This TowerPro SG90 Continuous Rotation 180 Degree Servo Motor is special among all the available servo motors because its operation is very different from that of a standard servo. As instead of going to a specified angle, this servo will be static at a 1.5ms pulse, a longer pulse gives forward rotation and a shorter pulse give backward rotation. It equips Carbon Fiber Gears which makes the servo motor much lighter than same metal gear motor. It is a Digital Servo Motor which receives and processes PWM signal faster and better. It equips sophisticated internal circuitry that provides good torque, holding power, and faster updates in response to external forces.
To make this motor rotate, we have to power the motor with +5V using the Red and Brown wire and send PWM signals to the Orange colour wire. Hence we need something that could generate PWM signals to make this motor work, this something could be anything like a 555 Timer or other Microcontroller platforms like Arduino, PIC, ARM or even a microprocessor like Raspberry Pie. the PWM signal produced should have a frequency of 50Hz that is the PWM period should be 20ms. Out of which the On-Time can vary from 1ms to 2ms. So when the on-time is 1ms the motor will be in 0? and when 1.5ms the motor will be 90?, similarly when it is 2ms it will be 180?. So, by varying the on-time from 1ms to 2ms the motor can be controlled from 0? to 180?.
Used as actuators in many robots like Biped Robot, Hexapod, robotic arm etc..
Commonly used for steering system in RC toys.
Robots where position control is required without feedback.
Less weight hence used in multi DOF robots like humanoid robots.