While essential for life, few of us have seen a beating heart in real life. Given that this normally involves some sort of trauma, or radical corrective surgery, this is certainly for the best. If, however, you’d like an extremely realistic working model of this essential organ, Will Cogley shows how he created his own.
The amazing animatronic is cast out of silicone, then covered in some sort of fake blood. Inside, two servos push the bottom left and right sides of the heart out in an offset sinusoidal pattern, then snap back as quickly as possible. A third servo pushes the top of the heart out, following the motion of the bottom two, and completing the beating effect. The 3D-printed device is controlled by an Arduino Micro board, along with an Adafruit I2C servo driver, and user interface is provided by a potentiometer to vary the heartbeat speed. Power is supplied via a cable from the back, which allows it to sit on a table or in one’s hands without ruining the effect.
If that’s too realistic for your tastes, Cogley also built a much simpler model using only a motor/crank mechanism to incrementally push out sections of the heart. This is housed in a cloth heart-shaped enclosure and battery-powered, making it more of a lighthearted joke than a realistic and/or terrifying prop.