Temporal Demo 2: Pratfall

The device to demonstrate pratfall is a simple bridge that collapses upon activation of the motor. On one end the bridge is held in place by a pivot that is inserted into the base. The other end is held up by the motor. This follows the Articulated Support Structure system type. When the motor rotates, it makes the bridge pivot such that the side where the motor is no longer supporting falls to the base. The bridge is kept simple and lightweight to reduce the stress placed on the motor shaft.

The bridge is constructed using 6mm plywood that is cut into specific shapes. The motor mount and the pivots are held to the base by rectangular tabs whose minimal tolerance means that friction largely holds the system in place. The lasercutter cannot cut in two dimensions so the bridge despite being fitted into a pivot with a round hole articulates using a square insert. The hole in the pivot is large enough to allow the bridge to freely rotate.

In the video demonstration I did not have a screwdriver to fasten the motor to the holder and hence had to hold it in place. The final demonstration in class will feature a rigidly-mounted motor.

CODE:

/*importing library*/
#include “Servo.h”;
/*SERVO_PIN is the output pin from the board*/
const int SERVO_PIN = 9;
/*Servo is called Demo1*/
Servo Demo1;
void setup() {
Serial.begin(115200);

Demo1.attach(SERVO_PIN);

}

void loop() {
Demo1.write(0);
delay(4000);
Demo1.write(90);
delay(4000);

}

The code above is a modified version of that from Demo 1.

VIDEO:

FILES:

Demo2_vsanand