Help with animation

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hongkongfooey71
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Help with animation

Post by hongkongfooey71 » Mon Jun 21, 2004 6:49 am

Hello,
This will be my first post on this forum. I am looking to animate a pewter miniature. It is a dwarven gyropcopter from Games Workshop. Anyway for anyone not familiar with this model, it is a Fantasy pewter helicopter type machine based in 30mm scale.<p>I want to make the rotors spin 20 to 40 revs per minute and the whole machine move up and down 3 to 6 inches.<p>For the rotor I can drill a hole for a tube to run a miniature motor shaft through. The problem is I am not sure which motor to choose and how to gear it down. Most miniature motors I have seen have an rpm in the 1,000s. <p>Any ideas for the rotor application?<p>For the linear up and down motion, I have done some research in the miniature motors also. I have found a digital linear actuator from danaher controls. The problem with this approach is I will have to buy a stepper motor control. I really wasn't looking to spend more than a few hundred dollars on this project.<p>Any ideas for the up and down motion app?<p>I appreciate any help with this.<p>CJ

shotgunefx
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Re: Help with animation

Post by shotgunefx » Mon Jun 21, 2004 10:28 am

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by hongkongfooey71:
Hello,
This will be my first post on this forum. I am looking to animate a pewter miniature. It is a dwarven gyropcopter from Games Workshop. Anyway for anyone not familiar with this model, it is a Fantasy pewter helicopter type machine based in 30mm scale.<p>I want to make the rotors spin 20 to 40 revs per minute and the whole machine move up and down 3 to 6 inches.<p>For the rotor I can drill a hole for a tube to run a miniature motor shaft through. The problem is I am not sure which motor to choose and how to gear it down. Most miniature motors I have seen have an rpm in the 1,000s. <p>Any ideas for the rotor application?<p>For the linear up and down motion, I have done some research in the miniature motors also. I have found a digital linear actuator from danaher controls. The problem with this approach is I will have to buy a stepper motor control. I really wasn't looking to spend more than a few hundred dollars on this project.<p>Any ideas for the up and down motion app?<p>I appreciate any help with this.<p>CJ
<hr></blockquote><p>Could you use a servo modified to turn 360? They turn slow to begin with.

hongkongfooey71
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Re: Help with animation

Post by hongkongfooey71 » Mon Jun 21, 2004 2:53 pm

Could you use a servo modified to turn 360? They turn slow to begin with. <p>Can you give me some more detail on how to do this? What kind of servo, how to control it etc.etc.<p>Thanks
CJ

shotgunefx
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Re: Help with animation

Post by shotgunefx » Tue Jun 22, 2004 2:45 am

A basic guide to servos can be found here<p>You can also google and find lots of info on them.<p>As far as modifying the servo to rotate continuously, it depends on the servo mfg. So read the above guide.
Decide on a servo.
Google for how to modify the specific servo you plan to buy for continuous rotation before you buy it.

perfectbite
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Re: Help with animation

Post by perfectbite » Tue Jun 22, 2004 10:40 am

Radio control (R/C) has servos that, with some modification, can be made to continuously turn. There is an annual model ship contest here in the SF Bay area on a model sailboat lake. Crowley Marine is a sponsor and model tugboats move model barges through an obstacle course. One of the contestants told me that the model tugboat's propeller shaft's speed and direction came from a directly connected 'heavy duty' R/C modified servo motor. A hobby shop will sell the unmodified servos seperately or with the controller. As Shotgun says, some servo makes do not lend them selves to modification.<p>Is this helicopter in a diorama or just hanging in the air by itself?<p>[ June 22, 2004: Message edited by: perfectbite ]</p>

hongkongfooey71
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Re: Help with animation

Post by hongkongfooey71 » Tue Jun 22, 2004 6:57 pm

Is this helicopter in a diorama or just hanging in the air by itself?<p>It would be mainly for display. Built around a dioramic base, not in the air.<p>CJ

perfectbite
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Re: Help with animation

Post by perfectbite » Tue Jun 22, 2004 9:16 pm

The reason I asked about the staging was to find out if you can conceal/hide the motors and do away with the up/down/rotor shafts. You may be able to hang the rotor motor, using simple loops and knots at the rotor and a hook at the motor, from two sets of hidden or at least camouflaged, widely set apart pulleys set very high and far away from the model and lift the motor up and down thereby lifting the copter. (The motor has be hung from two directions otherwise it will turn too, turning the rotor's fishing line with it) You could 'hang' the copter by two very fine, virtually invisible, nylon fishing lines, very lightly sanding them to take the shine off, One to spin the rotor and one to stop the tail boom from spinning around. If you run the tail boom line at a sharp angle up and away from the model, depending on its length and what it is fixed to, the copter will go nose down as if for a real copter take off (boom down for landing) for the 4 to 6 inches of its movement. Do you plan to have it take off and set back down twice a minute forever?<p>There are folks at this site who, if you asked the right questions, could tell you how to make the copter's rotors speed up and slow down and the chopper itself take off fast or slow. That's beyond my knowing.

hongkongfooey71
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Re: Help with animation

Post by hongkongfooey71 » Wed Jun 23, 2004 4:09 pm

My initial thought was to get a miniature motor, say 8mm diameter. Then I could drill out part of the rotor base and mount it in there or some other mounting option. This would hopefully take care of the rotor action.I haven't quite decided how to get the up and down motion yet. <p>As far as actual range of motion, I was thinking of just having the rotor spin and have a repetitive up and down motion for the vehicle. I.E. it would move up say 6 inches, pause, then move back down to "Land"<p>I have been looking at some of the Nuts and Volts links and have seen some interesting distributors of stepper motor control kits. I may end up doing that, but I am concerned about the size of the motors. The up and down motion motor doesn't have to be super small, as it could be hidden in a decorative base. However the rotor motor has to be small because it has to fit inside the model itself.<p> The model is made from pewter so it is pretty easy to work with.It is usually assembled by gluing the parts together with super glue. I have been thinking of ways to strengthen the bond of the rotors, because it wasn't designed to be animated but as a static model.<p>Anyway I have attached some links to pictures of the model and a parts breakdown, in case anyone was interested in getting a visual.<p>
http://store.us.games-workshop.com/stor ... =16&c=5597<p>http://store.us.games-workshop.com/stor ... code=84-15<p>
Thanks for the tips so far,
CJ

perfectbite
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Re: Help with animation

Post by perfectbite » Wed Jun 23, 2004 8:39 pm

I looked at the visual. It looks like an entirely static model to me and, from the size you said it was, after all a one dwarf helo even full size wouldn't be big so a miniature would be truly miniature and not worth drilling into to put a stepper motor in it. Now a 12 dwarf miniature helo would have some meat to it. <p>If you can get the rotors to turn and lift the rotor post and the copter body with it that would be the way to go. Besides, finding a stepper motor to fit may be impossible. Forget steppers, hanging it by one driven line and 3 support lines, one for the tail section to stop it spinning around. (I didn't see a tail rotor on that model. Those little dwarves could get quite dizzy) and 2 for the hanging servo motor would be easier. Have the rotor motor up high enough so that it isn't in view of the diorama and lift and lower the rotor motor line and stay lines with another servo motor. I would draw it out for you but my scanner's PC is out of service.<p>BTW. I liked Hong Kong, what have you got against it?

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Dave Dixon
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Re: Help with animation

Post by Dave Dixon » Thu Jun 24, 2004 5:51 am

perfectbite,
Hong Kong Phooey <sp?> was a cartoon crime-fighting dog on TV back in the 70's.
All of the Gyrocopters I am aware of have a propeller in the rear to provide forward momentum.
The top rotor spins freely and provides lift. They
must take off and land much like an airplane, and
cannot hover. Take care,
Dave

rshayes
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Re: Help with animation

Post by rshayes » Thu Jun 24, 2004 8:02 am

The smallest motors that I have seen in surplus advertisements are the vibrator motors used in pagers and cell phones. These can be under 1/4 inch diameter by less than 1 inch long, and cost a couple of dollars. The speed is in the 1000 RPM range and adding gearing might be quite a challenge.<p>Portescap (www.portescap.com) and Micro Mo (www.micromo.com) both make lines of gearhead motors. Minimum size is about 1/2 inch in diameter. This would reduce a 1000 RPM motor to the 30-40 RPM range.<p>Driving a stepping motor doesn't have to be complicated. The basic sequences can be generated by a two bit shift register with the output inverted and fed back to the input (also called a Johnson counter or switch-tailed ring counter). This can be a 74HC74, which costs about a quarter. Four darlington transistors will get the current level up high enough to drive the stepping motor coils. Making the counter bidirectional adds a couple of logic gates. Total cost of driving a stepping motor should be less than $10.<p>Chart recorders used to get linear motion using a string wound around a drum driven by a geared down motor. Linear motions of 11 inches or more are easily obtainable. The stepping motor and lead screw from a 5-1/4 inch floppy drive is a possibility, but the range of motion is probably only about 1 to 1-1/2 inches.

hongkongfooey71
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Re: Help with animation

Post by hongkongfooey71 » Mon Jun 28, 2004 7:14 am

Just to update evryone who has responded. It looks like I may end up using the Arrick robotics MD-2 system. This will give me a computerized interface to several stepper motors and allow me to write a program, I.E. something to give me precise motion control.<p>It costs $700.00 though which is more than I wanted to spend. But it may be the simplest option for me.<p>Thanks for the help!!<p>CJ

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Re: Help with animation

Post by Tparker » Mon Jun 28, 2004 9:34 am

Would these suit your needs, I used one of these to turn a radar scanner on a model rc offshore tug boat I built years ago. Pick your gear reduction and then vary speed with voltage. Robbe Minature gearmotors

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Re: Help with animation

Post by Tparker » Mon Jun 28, 2004 9:38 am

My link to the gearmotor page did not work. Go to Robbe home, click on "Drive motors", click on "electric motors", click on "Minature gear boxes"

perfectbite
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Re: Help with animation

Post by perfectbite » Mon Jun 28, 2004 10:26 am

If you decide to use the very fine nylon fishing type line to hang/activate your model, virtually invisible line can be had from specialty Art Supply stores. It is quite expensive, which originally is why I didn't suggest it, but after spending $700 on the components of a control system, plus your time and effort, it would be a let down to use less than the best available.<p>Good Luck.

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