Manipulating a 2 DOF Arm

First, I had to quickly build a 2 DOF robot arm that uses two -90 to 90 degree servos. The end effector has an LED that can draw with the help of long exposure photography. 

CAD

First, I made sure the arm was working and  could go to specified angles. In the image below, a messy star shape is drawn this way

I quickly realized that the -90 to 90 degree range resulted in a very inconvenient workspace. With an envelope analysis in Matlab, I determined that 0 to 180 degrees is a better operating range. 

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