A pumping heart prop

Discussion in 'Scenery, Props, and Rigging' started by thisisnotmybeautifulwife, Aug 5, 2019.

  1. thisisnotmybeautifulwife

    thisisnotmybeautifulwife Member

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    Los Angeles, CA
    Hi Everyone,

    New member here, and though I have been a scenic carpenter for almost half of my life, I'm a bit lost when it comes to special FX props. I don't know much about small dc motors or where to start exactly. I purchased a kit off of Amazon, (see link below), to play with and figure if I can try to make something work, but everything I try rotates too fast. I'm just not getting that same pumping effect.


    The end goal: Have a portable pumping (and glowing) heart that the actor has in their costume. Not long after they turn their back to the audience and put said heart into a manila envelope. It should also glow and pump in the envelope. Additionally, it cannot be controlled by any console, it should be able to be turned on by the actor on stage. The thing that will contain the mechanism doesn't need to be seen, as long as it's about the size of a human heart.

    I'm truly stumped. Everything online, that I can find so far, is for film or stays attached to the actor. Any feedback would be much appreciated. I've got that little kit, and red bike lights so far.

    RonHebbard likes this.
  2. Amiers

    Amiers Renting to Corporate One Fixture at a Time.

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    Lighting Floor Tech
    Phoenix, Az
    What is your heart made of?

    What have your tried so far?

    What is the longest length of your human heart?

    Here is my idea but your answers will prolly help.

    First things first if your motors are spinning to fast if you need to “gear down”

    You can use almost dead batteries and pray or half dead and still be fine.

    Next attach yourself some longer arms on 2 sides.


    As the arms drag across the inside of the heart it will mimic beating heart.

    This method won’t work with full charge batteries as it might rip your heart.

    Idea 2. Attach your arms to the heart itself and have the arms attached to the shaft and as it rotates it pulls the heart walls in.

    Idea 3. Add a PWM circuit on to the power and crank it way down to desired speed. Then use the way that you are using it already.
    RonHebbard likes this.
  3. DrewE

    DrewE Active Member

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    Here's some potential inspiration: https://www.sciplus.com/pumping-heart-model-kit-50-p

    Could the actor/actress control it with a rubber squeeze bulb in their pocket connected by a hose or tube? It sounds tricky to work out the routing of the tube; maybe down a sleeve and then up the outside of the same sleeve to the chest. The prop itself could be little more than a balloon or rubber glove or something of that ilk that expands and contracts due to water or air or whatever being pushed in and out with the bulb. Maybe wires could be run along the tube for the flashing lights, or use some sort of a pressure sensor to activate them.

    It would take some practice, I think, for the performer to be able to operate the bulb without attracting undue attention to that movement.

    (Like most any off-the-cuff idea, this may be totally unworkable in practice...caveat lector.)
    RonHebbard likes this.
  4. kicknargel

    kicknargel Well-Known Member

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    Denver, CO
    One go-to source for a lot of this stuff is Arduino. I don't have a ton of experience myself. Or, Lego Technik could be a source for small low-speed motors.
    RonHebbard and Van like this.
  5. Van

    Van CBMod CB Mods Premium Member

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    Project Manager, Stagecraft Industries, Inc.
    Portland, Or.
    Check out Adafruit.com tons of resources for Arduino, RaspberryPi, motor control, LED control etc etc. even the simplest of arduino style boards, and they are tiny, could handle the PWM necessary to control a small motor and the LEDs.
  6. SHCP

    SHCP Active Member

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    Technical Director
    San Francisco

    I used this kit to make a clock works turn. It had a nice slow speed and is a very small unit including the 9 volt battery. (buy that and a case separately)

    I would mount it vertically and mount it inside a rubber heart https://www.amazon.com/dp/B07545Q6HD/?tag=controlbooth-20

    or https://www.amazon.com/dp/B00VIU8K3A/?tag=controlbooth-20

    Or make your own I guess. Could be fun.

    Anyway, mount a disc off center on the axle and when it turns it might look like the heart is beating. I think. Here are some images of the idea:

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