Beginner Project: Build a Spider Robot (Quadruped) with Arduino - Beginner Project: Build a Spider Robot (Quadruped) with Arduino

🕷️ Beginner Project: Build a Spider Robot (Quadruped) with Arduino

The Spider Robot (also called a quadruped robot) is a fun project where you build a 4-legged walking robot controlled by an Arduino.
Each leg has two servo motors:

One for the hip joint (forward/backward)

One for the knee joint (up/down)

With coordinated movements, the robot can walk forward, backward, turn, and even dance.

🛠️ Components Required

Arduino UNO (or Nano)

8 × SG90/MG90S Servo Motors (2 per leg)

Robot chassis (3D printed or wooden)

HC-05 Bluetooth Module (optional, for remote control)

Battery Pack (5V – 7.4V Li-ion or AA)

Jumper wires

Breadboard (optional)

Pin Connections

Component	Arduino Pin	Notes
Front Left Hip	D2	Servo
Front Left Knee	D3	Servo
Front Right Hip	D4	Servo
Front Right Knee	D5	Servo
Back Left Hip	D6	Servo
Back Left Knee	D7	Servo
Back Right Hip	D8	Servo
Back Right Knee	D9	Servo
HC-05 TX	D10	Optional Bluetooth
HC-05 RX	D11	With divider
Power	5V & GND	All servos + Arduino common ground

🔌 Circuit Diagram

👉 The spider robot uses 8 servo outputs from Arduino + optional HC-05.
(I can make a beginner-style wiring diagram for this like we did for the 4-motor car if you want visuals.)

💻 Arduino Code (Basic Walking Pattern)

#include <Servo.h>

// — Servo objects for 4 legs (2 per leg: Hip and Knee) —
Servo FL_Hip, FL_Knee; // Front Left
Servo FR_Hip, FR_Knee; // Front Right
Servo BL_Hip, BL_Knee; // Back Left
Servo BR_Hip, BR_Knee; // Back Right

// — Setup Function —
void setup() {
// Attach each servo to its respective pin
FL_Hip.attach(2);
FL_Knee.attach(3);
FR_Hip.attach(4);
FR_Knee.attach(5);
BL_Hip.attach(6);
BL_Knee.attach(7);
BR_Hip.attach(8);
BR_Knee.attach(9);

// Set all servos to neutral center position
centerPos();
}

// — Main Loop —
void loop() {
walkForward();
delay(2000);

walkBackward();
delay(2000);

turnLeft();
delay(2000);

turnRight();
delay(2000);

dance();
delay(2000);
}

// — Center all servos —
void centerPos() {
FL_Hip.write(90); FL_Knee.write(90);
FR_Hip.write(90); FR_Knee.write(90);
BL_Hip.write(90); BL_Knee.write(90);
BR_Hip.write(90); BR_Knee.write(90);
}

// — Movement Functions —

// Walk Forward
void walkForward() {
// Step 1: Lift front left & back right legs
FL_Knee.write(60);
BR_Knee.write(60);
delay(300);

// Move them forward
FL_Hip.write(120);
BR_Hip.write(120);
delay(300);

// Drop them back down
FL_Knee.write(90);
BR_Knee.write(90);

// Step 2: Lift front right & back left legs
FR_Knee.write(60);
BL_Knee.write(60);
delay(300);

// Move them forward
FR_Hip.write(60);
BL_Hip.write(60);
delay(300);

// Drop them back down
FR_Knee.write(90);
BL_Knee.write(90);
}

// Walk Backward
void walkBackward() {
// Step 1: Lift front left & back right legs
FL_Knee.write(60);
BR_Knee.write(60);
delay(300);

// Move them backward
FL_Hip.write(60);
BR_Hip.write(60);
delay(300);

// Drop them back down
FL_Knee.write(90);
BR_Knee.write(90);

// Step 2: Lift front right & back left legs
FR_Knee.write(60);
BL_Knee.write(60);
delay(300);

// Move them backward
FR_Hip.write(120);
BL_Hip.write(120);
delay(300);

// Drop them back down
FR_Knee.write(90);
BL_Knee.write(90);
}

// Turn Left
void turnLeft() {
// Rotate hips to pivot left
FL_Hip.write(120);
BL_Hip.write(120);
FR_Hip.write(120);
BR_Hip.write(120);
delay(500);

// Return to center
centerPos();
}

// Turn Right
void turnRight() {
// Rotate hips to pivot right
FL_Hip.write(60);
BL_Hip.write(60);
FR_Hip.write(60);
BR_Hip.write(60);
delay(500);

// Return to center
centerPos();
}

// Fun Dance Movement
void dance() {
for (int i = 0; i < 3; i++) {
// Alternate knee positions for a fun effect
FL_Knee.write(60);
FR_Knee.write(120);
BL_Knee.write(120);
BR_Knee.write(60);
delay(300);

// Return to center
centerPos();
delay(300);
}
}

Video

📱 Bluetooth Control (Optional)

You can add an HC-05 Bluetooth module and modify the code to accept commands:

F → Walk Forward

B → Walk Backward

L → Turn Left

R → Turn Right

D → Dance

(Just like we did for your car and humanoid projects.)

🤝 Teamwork Idea

Team A: Assemble chassis and mount 8 servos

Team B: Do wiring to Arduino + power supply

Team C: Upload code and test walking patterns

Conclusion

Congrats 🎊! You have built a Spider Robot (Quadruped) 🕷️.
This project teaches servo coordination, gait patterns, and Arduino coding, and can be expanded with Bluetooth, sensors, or remote control.