| In robotics, three motors are generally used; the direct | | | | choice from the project. |
| current (DC), stepper and radio controlled ('RC') servo | | | | For a DC, applying DC voltage will rotate the shafts, |
| motors. | | | | continuously clockwise and anti-clockwise (reverse |
| Servo motors are used in most robotic projects. | | | | polarity DC voltage). Even a H-bridge circuit is needed |
| Reasons include its high accuracy and degree of | | | | for the reverse (anti-clockwise) mechanism. Degree of |
| control with pulse width modulation ('PWM'). Compared | | | | controls needed for a high precision project like a |
| with other common motors; DC and stepper motors, | | | | robotic arm and therefore the DC type is not suitable. |
| servo motors are the clear choice for projects | | | | Put in a simple way, DC motors simply rotate |
| requiring specific movements. | | | | continuously as long as given power. While servo |
| Inside a stepper type, lie a series of coils. These coils | | | | motors are smarter than DC motors because they |
| create magnetic field that respond to permanent | | | | can be programmed to turn in specific amount of |
| magnets, in turn creating rotations. To control the | | | | angles. Stepper motors are hardly used and is the |
| rotation, coils must be switched on (rotate forward) | | | | least popular. A common way to get a free stepper |
| and off (reverse) constantly. Sequence of (or phase | | | | motor is from old floppy disk drives or 'CD-rom' drives. |
| pattern) 'ons' and offs turn the stepper motor. The | | | | These are good sources for reaping a free stepper |
| stepper type is not too widely available. A lack of | | | | motor. |
| familiarity with these motors' application eliminates its | | | | |