KY-010 Photo Interrupter Module

From the shop's description

The KY-010 Photo Interrupter module is a switch that will trigger a signal when the light between the sensor’s gap is blocked. This module is suitable for various electronic platforms like Arduino, Raspberry Pi, ESP32, and others. Specifications: This module consists of an optical emitter/detector and 3 male header pins on the front. On the back, there are two resistors of 10kΩ and 33Ω. The sensor uses a beam of light between the emitter and detector to check if the path between both is being blocked by an opaque object. Operating Voltage 3.3V ~ 5V Board Dimensions 18.5mm x 15mm Connection Diagram Connect the power line (middle) and ground (left) to +5V and GND respectively. Connect signal (S) to pin 3 on the Arduino. KY-010 Arduino – (left) GND middle +5V S (right) Pin 3