Joystick Control Mechanism

To tackle this problem, one must first uncover the underlying principle of operation of the built-in controller. After carrying out rigorous experimentation on the disassembled control unit, it was deduced that it operates according to the principle of electromagnetic induction.

As illustrated in Figure 12, the joystick handle is connected to a coil excited by a sinusoidal voltage and acts like a primary side of a transformer. Underneath the lever lies four coils in each direction (right, left, forward, and backward), which, although electrically isolated from the primary coil, are nevertheless magnetically coupled to it and they behave as the secondary side of a transformer. Consequently, a voltage was induced across each of the four secondary coils based on the rotation of the Joystick.

**Figure 12.** Working principle of existing joystick controller.

Furthermore, moving the joystick in a certain direction changes the coupling (i.e., mutual inductance) between them and the primary coil, thus altering the signals developed on each secondary coil. These signals were then processed to produce movement in the corresponding direction.

To preserve the joystick control capability, we devised a scheme that does not interfere with the built-in controller circuitry and was implemented on the existing joystick controller depicted in Figure 12. The designed system necessitates only three directions (right, left, and forward). There was mechanical arrangement was designed and implemented to control the existing joystick without modifying its functionality. The scheme for controlling the joystick is explained in details in the implementation section.
