Dialectical Data
~/workshop $ cat ./inventory/sg90-micro-servo/README.md

SG90 Micro Servo (9g)

category
Actuator
qty
1
status
owned / untested
maker
Generic/unbranded (the "SG90" designation is a de facto industry-standard name for this exact servo class — TowerPro's original SG90 is the reference, but this blue-case unit isn't confirmed genuine TowerPro)
SG90 Micro Servo (9g)

Overview

The extremely common 9-gram plastic-gear hobby servo — used everywhere from RC models to countless Arduino “sweep” tutorials. 3-wire interface (power, ground, PWM signal), ~180° of rotation (some clones limit to ~120°), plastic gear train (not metal-gear, so not rated for sustained heavy load).

Key specs

  • Weight: ~9g
  • Operating voltage: 4.8–6V typical for this servo class
  • Rotation range: ~180° (varies slightly clone-to-clone; some SG90-class servos are closer to 120°)
  • Stall torque: ~1.6–1.8 kg·cm at 4.8V (typical for class, not confirmed for this specific unit)
  • Speed: ~0.1 sec/60° at 4.8V (typical for class)
  • Gears: plastic

Pinout

3-wire cable (color order per the supplied photo, standard for this servo class):

Wire Function
Brown GND
Red VCC (4.8–6V)
Orange Signal (PWM)

Wiring / typical usage

Signal wire to any PWM-capable GPIO, power from a 5V rail capable of handling the servo’s stall current spike (don’t power directly from a microcontroller’s onboard 5V regulator if driving more than one servo or expecting load — use a separate 5V supply with common ground back to the MCU). Control via a standard ~50Hz PWM signal, pulse width ~1-2ms mapping to position (library-dependent, see below).

Code / libraries

  • Arduino: built-in Servo library — myServo.attach(pin); myServo.write(angle);
  • ESP32/ESP-IDF: ESP32Servo library (the stock Arduino Servo library isn’t ESP32-compatible without it)
  • MicroPython: machine.PWM driven manually, or a dedicated servo helper library

Source material

  • Case label (“MicroServo 9g SG90”) read directly from the supplied photo — high confidence on part identity.
  • General SG90-class specs (torque, speed, voltage range): widely standardized across the hobby servo market, consistent with typical TowerPro SG90 datasheets referenced across community sources.
  • Product photo: /inventory/sg90-micro-servo/product-photo.jpg — the actual owned unit.

Verification

Case label read directly from photo — high confidence this is an SG90-class servo. Torque/speed specs are typical-for-class figures, not measured or confirmed for this specific unit — treat as a starting assumption, not a guarantee, especially since exact rotation range (180° vs ~120°) varies between SG90 clones.

Notes / gotchas

  • Plastic gears — don’t force rotation past its mechanical limit or stall it under load for extended periods, gear teeth strip easily on this class of servo.
  • Confirm actual rotation range (some clones stop well short of 180°) before assuming a specific angle range in code.