App note from Precision Microdrives teaching you ways to drive vibration motors. Link here
Using a PWM signal to drive vibration motors can enable high-performance vibration control with relative ease. PWM signals are a common feature in many microcontrollers, and simple programs can adjust their frequency and Duty Cycle. These programs can be used to create complex PWM waveforms, and store them for later use.
Typical microcontrollers cannot provide enough current, and in some cases voltage, to drive a vibrating motor. It is therefore recommended that they be used in conjunction with drive circuitry, examples of which are provided in the appropriate sections and more information can be found in other motor application notes.