Servo Motors

A servo turns to an exact angle and holds it, which makes it the motor for robot arms, grippers, steering, pan-tilt camera mounts and lids that open on cue.

A hobby servo has three wires (power, ground and signal) and is controlled by a PWM pulse from your board. The Arduino Servo library, or an ESP32 servo library, handles the timing, so you simply write an angle.

  • SG90-class micro servos are small, light and plastic-geared, ideal for light loads and learning.
  • MG996R-class servos have metal gears and much more torque, for arms and heavier mechanisms.

How to choose:

  • Pick by the torque your mechanism needs, then by size and gear material.
  • For continuous spinning, use a DC or gear motor instead. For exact steps, use a stepper.

Servos draw surges of current when they move. One micro servo can run from a board for a quick test, but several servos need their own 5V supply with ground shared to the Arduino or ESP32. Otherwise the board resets or the servos jitter.

Frequently asked questions

SG90 or MG996R?

The SG90 for light loads and learning. The MG996R's metal gears and higher torque suit arms and heavier mechanisms.

Why does my servo jitter?

Usually power. Give servos their own 5V supply and share ground with the board.

Servo, stepper or DC motor?

Servo for exact angles, stepper for exact steps, DC for continuous spin.

How many servos can an Arduino run?

The signal pins are no problem. The limit is power, so use a separate supply for more than one.

Guides

Reference pages on soldr.ai

More guides on soldr.ai

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