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Discussion Starter · #1 ·
I am pretty sure it won't since (i think) servos have to run through a stepper motor, correct? What I am trying to do is make a prop where her head will spin 180 degrees and then stop. I do not want to run this off of the computer though. I want to make this a stand alone prop. This is my idea. I am going to make a "wheeping widdow" and have her crying as people walk up (her back to the people) . Then she will stop crying, head spin 180 to face the people, then use maybe either a sciccor type mechanism or just one that makes her jump at them. When she comes back to the start position, her head will turn back around. Any ideas?
 

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A standard servo will rotate through a range of 90°, but you can order (for a fee of $10) servos that rotate the full 180°. For stand-alone operation, you can use a Scary Terry servo driver board from Cowlacious but you'll want to check with them to make sure the boards can handle the 180° servos. You would run the servo board from a sound source that puts out a single tone for the time you want the motor to rotate, then shut off so that the servo returns to it's home position.
 

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Evil, Wicked, Mean, Nasty
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As Otaku mentions...you can purchase servos that have more range. Depending upon the controller, it can also extend that range.

I'd look at using a picaxe. For $10, it's a mini controller powered by AA batteries. (It'll cost you a bit extra for a serial cable to program it. Or more for a usb cable.)

Picaxe Thread
 

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Evil, Wicked, Mean, Nasty
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I believe efx-tek has a mod to their controllers for use with servos. Check with them.
 

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Years ago I did something similar with an 'open/closed' sign - but using just a geared DC electric motor. The motor would rotate in 'normal polarity' one way until it hit a limit switch which would shut it off. When polarity was reversed, the motor would rotate the opposite way to the second limit switch and shut off.

This was just a relay and two limit switches - switches could be adjusted to give any degree of rotation. You could adjust the speed of the turn with the choice of gear ratio / voltage on the motor. It would probably work anywhere from a slow turn to moderate speed. If you're interested in this approach, let me know and I could probably dig a schematic from the fuzzy memory banks.

If you wanted a really quick 'snap' head turn, you might be able to go with some type of eccentric crank with a solenoid or air cylinder.
 

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Discussion Starter · #6 ·
Thanks for all of your input so far.

Corey, I was originally planning on making a slow turn, but after your input, I am thinking about putting a cylider in there to make it a fast snap. Now all I need to do is think of a way to do that. :googly::undecideton:
 

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The $10 controller post I did a while back will do the servo head turning portion. You will just have to write a simple program to link this controller with the sound/scissor one. I prefer mutliple controllers for things like this - easier to get things right.

Actually almost any controller with a twin relay setup will do this job. I'd suggest the PicoBoo 104 or 105. Ambient sound is the crying and then PIR triggers the cylinder and scissor with no sound or a scream.
 

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you also use a stepper motor to turn the head, precise control but the controller is not as simple as a regular motor or servo. Stepers are used in printers. Just another option if you happen to have access to old printers then you can take the stepper motors out. or you can purchase them. They can have from 4 to 6 wires so the controller needs to have a least four pins to control one.
 

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Years ago I did something similar with an 'open/closed' sign - but using just a geared DC electric motor. The motor would rotate in 'normal polarity' one way until it hit a limit switch which would shut it off. When polarity was reversed, the motor would rotate the opposite way to the second limit switch and shut off.

This was just a relay and two limit switches - switches could be adjusted to give any degree of rotation. You could adjust the speed of the turn with the choice of gear ratio / voltage on the motor. It would probably work anywhere from a slow turn to moderate speed. If you're interested in this approach, let me know and I could probably dig a schematic from the fuzzy memory banks.

If you wanted a really quick 'snap' head turn, you might be able to go with some type of eccentric crank with a solenoid or air cylinder.
This is my suggestion also. On the setup with the head, these switches can be mounted and incorporated with a magnet to activate.http://www.goldmine-elec-products.com/prodinfo.asp?number=G17100. This is activated with a magnet that could be glued to the area, depending on how your prop is made. The magnet will trip the switch and make the continuity of the switch. One can be used for each end of the 180 degree turn. The first turn would stop the head and activate the raising motion setup. When that returns to the down position, the head turns around and the next switch is activated and shuts off. Then resets and waits for the next trigger.

I hope this gives you some help and an idea to work with.
 
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