out there.

The gearmotor will work. The reference to a stopper needs to be clarified.

To use a gearmotor you will need to reverse polarity, provided it is a DC motor. This is based on the idea of mounting to prop directly to the output shaft. Now this is not as easy as it sounds. What you would need is a spring loaded toggle switch. You would mount this switch in the middle of the turn. On the prop you would mount two arms. One at each end of the turn. As the head turns the arm on one side will approach the switch and then move the switch arm towards its middle point. Once the switch reaches the high point in the middle, its sping load will flip the switch arm to the other side. This will provide reverse polarity to the motor and the head will begin to turn in the opposite direction.

You will wire the motor with 4 wires.

The other option is to use the mechanical approach. The one shown earlier in this thread will work fine. You mount this mechanical unit horizontally. Mount the head on the axis of the pivot point for the arm. This will result in the rotation from side to side you are looking for. Of course the total degree of movement will be limited to less than 90 degrees.

You can use a wiper motor with a speed controller also.