Hi all I'm from Bioengineering and unfortunately not too expert on the mechanical side. I'm making a device for which I need a mechanism to transform circular motion into oscillatory motion. I found the mechanism in the picture below: http://www.clohe-movingtoys.eu/Images/Mechanisms/leva_oscillante_1.gif [Broken] In my device, the oscillating 'stick' would cover an angle of 170 degrees. My questions are: Is the oscillatory motion actually sinusoidal? (ie is the velocity/position actually sinusoidal, or are they just approximated to sinusoids due to the small angle shown in the picture?) If it is/can be sinusoidal, is there a straight forward way to go about to find the specs (size and position of rotating wheel...) of the system? Suggestions on different mechanisms I could use are very welcome. (I thought of using a cam but the oscillating 'stick' would in my case probably be jumpy due to the high velocity and low weight needed). Thanks everyone!!