Building Your First Robot Arm with Arduino

Introduction

Building a robot arm is one of the most rewarding projects for anyone interested in robotics. It combines mechanical design, electronics, and programming into a single hands-on build. In this tutorial, we'll create a 3-axis servo-controlled arm that you can command via serial input.

Parts You'll Need

Mechanical Assembly

• Print the parts — download the STL files from our GitHub repo
• Mount the base servo — this controls rotation
• Attach the shoulder and elbow segments — use servo horns and M3 screws
• Secure all connections — a wobbly arm won't repeat positions accurately

Wiring

Arduino Pin → Servo Signal
────────────────────────────
D9 → Base servo (rotation)
D10 → Shoulder servo
D11 → Elbow servo

5V Supply → Servo VCC (all)
GND → Servo GND + Arduino GND

Important: Never power servos directly from the Arduino's 5V pin — the current draw can damage the board.

The Code

#include <Servo.h>

Servo base, shoulder, elbow;

void setup() {
 base.attach(9);
 shoulder.attach(10);
 elbow.attach(11);
 Serial.begin(9600);
 Serial.println("Robot Arm Ready. Format: B,S,E (0-180)");
}

void loop() {
 if (Serial.available()) {
 String input = Serial.readStringUntil('\n');
 int b = input.substring(0, input.indexOf(',')).toInt();
 int s = input.substring(input.indexOf(',') + 1, input.lastIndexOf(',')).toInt();
 int e = input.substring(input.lastIndexOf(',') + 1).toInt();

 base.write(constrain(b, 0, 180));
 shoulder.write(constrain(s, 0, 180));
 elbow.write(constrain(e, 0, 180));
 Serial.println("Moved!");
 }
}

Next Steps

• Add inverse kinematics for coordinate-based control
• Attach a gripper for pick-and-place tasks
• Upgrade to stepper motors for higher precision

Happy building!