# 3 axis with wiper motors?



## CrazedHaunter (Nov 18, 2012)

I have been toying with an idea not sure if it can be done or if I want to attempt it but I have a large werewolf mask and arms that I want to make a prop out of. My idea is to make it a 3 axis head, but I am thinking it will be to heavy for normal servos so I was thinking wiper motors. I know there is a tut. On using wiper motors as servos. Has anyone attempted this? Am I nuts to even try? Can a regular prop controller like Halstaff's random controller work. Or will it burn out?


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## HomeyDaClown (Oct 3, 2009)

CrazedHaunter said:


> I have been toying with an idea not sure if it can be done or if I want to attempt it but I have a large werewolf mask and arms that I want to make a prop out of. My idea is to make it a 3 axis head, but I am thinking it will be to heavy for normal servos so I was thinking wiper motors. I know there is a tut. On using wiper motors as servos. Has anyone attempted this? Am I nuts to even try? Can a regular prop controller like Halstaff's random controller work. Or will it burn out?


If you can successfully convert a wiper motor into a servo (monster servo), the application is no different than using regular servos since they both are driven with a servo signal (PPM). Only with a wiper motor you will need a bit more hefty power supply.

If your mask is large enough to house three wiper motors, it must be pretty big. Otherwise you'd have to use pulleys and a cable sytem so the wiper motors could be moounted externally. If it were me, I'd look into using small pnumatic cylinders instead.


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## halstaff (Nov 18, 2009)

Have you looked at some of the heavy duty servos? The standard servo many of us use for our 3 axis skulls is the Hitec 425BB which has 57oz./in of torque at 6V. I've used the 485HB which has 83.3oz./in and the 645MG which has 133oz./in at 6V.
Here's a comparison chart of different Hitec servos - http://www.servocity.com/html/hitec_servos.html


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## bfjou812 (Aug 15, 2008)

Try this
http://www.hauntforum.com/showthread.php?t=12435&highlight=monster+servo


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## CrazedHaunter (Nov 18, 2012)

HomeyDaClown,Halstaff andBfjou812, thank you all for your input. Homey the mask is big enough to fit 3 wiper motors barely. And I am not really looking to step into pneumatics yet.
Bf reading through that link makes me lean more towards doing it Halstaff's way. Halstaff thanks for that link. Now I just have to figure just how big a servo I will need. I guess I need to foam the mask and weigh it then figure out how much torque it requires, I'd hate to buy $150/170 servos when I $70 ones will serve. My plan now is to wait till I build the prop and make the head so I can convert it to 3 axis later. Thanks again I really appreciate the input


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## corey872 (Jan 10, 2010)

Weight/inertia will be one factor - try to choose materials to minimize this - lightweight foam, thin plastic, fiberglass, etc. Balance will also be a big factor. You might be able to get away with surprisingly small servos if the head can be balanced very well. You say werewolf, so that implies somewhat of a big snout on the front. You might have to put a few chunks of iron or lead in the back of the head to counterbalance that. But if the balance is good and the central pivot bearing is smooth and low friction, a very light touch could move it in any direction.


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## HomeyDaClown (Oct 3, 2009)

My Twisty 3-axis mechanism (covered in a older thread here and in a tutorial over at GOE) lends well to this type of application, you will just have to use a larger spring in the neck to balance the extra weight. The spring takes the load off the nod and tilt motors, the rotate motor only gets a little backlash when it stops rotating. Although I think wiper motors will not strain much here.

There was also an older thread by Dr. Morbius on a simple wiper motor to servo conversion that should be easy to find.


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## CrazedHaunter (Nov 18, 2012)

Wow Homey I like the movement on your twisty.. I'm going to have to try that. My plan for now is to stiffen the mask by using Alan Hopps method of masking tape and gorilla glue. Although I only use two or three applications of glue instead of filling it all the way up. This keeps it hollow and lite but stiff enough to use. I've used this before on 2 masks with great success but they are smaller. Once I have this done I will weigh it and compare it to a lindberg, hopefully it will not be much heavier and I can use standard servos. I don't plan on starting this till next year just formulating plans and ideas right now.


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