Final Design

Final Model

Steps toward improving the second prototype and developing our final model consisted of the implementation of arm movement, integration of electronics, and construction of a wooden frame.

Solidworks animation

https://dl.dropboxusercontent.com/u/58857266/CAD%20Model/Resources/CAD%20Model.mov

Video of final model

https://dl.dropboxusercontent.com/u/58857266/IMG_0778/Resources/IMG_0778.mov

Arm Movement

Acrylic linkages connected the axle of the boulder to Sisyphus' hands. Sisyphus' biceps are connected to his thigh by a thin metal rod. This both couples and synchronizes the movement of the arms with the movement of the legs. 

Electronics

We used a microcontroller (Arduino Uno) and an Adafruit Motor Shield for Arduino to drive the motor. PWM is used to control the speed of the motor and a potentiometer is used to adjust the PWM. The motor encoder feedback is monitored by the Arduino to create a soft emergency stop. The monitor counts the rising edges of the encoder. If the counts remain the same for a select period of time, in our case 200 ms, the power to the motor is turned off. This feature prevents further damage to the mechanism in case the linkages or other mechanical features cease to function properly. The system runs on a 12V wall adapter power supply. 

Side Panel of Frame

 The 12V power supply connects to the power jack on the Arduino, the potentiometer (black knob) changes the speed of the mechanism, and the switch turns the mechanism on and off.