Simple mechanism for intermittent 180 deg. rotation

Input: horizontal cam shaft. Output: green rectangle that rotates intermittently. It has prismatic joint with blue vertical shaft of two motions (up-down and rotary). Orange bar angularly positions the vertical shaft. Unusual thing: 2 (cam and friction drives) in 1. In one revolution of the input the green rectangle rotates 180 deg., a thing that ordinary Geneva mechanisms can not get. Disadvantage: considerable wear when the vertical shaft does not rotate. STEP files of this video: Inventor files of this video: