Laser barrier gate

Why it’s here

Break the beam, observe the arm, then restore the beam.

How it works

An interrupted beam opens a striped servo barrier. A target position encoded by pulse width, rather than a continuous motor speed. This guided model targets the original ESP32 and Arduino-ESP32 3.x; radio, acoustics, loads and mechanics are simplified.

Try it

1. Open this experiment
2. Break the beam, observe the arm, then restore the beam.

Connections

• GPIO 27 — Beam receiver; LOW when lit
• GPIO 18 — Servo signal; suitable separate supply

Example sketch

#include <ESP32Servo.h>
Servo arm;
// Receiver LOW with beam present, HIGH when blocked. Verify your receiver.

void setup() {
  pinMode(27, INPUT_PULLUP);
  arm.setPeriodHertz(50); arm.attach(18, 500, 2400);
}

void loop() {
  bool blocked = digitalRead(27) == HIGH;
  arm.write(blocked ? 90 : 0);
  delay(20);
}

Check your understanding

What is the servo command?