**1. How to Implement a Servo Motor with Arduino Nano (Step by Step)**
**1.1 Understand the servo interface (what really matters)**

A standard RC servo has three wires:

* Signal – PWM control from [Arduino](https://www.ampheo.com/c/development-board-arduino)
* VCC – Servo power (usually 4.8–6 V)
* GND – Ground reference


Critical rule:

The servo’s signal ground must be common with Arduino ground, even if the servo uses an [external power supply](https://www.onzuu.com/category/external-internal-power-supply).

The control signal is:

* 50 Hz PWM (20 ms period)
* Pulse width typically:
* ~1.0 ms → 0°
* ~1.5 ms → 90°
* ~2.0 ms → 180°

**1.2 Wiring for a small servo (direct, low-risk setup)**

Use this only for micro servos with very low current draw.

Connections:

* Servo Signal → Arduino Nano D9 (or any PWM-capable pin)
* Servo VCC → Arduino 5V
* Servo GND → Arduino GND

Limitation:

* [Arduino Nano](https://www.ampheo.com/product/a000005-25542476) 5V rail cannot supply high peak current
* Risk of reset or USB disconnection if the servo stalls

**1.3 Wiring with an external power supply (recommended)**

This is the correct method for most real projects.

Connections:

* Servo Signal → Arduino Nano D9
* Servo VCC → External 5–6 V supply
* Servo GND → External supply GND
* Common GND between Arduino Nano and external supply

Why this works:

* Servo current spikes are isolated
* Arduino remains stable
* Allows use of medium or high-torque servos

**1.4 Basic Arduino code (minimal, reliable)**

#include <Servo.h>

Servo myServo;

void setup() {
  myServo.attach(9);   // PWM pin
}

void loop() {
  myServo.write(0);    // 0 degrees
  delay(1000);
  myServo.write(90);   // 90 degrees
  delay(1000);
  myServo.write(180);  // 180 degrees
  delay(1000);
}

Implementation note:
The Servo library uses Timer1, so avoid conflicts with other timing-critical libraries.

**2. Common Problems and How to Fix Them**

| Symptom | Root Cause | Fix |
| ------------------ | ---------------------------- | --------------------------------- |
| Servo jitters | Floating ground or noise | Ensure common GND, add decoupling |
| Arduino resets | Servo draws too much current | Use external power |
| Servo doesn’t move | Wrong PWM pin or wiring | Verify signal pin |
| Random motion | Power rail noise | Add bulk capacitor (470–1000 µF) |

**3. Real Component Selection (Practical Examples)**

Below are real-world servo choices and supporting components, with selection logic tied to reliability and procurement.

**Example A: Micro Servo (Learning / Prototyping)**

Use case:
Small robotics projects, indicators, light mechanical loads.

* Servo: SG90 Micro Servo
* Voltage: 4.8–6 V
* Stall current: ~650 mA
* Torque: ~1.8 kg·cm

Connection:

* Can run from Arduino 5V only if lightly loaded
* External supply strongly recommended for stability

Why choose it:

* Cheap, widely available
* Huge community support
* Low procurement risk

**Example B: Metal-Gear Servo (Medium Load)**

Use case:
Robot arms, pan–tilt cameras, mechanical linkages.

* Servo: MG996R Servo Motor
* Voltage: 4.8–7.2 V
* Stall current: up to 2.5 A
* Torque: ~11 kg·cm

Power requirement:

External 5–6 V supply is mandatory

Why choose it:

* High torque at low cost
* Metal gears survive shock loads
* Common in industrial prototypes

**Example C: Power Supply Selection for Servos**

Recommended power options:

| Option | When to Use |
| ----------------------- | ------------------- |
| 4×AA NiMH pack | Mobile, low noise |
| 5V buck converter (≥3A) | Embedded systems |
| 6V BEC module | RC/robotics systems |

Engineering rule:

Size the supply for stall current × number of servos, not average current.

**Example D: Protection & Stability Components**

| Component | Typical Choice | Purpose |
| ------------------------ | ------------------------ | ---------------------------- |
| Bulk capacitor | 470–1000 µF electrolytic | Absorb current spikes |
| Bypass [capacitor](https://www.onzuu.com/category/capacitors) | 0.1 µF ceramic | Reduce high-frequency noise |
| Series [resistor](https://www.onzuu.com/category/resistors) (signal) | 220 Ω | Suppress ringing |
| Flyback [diode](https://www.onzuu.com/category/diodes) | Not needed | Servos have internal drivers |

**4. Pin and Timing Considerations on Arduino Nano**

* Any digital pin can control a servo
* Best practice: use D9 or D10 (Timer1-based)
* Maximum practical servos on Nano: 4–6, depending on power supply

For more than 6 servos:

* Use an external PWM driver (e.g., [PCA9685](https://www.onzuu.com/search/PCA9685))
* Reduces CPU load and timing jitter

**5. Final Engineering Takeaways**

* Never power medium or large servos from the Nano’s 5V pin
* Always share ground between Arduino and servo supply
* Choose servos based on stall current and torque, not size
* Add bulk capacitance close to the servo connector

In short:

The [Arduino](https://www.ampheoelec.de/c/development-board-arduino) controls the servo.
The power supply determines whether it works reliably.