Controlling Continuous Servo with ESP32

Continuous Servo practical reference

A servo modified for full continuous rotation rather than fixed-angle positioning, useful as a simple speed-controlled wheel drive.

Key specifications

• Operating voltage: 4.8V - 6V DC (5V typical)
• Control signal: PWM, 50Hz, 1ms-2ms pulse width — but the pulse now sets speed and direction, not angle
• Neutral point: ~1.5ms pulse = stopped; shorter/longer pulses spin one way or the other, further from 1.5ms = faster
• Positioning: None — fully open-loop, no feedback on shaft angle, only continuous rotation
• Typical no-load speed: ~50-60 RPM, varies by donor servo and how it was modified
• Weight: ~9g-55g depending on donor servo (SG90-based vs MG996R-based)

Pinout and connection notes

Every unit's stop point drifts slightly from the textbook 1.5ms. Sweep 1.3ms-1.7ms in code once and hard-code the value that actually stops your specific servo.

• GND: Ground — usually the brown or black wire
• VCC: Power, 4.8V-6V DC — usually the red wire
• Signal: PWM control input — usually the orange or yellow wire

Integration checklist

1. Confirm the exact part number and breakout-board revision.
2. Verify supply voltage, current demand, logic levels, and signal direction against the datasheet.
3. Check controller pin assignments and bus address or interface mode against the example code.
4. Power up with external loads disconnected, then test signals before full integration.
5. If readings or communication fail, check power and ground first, then pin mapping, interface settings, and library initialization.

Troubleshooting and reproducibility

Record the board used, wiring, library/version, supply arrangement, and measured behavior. Use the selected board-specific wiring example as the source of truth. Never assume visually similar modules share identical voltage tolerance or pin order.