The creation of a piece of hardware like this Motor Board allows not just to perform the functions requested in the original project description, but also to just control motors, either stepper motors, or DC ones. [Since all our work was done around the use of DC motors for force-feedback control, this document will only focus on how to drive those]

Motors are characterized by different variables. DC motors are those that don't have any limitations in terms of how many degrees they can be moved around their shaft. One important variable to look into is the range of voltage the motor needs to operate with. For example the small motors we find in car toys work in a range between 2 or 3 volts and up to 7 or 8 volts

Since microprocessors work typically with 5 volts (and so does the wiring board), one may think that it could be enough to connect the output of one pin of the microprocessor to the motor in order to provide it with enough voltage to start the movement. Unfortunately it is not that easy. Motors require quite a high amount of current, in the range of mili-amperes before they start to move, while the typical processors drive currents far under that level

This means that we are going to need an interface between the logics of our circuit (the microprocessor) and the motor. There are different techniques. Here we will explain just three easy tricks that may be valuable for interaction designers in different situations:

- turn motors On-Off using relays

- change speed in motors using PWM and Darlington pairs

- change direction using H-bridges