We used two Arduino Uno microcontroller boards connected to a 9V battery to power our two servos. The servo used to create the linear motion was a 360º servo while the servo used to create the rotary motion was a 180º servo. Both the linear and rotary motions required less than the 180º which is reflected in our code below. Additionally the code for the linear motion includes a delay between the up and down motion to allow for the rotary motion. Similarly, the code for the rotary motion includes a delay in the beginning to allow the knife to move down before rotating.
Figure 1: Electronics
(a) (b)
Figure 2: Arduino code for servos (a) linear motion, (b) rotary motion