Steppers with Encoders: When Open-loop Control Isn’t Enough

With the increasing popularity of DIY projects such as quadcopters, CNC tables and 3D printers, many people are faced with the decision of which type of motor to use in their project. For applications that require precise control of the position of the motor, the common choices are DC motors with encoders, servo motors, and stepper motors.

A DC motor is the standard electric motor; it will spin as fast as it can with the DC power you provide it with. On its own, a DC motor has no position control. Most DC motor controllers allow you to change the duty cycle, a value from 0 to 100% that describes how much of your power supply is being made available to the motor. However, controlling the duty cycle does not give you control over the position or even the velocity of the motor. This is where encoders come in:  an encoder…