Whenever we talk about moving from one place to another, we think about wheels and similarly whenever we think about moving the wheels of a robot, we think about motors. There are various different types of motors that exist. So let's firstly look at the most basic type of motor, which is called a brushed DC motor. As the name suggests, it works on a direct current. You may find such motors like this:

Trust me, these things are omnipresent, from the Christmas gift you bought for your neighbor to the biggest baddest machines out there—you will find these motors hiding under the hood. These motors are common for a reason and that is because they are very, very simple. So simple that powering them up only requires a battery and two wires. Simply connect the positive to one terminal and negative to the other, and the motor will start spinning. Interchange those connections and the direction of the rotation will change. Take two cells and double the voltage and the motor will spin even...