I am making a prop for a play and would like a small motor to operate pinocchio's nose in and out. I have colapsible pieces (light saber toy) with medical guide wire attached to move it in and out and would like to attach the wire to a small motor that the actor could wear with a switch for operation in his pocket. I was thinking of using an car antenna motor but it is quite large. Any suggestions? Also, I am a lay person so if you can keep it stupid simple for me that would be great!

 

Just thinking out loud... How about a micro RC motor, which can be modified for continuous rotation.

Here is an article on modifying servos for continuous rotation.

Then, you spool the push wire on a micro drum, and time how long it takes to extend/retract the nose?

The servo motor gear down the motor to a reasonable speed. It could be controlled by an RC Controller or a custom circuit to time the extension/retraction of the nose.

It is also possible to modify the servo so it is controlled simply by DC.

 

Thanks for your quick response! I read about servos but there were so many I no idea which one would work. I assume i buy the micro drum and attach it to the servo? Also, you mentioned an article but nothing was attached. What type of store can I find a servo and micro drum?

 

You'd have to make the "micro drum" yourself. Most servos come with a package of "horns", which includes a circular plate. You could make the drum from this, by attaching at a distance a second circle of plastic.

 

Think I would use a length of all thread, 6-32 or 8-32 as long as extended nose rotated by small gear reduced DC motor. Need something to keep nose from rotating. Would it be possible to have a simple dimentioned cross section drawing of head & nose?
What part of the world are you in?
Found, 6V DC gear reduced motor, 80 rpm, 61 mm long,US $11.50, All Electronics. CAT # DCM-365. Also from ALL, Full Rotation Servo, max RPM 72, CAT # DCS-108, $ 13.95.

 

The nose collapsed is ~3" long and 2" wide. Fully extended it is 10" long and 1/2" wide at the tip. I found a video online of the nose used on Broadway and it refers to a cable system. No Motor! I have no idea how they did the cable but if I could figure it out I think I would have an easy solution.

skip to 3:34 of this video you can see the Broadway nose

https://www.facebook.com/MahaliaNOLA/videos/581683809070/

I am in Utah

Thanks!

 

The actor is wearing the nose, nose made up of conic sections just like a collapsable antenna? Cable something like a weed-eater string within a flexable tube. I see the before mentioned continuous rotation servo with a 2.6" dia reel constrained to enable push as well as pull. Servo control positioning via linear pot. A single 555 would do for servo control.
Servos available from hobby shops, on line or All Electronics.

 

Another option might be a pneumatic system, something like a coiled-up party blower.

 

Do you still need a nose or is light saber parts suitable? What is length of cable from in to out? About 7 or 8 in.?
A single turn drum would allow limit switches as I believe continuous rotation servos only allow direction & speed.
I'm about to say something stupid but as I have above mentioned servo, .117" plastic, .095 weed eater string & some IC's, would you like for me to make the system?

 

After viewing the video, I can see this done with zero electronics. Heresy on an electronics site, I know. But staying in the spirit of AAC and Bernard's great ideas, a standard high torque servo motor with a 2.25" radius semicircular horn might work. That would give you 7" of extension (from 3" to 10"). The operating cable would be in a tubing sheath and run up the actors nose bridge (hidden with a small bit of nose putty) and over his head (hidden by a wig. Then down his back to a power unit in a special pocket in the back of his costume coat. Two or three wires would run from there to a knob or slider (potentiometer) in a side pocket or a glove. Wish I was home or I'd sketch up the idea.

The thing here is you don't have to mount the motor near the actors face/head. A larger motor could be used, but then powering it becomes a constraint.

Can you use any of this, Bernard/TS?

 

Thanks, djsfantasi, now I do not have to say it. The standard servo has the advantage of position control, eleminating limit switches. I also have a std. servo. Found a short , 1.3 in travel , linear action pot at Electronic Goldmine.
In video motor is not shown but is controlled by " a switch".

 

Wow! These all sound like great ideas but as I mentioned I am a lay person so most of it is greek to me!!! I have been all over town today stopping at auto parts, home supply and an airplane/remote car hobbyist store. The hobbyist store proved most fruitful but I am still stuck. He gave me a small servo (180 degree) some wires with sleeves that are bendable yet strong enough to push the nose out. However, he thought the lever with some kind of pulley might be easier than trying to attach a spool and get the timing right.

I also picked up a choke cable from a auto store to add to my pile of parts. I have not been able to find any information on how I might make a pulley lever like the one in the video. I will gather up what I have and post some pics.

 

OK...as promised here are some pics...the nose is just a quick version.

 

What is the oz in rating of your servo? Mine is 49 oz in @ 6 V & when attached to 2.25 rad. drum leaves 21 oz of push-pull. This seems enough when using .091 in wead eater line in 36 in of .25 in od polyethylene tubing.

 

The only thing I can see on the servo is AS-100. It was just given to me so I don't have the box or anything.
I am going to dig out the weed eater line and see what i can do with that. Where can I find a spool to attach to the servo? I assume to attach a spool I just remove the little plastic fly wheel and attach it there?


I had someone tell me to use a Micro linear actuator and a potentiometer used in robotics but of course I would have no clue how to use or even where to get them!

 

The weed eater line should be stiff enough to push out the nose. I made a quick freehand sketch to show my thoughts on a drum solution.
A standard servo is 39.4 mm X 18.5 mm X 37.1 mm, does this fit yours?

 

I'd remove the little plastic flywheel, and screw it onto one end of the spool drum. Make sure the center hole of the screw lines up with the center hole of the flywheel, so you can screw it back on.

Nevermind - @Bernard has a great diagram. Although I'd still use the servo little plastic flywheel as an attachment point. By the way, "little plastic flywheel" is also known as a servo horn.

Picture of servo horns (not the screws!!)

 

Add with Edit disappeared. A small linear actuator might be made with all thread, gear motor, some small parts along with weed eater string and tubing. Drum then not needed.

 

I'm actually working to do the same thing. I have a standard servo and winch servo and have the basic nose mech done. It pushes easily with 1/32" and 1/16" galvanized wire rope but I can't get it to loop around a wheel or get the servo to push the distance.

I can't seem to post my video here but it is on my Instagram under dougblemker.

https://instagram.com/p/30LI5vt_pk/

Any thoughts are appreciated.

 

Rather than a winch and cable, a 'lazy tongs' mechanism might be easier to construct.