Solutions Cubed, LLC writes:
In a generic electronic system there are some inputs that are controlled by the end user. These inputs are read by electronics and acted upon by using outputs. The inputs can come from a myriad of sources: buttons, switches, sensors, relays, and communication devices, to name a few. In certain environments and situations, these input signals can pose a threat to the electronics reading them – especially if those electronics are designed without thought of protection. One such environment is the world of industrial electronics.
An important aspect of designs for this environment is interfacing sensitive electronics with inputs coming from the harsh conditions of a factory floor. Usually, inputs are read by some sort of intelligent processor such as a microcontroller, FPGA, or state machine. In cases like these, it is imperative to protect the processor from the inputs, while still providing a usable signal for the processor to read.
Protecting Inputs in Digital Electronics - [Link]
Servo motor is very useful in robotic. I used servo motors to create few robots in the past. But I never think of using servo motor as input device, and mahto did it. Making servo motor as input device, you can now record the position of the servo motor and play it back the sequence of actions afterward. [via]
Servo Motor as Input Device - [Link]