# Shaking MR thrifty



## krough (Oct 7, 2004)

I am going to build the Shaking MR thrifty prop. I am curious as to how powerful the motor need to be to shake the cage? 

Krough


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## Zombie-F (Apr 12, 2004)

It doesn't need to be very powerful at all as the motor itself doesn't shake the cage. The motor is mounted on top of the cage and it spins a weight (not very heavy, I'd say mine was less than 1 lb). The motion of the weight rotating is what causes the cage to spin. This is the same mechanism that makes a beeper vibrate, only on a larger scale.

There's not much info on the motor I'm using since I got it for free from a junk box of motors that is kept at work. I can tell you it's a 12VDC motor, and it spins pretty fast. You'll need to build the circuit I have detailed in my directions to be able to adjust the voltage to the motor, and thus adjust its speed of rotation.


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## krough (Oct 7, 2004)

I have an AC motor that spins at about 120 RPM, Sounds like that might not be fast enough. hmmm


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## Zombie-F (Apr 12, 2004)

Oh geez, that's probably either perfect, or just more than fast enough! In fact, I'd say that'll work perfectly, and you could easily use an AC light dimmer to control the speed.


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## krough (Oct 7, 2004)

Great, I am starting the build tonight.

Thanks for the quick responses.
I am also building the MITB according to your plans

Krough


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## Zombie-F (Apr 12, 2004)

Cool! Thanks for the interest in my projects! For an alternate take on the MiTB, check out another person's version (based off of my design). This is from Spooky Lake:

http://www.spookylake.com/MIB.htm

Basically, he had a high-speed AC motor and used pulleys and belts to drive down the rotation speed while maintaining torque. It's a pretty good design, and if I ever need to re-build mine I'll be giving this a shot.


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## krough (Oct 7, 2004)

That's cool. Fortunately I have a 4 RPM AC motor to work with, that has about 10 inch pounds of torque. I am hoping thats enough to lift the lid. Ill let you know how it all turns out. Finishing the FCG tonight. Lots of work left, too little time.

Krough


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## shadow (Aug 9, 2004)

*shaking cage*

Zombie
Thanks for the plug on the MITB....my wife absolutely loved yours and demanded that I make one this year. I wanted to add to the effect by having a hand extend out but it wasn't going to work out this year. I could have bought a new air cylinder that would have made it work but the money just wasn't there this year.

Krough
Z is right...lower rpm is better. 2 Revolutions per second is still fast...and the weight does not have to be great. I generally use an all thread rod u-bolted to the motor shaft and at the end I use lock nuts and weight it using washers or pieces of metal. Too much weight can hurt the bearings in the motor.


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## krough (Oct 7, 2004)

*Finished*

I got the MITB done last night. The 4 rpm dayton works just fine. I made the cog and rod out of wood, the nice benefit to this is that when the when the lid starts to open the friction of the rod and the cog makes a great creaking noise. Thanks for the pointers. Working on a static scarecrow and mr thifty's cage today.

Krough


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## Lotus (Nov 12, 2004)

How much do you think a Mr. Thrifty Skeleton cost beacuse I am kinda low on the $$$$$$ right now.


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## Zombie-F (Apr 12, 2004)

Lotus said:


> How much do you think a Mr. Thrifty Skeleton cost beacuse I am kinda low on the $$$$$$ right now.


They're around $22 from ACC (for 4th quality), but you can probably do better if you search on eBay or just search the web for other vendors.


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## Lotus (Nov 12, 2004)

Zombie-F said:


> They're around $22 from ACC (for 4th quality), but you can probably do better if you search on eBay or just search the web for other vendors.


Which one did you get Zombie the 4th Quality, I want to get the same thing you bought.


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## Zombie-F (Apr 12, 2004)

Oh god yes! As a haunter, I don't really care if some of the bones have plastic burrs, or if some of the bones are a bit off-color, so 4th quality is the way to go Sometimes, you'll get one that's missing a screw or two, but a trip to the hardware store will fix that easily enough.

Just for a price comparison, the 1st quality ones are $50!!!


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## Lotus (Nov 12, 2004)

I might do both cause I made 200 last night in a poker game    Its good to play your older brother


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## Lotus (Nov 12, 2004)

An idea came to me while I was Sleeping during my English class. I got the Idea to Create a Skeleton in the Cage but use a Bucky Skeleton (4th Quality), and also make it a talking Bucky. I know I could Use a Mr. Thrifty but I want a Life Size Skeleton.     I might do both Have a Bucky Skeleton (4th Quality) one and a Mr. Thrifty Skeleton bot in a Cage on either Side of my Huge Spider Web.


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## Zombie-F (Apr 12, 2004)

Lotus said:


> An idea came to me while I was Sleeping during my English class. I got the Idea to Create a Skeleton in the Cage but use a Bucky Skeleton (4th Quality), and also make it a talking Bucky. I know I could Use a Mr. Thrifty but I want a Life Size Skeleton.     I might do both Have a Bucky Skeleton (4th Quality) one and a Mr. Thrifty Skeleton bot in a Cage on either Side of my Huge Spider Web.


You'll need a much sturdier cage and far more powerful motor for a full-sized bucky. I also wouldn't really try to animate the jaw if you're going to have it shake as you may wind up putting undue stress on the jaw motor and cause it to burn out.

If you do try it, be sure to share you experience with it.


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## Lotus (Nov 12, 2004)

Ok thanks I will think about what I should do now


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## Zombie-F (Apr 12, 2004)

Just try and keep in mind a Bucky is 5'4" and weighs somewhere in the neighborhood of 20 - 30 lbs. A thrifty, on the other hand, is only about 3' tall and weighs 7 - 10 lbs (if even that much).

With a hanging cage, it's much easier to work with a Thrifty; he's light and easy to manage. On the other hand, if you just wanted to build a cage that sits on the ground and just wanted the skeleton to talk, a Bucky would be very suitable for that purpose.

If a full-sized Bucky has been done in a hanging cage, the place to ask would be the members of the Halloween-L Mailing list, or the masters at Methodz of Madness.


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## Lotus (Nov 12, 2004)

Nah, I am going to do the same thing as you and make 2 of them


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## Zombie-F (Apr 12, 2004)

Great news! For those of you who can't read a schematic, but CAN assemble pre-made electronic kits, there is a DC Motor Speed control circuit available from the kitsrus people. Kit 67 is the perfect way to power the 12VDC motor used in this project, and you don't need to go to Radio Shack and buy a prototype board to use!

The kit comes with printed circuit board and all parts necessary to build the project. You only need to have the equipment and know-how to solder to build this circuit.

I highly recommend this kit over the prototype I have used. The circuit I use just regulates the voltage to the motor which means it's not being driven with full-torque. Often times, the motor spins at different rates from one trigger of the circuit to the next making for inconsistent rates of shake for the skeleton inside. The advantage of this kit is it spins the motor at full-voltage, but it pulses the signal sent to the motor. So, for slower speeds, it sends short bursts of voltage to the motor and for faster speeds it sends longer bursts of voltage to the motor.

If you want to further simplify this project, I also suggest using a DC PIR circuit I found made by the same company. Kit 30 is a Infrared Sensor similar to the ones that Halloween prop-meisters usually "hack" to work with their stuff, except this one runs off of DC voltage so you can run it off the same power supply that the motor controller runs off of.

This kit also features a more adjustable "on" time than the (very limited) switch on the Hardware Store variety. The "on" time is adjusted via a potentiometer on the board.

Another great feature about the Kit 30 is the fact it has a 30 second "off" time after the "on" time has expired. This makes it so it can't be triggered again for 30 seconds. The advantage here is the same patron can't trip the thing over and over again.

If you use the Kit 30 sensor, I'd also suggest using a kit 43 Relay to send power to the motor. The kit 30 isn't recommended for "mains power switching", so what you do is have the PIR sensor trigger the kit 43 Relay which sends the positive power from the motor controller to the motor.

I'll draw a block diagram of all this someday.


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