i have a little project going on, where i want to connect vibration motors to an arduino. I found this, with example code but also found other tutorials wish use a capacitor for the motor. What is the advantage of using one ?
I am currently planning to power the arduino by a 9V battery, with 3 ultrasound sensors being connected to the 5v output of the arduino. Hence, i believe that i need an external battery for the 2 vibration motors. I think 2x AA's should do the job for some hours, right ?
I also have a question about the rating of the resistor to use at the base of the transistor. How do i calculate the rating that i need ?