Halloween animatronic mask - easy

Turn a 3D printed Halloween mask into a simple animatronic project!

Youtube: https://youtube.com/shorts/XTwr7t9wOFc?feature=share

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This project is designed to be easy to build, inexpensive and beginner-friendly, using only two small 9g servos and an ESP32-C3 Mini to control the movement of the eyes.

The mask features two independently controlled moving eyes, creating different animations that make the mask look alive.

No complicated electronics or expensive controllers are required.

Features

•

Fully 3D printed mask

•

2 × 9g micro servos

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ESP32-C3 Mini

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ESP32-C3 Mini expansion board for easier wiring

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Moving left and right eyes

•

5 different eye animations

•

Animations automatically run one after another

•

Each animation lasts approximately 5–6 seconds

•

Can be powered by a battery or USB cable

•

Easy to modify and customize

•

Suitable for Halloween, cosplay, robotics and animatronic projects

The two servos are connected independently, allowing the eyes to move together or in opposite directions.

Required Components

Electronics

•

1 × ESP32-C3 Mini

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1 × ESP32-C3 Mini expansion board

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2 × 9g micro servos

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1 × 5V power source

For power, you can use either:

•

a USB power bank / USB cable

•

a suitable 5V battery solution

Other

•

3D printed mask

•

3D printed eye components

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Small screws or suitable servo mounting hardware

•

Optional hot glue or epoxy for securing components

Servo Connections

The project uses:

Servo 1 – Left eye

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Signal - GPIO 2

•

VCC - 5V

•

GND - GND

Servo 2 – Right eye

•

Signal - GPIO 3

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VCC - 5V

•

GND - GND

Important

The servos should be powered from a suitable 5V supply.

Do not try to power both 9g servos from the ESP32 3.3V output.

If using an external 5V supply, connect:

Power supply GND - ESP32 GND

The ESP32 and servos must have a common ground.

How the Animations Work

The program contains five different animations.

Animation 1 – Fast synchronized movement

Both eyes move together from side to side at relatively high speed.

Animation 2 – Slow synchronized movement

Both eyes move together, but much more slowly, creating a calmer movement.

Animation 3 – Opposite movement

The two eyes move in opposite directions.

For example:

Left eye → right

Right eye → left

Then they reverse direction.

Animation 4 – Alternating movement

One eye moves while the other remains approximately centered. Then they switch.

Animation 5 – Random movement

The eyes move to different randomly selected positions, creating a less predictable and more natural animatronic effect.

After all five animations have finished, the sequence starts again.

Arduino IDE

The ESP32 can be programmed directly using Arduino IDE.

Install the ESP32 board support and select the appropriate ESP32-C3 board.

The code uses the modern ESP32 LEDC PWM system, so it does not require the old ledcSetup() / ledcAttachPin() functions.

Arduino Code

// ========================================== // EASY HALLOWEEN ANIMATRONIC MASK // ESP32-C3 MINI // // Left eye -> GPIO 2 // Right eye -> GPIO 3 // // 2 x 9g servo // ==========================================

#define SERVO_LEFT 2 #define SERVO_RIGHT 3

#define SERVO_FREQ 50 #define SERVO_RESOLUTION 14

// Eye positions const int CENTER = 90; const int LEFT = 55; const int RIGHT = 125;

// ========================================== // SETUP // ==========================================

void setup() {

Serial.begin(115200);

ledcAttach(SERVO_LEFT, SERVO_FREQ, SERVO_RESOLUTION); ledcAttach(SERVO_RIGHT, SERVO_FREQ, SERVO_RESOLUTION);

servoWrite(SERVO_LEFT, CENTER); servoWrite(SERVO_RIGHT, CENTER);

delay(1000); }

// ========================================== // MAIN LOOP // ==========================================

void loop() {

animation1(); animation2(); animation3(); animation4(); animation5();

delay(1000); }

// ========================================== // SERVO CONTROL // ==========================================

void servoWrite(int pin, int angle) {

angle = constrain(angle, 0, 180);

// Approximate pulse range for a 9g servo int pulse = map(angle, 0, 180, 500, 2400);

// 50 Hz = 20,000 microseconds // 14-bit resolution = 16383 uint32_t duty = ((uint32_t)pulse * 16383) / 20000;

ledcWrite(pin, duty); }

// ========================================== // ANIMATION 1 // FAST SYNCHRONIZED MOVEMENT // ==========================================

void animation1() {

Serial.println("Animation 1 - Fast");

unsigned long start = millis();

while (millis() - start < 5500) {

// Center -> Right for (int a = CENTER; a <= RIGHT; a += 2) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, a);

delay(12); }

// Right -> Left for (int a = RIGHT; a >= LEFT; a -= 2) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, a);

delay(12); }

// Left -> Center for (int a = LEFT; a <= CENTER; a += 2) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, a);

delay(12); } } }

// ========================================== // ANIMATION 2 // SLOW SYNCHRONIZED MOVEMENT // ==========================================

void animation2() {

Serial.println("Animation 2 - Slow");

unsigned long start = millis();

while (millis() - start < 5500) {

for (int a = CENTER; a <= RIGHT; a++) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, a);

delay(35); }

for (int a = RIGHT; a >= LEFT; a--) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, a);

delay(35); }

for (int a = LEFT; a <= CENTER; a++) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, a);

delay(35); } } }

// ========================================== // ANIMATION 3 // OPPOSITE MOVEMENT // ==========================================

void animation3() {

Serial.println("Animation 3 - Opposite");

unsigned long start = millis();

while (millis() - start < 5500) {

// Eyes move in opposite directions

for (int a = 0; a <= 35; a++) {

servoWrite(SERVO_LEFT, CENTER + a); servoWrite(SERVO_RIGHT, CENTER - a);

delay(25); }

for (int a = 35; a >= -35; a--) {

servoWrite(SERVO_LEFT, CENTER + a); servoWrite(SERVO_RIGHT, CENTER - a);

delay(25); }

for (int a = -35; a <= 0; a++) {

servoWrite(SERVO_LEFT, CENTER + a); servoWrite(SERVO_RIGHT, CENTER - a);

delay(25); } } }

// ========================================== // ANIMATION 4 // ALTERNATING EYES // ==========================================

void animation4() {

Serial.println("Animation 4 - Alternating");

unsigned long start = millis();

while (millis() - start < 5500) {

// Left eye moves

for (int a = CENTER; a <= RIGHT; a++) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, CENTER);

delay(20); }

for (int a = RIGHT; a >= LEFT; a--) {

servoWrite(SERVO_LEFT, a); servoWrite(SERVO_RIGHT, CENTER);

delay(20); }

// Right eye moves

for (int a = CENTER; a <= RIGHT; a++) {

servoWrite(SERVO_LEFT, CENTER); servoWrite(SERVO_RIGHT, a);

delay(20); }

for (int a = RIGHT; a >= LEFT; a--) {

servoWrite(SERVO_LEFT, CENTER); servoWrite(SERVO_RIGHT, a);

delay(20); } } }

// ========================================== // ANIMATION 5 // RANDOM / NATURAL MOVEMENT // ==========================================

void animation5() {

Serial.println("Animation 5 - Random");

unsigned long start = millis();

while (millis() - start < 5500) {

int targetLeft = random(60, 121); int targetRight = random(60, 121);

int currentLeft = CENTER; int currentRight = CENTER;

int duration = random(300, 800); int steps = 30;

for (int i = 0; i <= steps; i++) {

int leftPosition = map(i, 0, steps, currentLeft, targetLeft);

int rightPosition = map(i, 0, steps, currentRight, targetRight);

servoWrite(SERVO_LEFT, leftPosition); servoWrite(SERVO_RIGHT, rightPosition);

delay(duration / steps); } }

servoWrite(SERVO_LEFT, CENTER); servoWrite(SERVO_RIGHT, CENTER); }

Assembly

1.

Print all the mask components.

2.

Install the two 9g servos inside the head/mask structure.

3.

Connect the first servo to the mechanism controlling the left eye.

4.

Connect the second servo to the mechanism controlling the right eye.

5.

Make sure both eye mechanisms can move freely without touching the mask.

6.

Connect the servo signals:

7.

Connect both servo grounds to GND.

8.

Connect the servo power to a suitable 5V supply.

9.

Install the ESP32-C3 Mini on the expansion board to make wiring easier.

10.

Upload the Arduino program.

11.

When powered on, both eyes initially move to the center position.

12.

The five animations then run automatically in sequence.

Mechanical Setup

Before permanently fixing the servo horns, upload the program and let both servos move to 90° (center position).

Then install the servo horns so that the eyes are approximately centered.

This is important because the physical center of the servo mechanism depends on how the horn and eye mechanism are installed.

The software intentionally limits the normal movement to approximately:

55° - 125°

rather than using the full 0–180° servo range. This helps prevent the mechanism from hitting the physical limits of the mask.