Servo
A hobby servo is a closed-loop positioning actuator: a small motor, gears, potentiometer, and controller board work together to move and hold a shaft angle.
Part images
What it is
A hobby servo is a closed-loop positioning actuator: a small motor, gears, potentiometer, and controller board work together to move and hold a shaft angle.
How students use it
Students use it for arms, pointers, locks, gates, steering, and any project that needs a controlled angle rather than continuous spin.
Pins and power
Typical hobby servo wiring is power, ground, and signal. Verify the wire colors on the actual servo before connecting.
Use appropriate servo power. Do not assume the Pico GPIO can power the servo motor.
SunFounder explains that the signal is pulse-width controlled, with a pulse every 20 ms. Around 1.5 ms is neutral/90 degrees, with typical useful pulses roughly 0.5 ms to 2.5 ms depending on the servo.
Voltage and safety
Servo signal is low-current, but servo power is not. Brownouts happen when a servo pulls more current than the power source can provide.
Do not force the horn past its mechanical limits. Keep fingers clear of linkages and powered mechanisms.
Module internals
Case, output shaft, gear system, potentiometer, DC motor, and embedded control board.
Datasheet notes
SunFounder does not identify one exact servo model number. Match the servo label before using a model-specific datasheet. Key specs are voltage range, stall current, torque, speed, pulse range, and travel angle.
Common libraries
Use machine.PWM to generate servo control pulses. Most lessons wrap this in a small helper function or class.
Common mistakes
Powering the servo from a weak 3.3V pin, no common ground, wrong pulse range causing chatter, reversed power wires, and physically blocking the servo so it stalls.